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Greg Parent
10-16-2011, 04:34 PM
Can those in the know give me a ballpark figure to what I should expect to pay for this part;
2.125" diameter aluminum disk
0.5" thick 6061-T6 alloy
0.25" hole drilled through it in the centre
0.5" wide x 0.03125" deep slot cut across the face
six 4-40 tapped holes 60 degree apart
0.125" O-ring gland around the outside.

The O-ring gland does not need any inside radius or tapered walls.

Please excuse the rough sketch. I need two of them and don't want to waste anyones time. Thanks for any input you may have.

http://img.photobucket.com/albums/0903/MuddyTires/Anchor0001.jpg

Bill McLeod
10-16-2011, 04:40 PM
as a 1 off it will take at least 1.5 hours

macona
10-16-2011, 04:42 PM
Way more than that. 1.5 hours is conservative.

MotorradMike
10-16-2011, 04:43 PM
My guess is $150 for the two parts but what do I know.

tyrone shewlaces
10-16-2011, 05:25 PM
McMaster Carr (admittedly not the least expensive source for metal) shows a minimum length of 1 foot for a 2-1/8" rod and it is $24.62 just for the material. You do need more than the 1-1/4" just to make the lathe work simple, otherwise fixturing time will eat up the savings in a big way. I know you don't need that much, but that's probably what you'll pay unless a guy happens to have material laying around. That wouldn't be a longshot for someone to have something suitable that can be turned down or whatever, but that's the first hurdle.

I've been doing this for a while and I'd guess that it would for sure take more than an hour and possibly slightly more than two if things don't go silky. You'd have to make a mandrel to hold the pieces for drill & tap of the 6 holes unless a bolt & nut would do (not my first choice) so have to add that in.

On the rare occasion when I do a pay gig in my own shop I charge $50/hr which is probably the lowest hourly charge these days.

So looking at $125 to $175 to make two for a ballpark figure from a standard shop, IF they have the time and IF it's worth it for them to take it on in the first place. Of course 90% is setup and mandrel time so if you wanted several more then the price per part would be much less.

Your best bet is to find a hobbyist who has a mill and lathe, is skilled enough to pull it off, has the time to do it and maybe already has a chunk of material in the scrap bin to make the parts. In that case, you might get it done for $25 each, but honestly unless you're already just scraping by to make the rent and pay the bills, then it would just be polite to pay $50 each because it's going to take them at least as much time as anybody else. If you are just scraping by and don't have the expendable income, then that's understandable and you might find an empathetic soul to help you out in your area.

Anyways, my estimate would be $60 to $80 each for two pieces.
It's all eaten up in setup time.

Rosco-P
10-16-2011, 05:29 PM
$25 each? Not from my shop, I'd show you the door.

"Your best bet is to find a hobbyist who has a mill and lathe, is skilled enough to pull it off, has the time to do it and maybe already has a chunk of material in the scrap bin to make the parts.", said tyrone shewlaces.

By all means, take advantage of a hobbyist who will feel backed into a corner and compelled to deliver (at a loss) two parts for $50.

KiddZimaHater
10-16-2011, 05:49 PM
The hardest thing about making that part would be the six 4-40 tapped holes.
1/2" deep??
Is that depth necessary?
Why so deep for such a small thread?
I see several broken taps at that depth.
A 4-40 is something like .095 diameter.
Even if you double the diameter, that only gives you a needed depth of .200.
Just sayin'.....

macona
10-16-2011, 06:51 PM
One other thing, I think the dimensions are wrong for the o-ring groove. Assuming a 1/8" o-ring the depth should be shallower.

Tel
10-16-2011, 07:02 PM
Well I work pretty cheap, but you would want a hundred dollar bill in your hand to come into my shop.

tyrone shewlaces
10-16-2011, 08:42 PM
By all means, take advantage of a hobbyist who will feel backed into a corner and compelled to deliver (at a loss) two parts for $50.

Well yes and no.
That's why I qualified it by saying a) it would be good karma to pay more for the effort if the means are there and b) if the guy isn't particularly swimming in cash, then trying to get it for cheap is understandable. There have always been many people who can't just throw money at problems. If a hobbyist is willing, it's probably because it might be interesting and, dare I say it, kind of fun to make a couple parts for a "customer" and get a little practice under his belt. Most hobby work is for free, and free machining for friends and neighbors is certainly not unheard of.

Now if the guy makes 80 grand a year and takes advantage of a guy when he can honestly afford to pay fair money for the parts, then there's karma for that too :D

p.s. I agree about the 4-40 thread depth. It could be done, but why? Maybe there's a reason, but if it's just to hold a screw, then no need to design it hard to make for no good reason.
The double depth of .2" in case the OP doesn't know, is that the "rule of thumb" for depth of threads for full strength is twice the diameter of the screw. More than that (in general) doesn't gain significant strength. So for a 1/2" bolt, "full strength" would be 1" of thread and a 10-24 would only need 3/8" thread depth, etc.

Rosco-P
10-16-2011, 08:59 PM
Well yes and no.
That's why I qualified it by saying a) it would be good karma to pay more for the effort if the means are there and b) if the guy isn't particularly swimming in cash, then trying to get it for cheap is understandable. There have always been many people who can't just throw money at problems. If a hobbyist is willing, it's probably because it might be interesting and, dare I say it, kind of fun to make a couple parts for a "customer" and get a little practice under his belt. Most hobby work is for free, and free machining for friends and neighbors is certainly not unheard of.

Now if the guy makes 80 grand a year and takes advantage of a guy when he can honestly afford to pay fair money for the parts, then there's karma for that too :D

Can understand why a "senior member", unless that should read "senile member", would ask what he should pay for a basic aluminum part? Even a beginner with a chinee mill 'n lathe and 6 or 9 months shop time could turn out two good parts after some tryin. Are all of GP's machine broke?

Drilling out a broken bolt, supplying some metal from your cutoff bin, repairing a stripped thread, some quick welding, is something you do for a neighbor. Two, three hours shop time plus material is beyond doing a favor. If you're not paying shop rates, where into barter territory.


"I need two of them and don't want to waste anyones time."
Huh?

Shuswap Pat
10-16-2011, 09:04 PM
Just an asside on that 4-40 thread. If you drill it oversize, full depth, and then put a 4-4-40 helicoil in, say 1/4" long- that will give you full strength + the added depth, without the pain in the butt factor of tapping a small deep hole. And I agree - 1 1/2 hour minimum each + material - If it was easy - anyone could do it!

Patrick

beanbag
10-16-2011, 09:12 PM
1/2" thread depth isn't hard at all if you have a fast spiral tap that pulls the chips out.

I like the nut/bolt indexing idea.

I'll do both pieces for free if you buy me a Moki Seki lathe with live tooling.

tyrone shewlaces
10-16-2011, 09:17 PM
Drilling out a broken bolt, supplying some metal from your cutoff bin, repairing a stripped thread...

Uugh. I think I'd rather spin out those two parts than drill out a broken bolt. Maybe because I've done that enough to be sick of it.

Anyways, I'm probably the last guy to come to as well. I just made a drive sprocket for a neighbor's wheel loader a few days ago (hub, shrink & weld) and it cost him a couple hundred for a couple hours' or so work. I have neither time nor money, but less of the time these days so I try to avoid taking on any side jobs, thus the decent price tag. But it was still half the price of the part from Case.

Funny when I was younger I had extra time to take on all sorts of hobbies and group activities and such, and now I don't have any free time even though it's just down to "job and family". Oh well. Maybe I'm just better at taking care of the necessities than I used to be and it just takes longer to do it right.


I'll do both pieces for free if you buy me a Moki Seki lathe with live tooling.
Yea, that's the ticket. One op and it's done. Still take 1-1/2 hours or so to set up and program though. It's worth it for the machine I guess.

Rosco-P
10-16-2011, 09:25 PM
Uugh. I think I'd rather spin out those two parts than drill out a broken bolt. Maybe because I've done that enough to be sick of it.


Some jobs you just get better at by sheer repitition. Ignoring the "free" advice sometime given by the part owner speeds up the task as well.

If a friend ever finishes his spark, tap/bolt eroder, I might just copy his design.

tmc_31
10-16-2011, 09:44 PM
Wow, Iv'e been following this thread from it's beginning and completely missed where Greg said anything about broken screws.

Just looking at what Greg is showing, I'm thinking it might take me 3-4 hours to make two of these parts in my manual only hobby machine shop (and I could be way off). I am interested in hearing how long it should take in a for profit job shop by a competent machinist.

Tim

macona
10-16-2011, 10:06 PM
Depends on what the job shop has in the way of machines. If they have a CNC lathe with live tooling and a Y axis, well, assuming it can all be done in conversational he could probably program the part in a half hour, set up tooling and cut two in another hour. Figure $125 an hour.

About the same here at home on my equipment. Slice off a piece in the lathe, face, turn the groove, drill the hole, part, flip and face. Make a fixture to hold the part in the mill for the face groove. Set up the indexer with the external jaws for the six holes. 1-1/2 to 2 hrs. And I charge $75 an hour.

Tait
10-16-2011, 11:41 PM
I'm curious (if it's not a secret): What are the parts for?

J Tiers
10-17-2011, 12:05 AM
MAKING them takes not *too* much time....... but SETTING UP will be more than $25.

2 mill setups (slot and DH for drilling), two lathe setups, assuming cutoff and subsequent face to length, since cutoff is not (for me) accurate and clean at 2"+ diameter.

If you have the "daylight" the slot might be a "tip-up" of the DH. (I don't)

You can get these for a low cost each if you want a few thousand of them.......... One-off from a general purpose shop, not so cheap

danlb
10-17-2011, 12:22 AM
I'd be disqualified at the following part of the spec:

0.5" wide x 0.03125" deep slot cut across the face

The tolerances are not specified, but I can't get close to 5 decimals of precision.

Dan

Duffy
10-17-2011, 01:09 AM
I think that Greg is dreamin in technicolor! Shop time in just about ANY shop in the Ottawa area is $85.00/hr or more. It looks like everyone agrees on "about" 1.5-2 hours. The material has to cost something. I would expect that the SALES TAX will be close to $25.00, and it cannot be avoided at a commercial shop.

Eagle_view
10-17-2011, 02:40 AM
I would bet the Greg already had quotes and was not prepared for the reality of the cost. I would say that $75.00- $95.00 each would be fair if it was not a rush job.
Lowell

DR
10-17-2011, 07:33 AM
The first cost in this job would be to sit down for at least 1/2 hour and go over the dimensions. It seems obvious the 4 decimal place accuracy is probably not needed when combined with the single digit dimensions in places. That'll cost you 50 bucks or so. Included would be reworking drawing so a machinist could understand it whiteout further explanation.

Reduce all dimensions to 3 three places with the .005+/- tolerance and I'd guess about 3 to 4 hours minimum at least.

One of the major issues with this part is how to hold it. Like, how do you hold it to do the tapped radial holes? A step collet is the way I see. How many shops have a shallow grip 2-1/8" collet on the shelf? You'd be 1/2 hour or so to bore out a relatively expensive emergency collet blank (the collet itself is close to a hundred bucks, it will have other uses, it's not totally wasted on this job).

Given the poor quality of the drawing, in all likely hood I'd send the customer down the road. These type parts are always a waste of your time to get involved in since the customer really has no idea how complicated and expensive they are to setup.

J Tiers
10-17-2011, 09:40 AM
WHY is everyone obsessing about tolerances?

The man STATES ON THE DRAWING that tolerance is 0.005" +- It is right up at the top in BIG letters......

0.03125 is just 1/32" given to a decimal that doesn't accord with the tolerance. I know it is 1/32".....+- 0.005"......... there is no "except as noted" on the drawing, so EVERYTHING is 5 thou, no exceptions

vpt
10-17-2011, 10:10 AM
You guys must be slow workers. I bet I could whip those things out in 45 minutes each and have less then half the tools some of you have.

Rustybolt
10-17-2011, 10:19 AM
You guys must be slow workers. I bet I could whip those things out in 45 minutes each and have less then half the tools some of you have.


45 X 2 = 1.5 hrs. about right.

vpt
10-17-2011, 10:23 AM
45 X 2 = 1.5 hrs. about right.


With half the tools. ;)

JCHannum
10-17-2011, 11:22 AM
With half the tools. ;)

The only problematic part of the job is the radial 4-40 D&T holes. A dividing head would probably be the simplest solution for that, otherwise the job is a simple lathe & milling machine project.

While actual machine time could quite possibly be something under an hour each, setup, teardown, cleanup, material ordering and design discussion and clarification with the purchaser all add to billable shop time.

If a HSM is content with occasionally pocketing $50.00 for fiddling around in his shop for an evening, that is one thing. But if a for profit shop is involved, the reality is that bills must be paid, and a couple of hours will be involved at the going shop rate.

DR
10-17-2011, 01:03 PM
WHY is everyone obsessing about tolerances?

The man STATES ON THE DRAWING that tolerance is 0.005" +- It is right up at the top in BIG letters......

0.03125 is just 1/32" given to a decimal that doesn't accord with the tolerance. I know it is 1/32".....+- 0.005"......... there is no "except as noted" on the drawing, so EVERYTHING is 5 thou, no exceptions


The drawing as supplied differs in so many respects from accepted standards of drawing and dimensioning you would have to sit down for the 1/2 hour or so and determine exactly what he wanted. Yes, he did spec the +/-.005 tolerance, but I wouldn't trust it based on his non-standard style.

Greg Parent
10-17-2011, 01:06 PM
Let`s see if I can provide a little background info and answer some questions…

The local professional shops are not interested in small jobs like this. I have tried multiple times in the past and if I get a response from my queries they end up quoting prices that would kill the project. I know all the reasons why they do it and I respect them, I just cannot go that route in the prototyping phase of the projects I have shown them. This is the reason why I posted this on a Home Shop Machinist Forum. I have in the past had great success with hobby machinists making parts in their spare time and both of us walking away from the deals happy. The idea a hobbyist will feel backed into a corner and compelled to deliver (at a loss) is absurd. This is not communism and no one has a gun pointed at their heads. If you are not interested in the job don’t offer to make the parts...pretty simple.

That being said lets move on to what can be done.

Drawing: I don’t know how to draw using CAD or whatever software is used to make official “hobby” machinist drawings so what you see is what you get. I am sure a little communication can sort out any sketchy details on the drawing to the satisfaction of who ever took on the job. Again, I am not a machinist nor have I played one on TV.

Material: I was thinking that the starting material could be a scrap of 0.5” thick plate. The idea of starting with 2.125”round stock is a good one. How to hold the plate or round stock may have more options that what the original drawing shows as some comments got me to thinking about changing the design. I could get rid of the ½” wide x 1/32” deep slot and just drill two ¼” holes 1.5” apart instead. This would be a detail worked out with the interested party.

Tolerance for all values is +/- 0.005” Any values with more than three decimal places are because I was reading a chart I have that converts fractions to decimals. I just copied what I saw.

The issue with the 0.5” deep tapped 4-40 holes is something as a non-machinist I was unaware of. I learnt something new reading this point. The 0.5” deep tapped hole was only because I have 0.5” screws already. Not being a machinist I had no idea about the "rule of thumb" for depth of threads for full strength is twice the diameter of the screw.
Thanks for that info and again it was nice to learn something. The specs for the tapped holes can be changed to the accepted standard of twice the diameter. I will trim the screws I have to fit.

The O-ring gland is another learning experience. I took a look on a few websites that show O-ring and gland dimensions and drew what I understood. It appears I made a mistake. Good thing I posted this on a forum with knowledgeable people.

Why am I not doing this work myself? I lost my home workshop and almost all my tools to a major downsizing. Let’s just say women can change your life in ways best left unsaid on public forums. All I have left is a plastic toolbox, a hammer, a multi-bit screw driver a piece of sandpaper and a roll of tape.

As for the price per part question stated in the subject line of the original post, its intention was that of a question to get the ball rolling in the free exchange of ideas. I had no previous professional quotes or even a reasonable idea of the difficulties making the part with the “issues” that were pointed out. With all deals I have no problem negotiating with someone who is willing to take on the project.

If anyone is still interested please let me know and we can take the discussion to the private message side of the website.

Thanks again for all the input.

Greg Parent

Stepside
10-17-2011, 02:53 PM
This has been a good thread for several reasons. 1) the discussion of what shop time is worth. 2) Why it takes almost as much time to make 2 as it does to make a dozen. 3) The concept of how deep to tap a threaded hole. 4) why a drawing has "standards". 5) read the whole OP's description as well as his questions.

Most importantly is what is happening in education/training today. Many engineers, architects and designers are graduating without any hands on training. There seems to be a belief that if you can draw or 3D model it, then it is easy to build it. Most times the tooling/fixturing takes as long or longer to build than the part does. For instance if this part had a through hole or a deeper bore, it would be easy to do most of the work on an arbor or expanding collet. With only the shallow bore the workholding/fixturing is far more complicated.
Not included in any of the estimates is the charge for shipping the part as well as any mention of when it would ship. If it is a ship when handy, machine when you have spare time, the price could be lower than "I need it now".

Rosco-P
10-17-2011, 03:10 PM
The local professional shops are not interested in small jobs like this.

The idea a hobbyist will feel backed into a corner and compelled to deliver (at a loss) is absurd. This is not communism and no one has a gun pointed at their heads.

Material: I was thinking that the starting material could be a scrap of 0.5” thick plate. The idea of starting with 2.125”round stock is a good one.
Greg Parent

They probably would be happy to make two of the parts, at standard shop rates. Not for the ridiculous $25 a pop.

If a person accepts a a job, knowing from the outset what the details are, an honorable person would feel compelled to deliver.

Utilize a "scrap" of ......plate or round bar? Where did the scrap come from? Heaven?

Post an RFQ for your part on classified section of Practical Machinist. I think the replies will be very entertaining for all of us here.

DR
10-17-2011, 03:22 PM
.................................................. ...............................................


Most importantly is what is happening in education/training today. Many engineers, architects and designers are graduating without any hands on training.

.................................................. ...............................................


.


I think that may be changing.

When I was in engineering school (ME & CS) for our required shop classes we had old WWII machines and assigned projects that were the same as had been done since 1950. Boring.

Flash forward about 30 years when I went to the engineering open house. All newish manual and CNC machines. Students choose their own projects, with instructor approving if they give a somewhat broad exposure to manufacturing.

I currently work with a non-profit that employs young interns who are recent engineering graduates. These "kids" are sharp. They have a much more in depth understanding of manufacturing than the typical grad in my day. They constantly surprise me talking about their wire EDM and rapid prototyping projects and other slightly exotic manufacturing experiences in school.

lynnl
10-17-2011, 03:42 PM
For instance if this part had a through hole or a deeper bore, it would be easy to do most of the work on an arbor or expanding collet. With only the shallow bore the workholding/fixturing is far more complicated.


Though the "side view detail" doesn't show it, I'm guessing that 1/4" hole in the center is a through hole. ...the side view also doesn't show it as a stopped hole either. It appears to have just been inadvertently omitted.

Maybe I missed something.

Oh yeah, on his 4th line he states: "0.25" hole drilled through it in the centre"

Ries
10-17-2011, 05:46 PM
I think the time and price estimates are close- but I would do this a whole different way.

First, cut to very slightly overlength on the cold saw- about 1 minute.
Then, slap the part in the 4 jaw chuck I have mounted on my rotary table.
Face with an end mill, flip, face again for part length.
Mill slot while part is still sitting in the rotab.
Drill center hole and 6 radial holes- again, same setup, easy to get 60 degree spacing by just cranking the rotab.

Then, flip up rotab to vertical position, without removing part, and mill o ring slot with ball end mill.

last, hand tap holes.

No lathe needed.

ckelloug
10-17-2011, 06:43 PM
Ries,

Why the ball end mill for the o-ring groove? All of the o-ring design manuals I've seen use square bottom grooves in the gland to give the o-ring a place to deform to when squeezed.

--Cameron

RussZHC
10-17-2011, 07:02 PM
I for one, who has never had to use proper drawings (did do some drafting way back in high school, so get the concept) even in a HSM am beginning to understand the points being made about time spent on clarification.

Not slagging the OP but as an example, IF changing the slot to 1/4" holes 1 1/2" apart, that puts the edge of the hole at an 1/8" from the edge of the part (assuming "apart" is center to center) and if using some sort of cap screw, nut or hollow hex head, will that not put the edge of the fastener right at or over the edge of the part?
This may or may not be important but as few have pointed out, for a professional this needs discussion and that is time.
[of course, I could have the math wrong :o ]

lynnl
10-17-2011, 07:22 PM
I
Drill center hole and 6 radial holes- again, same setup, easy to get 60 degree spacing by just cranking the rotab.

Then, flip up rotab to vertical position, without removing part, and mill o ring slot with ball end mill.

last, hand tap holes.



The six radial holes are ...well, radial. So you'd need to flip to vertical for those.

Ries
10-17-2011, 07:38 PM
Both corrections are right- not reading the drawing very carefully- but my basic premise still works- this is a quick job with a rotary table, with a 3 or 4 jaw chuck on it. I have both chucks for my rotab, mounted on backing plates that bolt down to the t slots. Just dial em in when you mount the chucks.

macona
10-17-2011, 08:02 PM
I think the time and price estimates are close- but I would do this a whole different way.

First, cut to very slightly overlength on the cold saw- about 1 minute.
Then, slap the part in the 4 jaw chuck I have mounted on my rotary table.
Face with an end mill, flip, face again for part length.
Mill slot while part is still sitting in the rotab.
Drill center hole and 6 radial holes- again, same setup, easy to get 60 degree spacing by just cranking the rotab.

Then, flip up rotab to vertical position, without removing part, and mill o ring slot with ball end mill.

last, hand tap holes.

No lathe needed.

Typical spec for o-rings grooves is they must be turned. Milling leaves grooves perpendicular to the groove which can allow leaking where turning leaves grooves parallel to the groove and the o-ring can seal.

mochinist
10-17-2011, 10:05 PM
Lay out and cut 2 1/4" square of 1/2 plate on bandsaw plus light deburr x 2
=10 min

Take over to bridgeport and toe clamp the part to the table, center the center of the block over a t slot so I can drill and ream the 1/4 thru hole through the center of the block without drilling into my table. Ill also add in the .031x.5 slot at this time . x 2
=20 min maybe 25 if I have to go take a piss or fill up my coffee.

Grab a piece of 2" dia stock out of my stock bin and chuck it up in the lathe, face it, drill and tap a 1/4 hole and then use a 1/4 bolt and a washer and mount it to the piece I drilled in the step before this, torque it down tight.. Turn the lathe up and turn the sawed out square stock to the 2.125"dia dimension, also add in the o-ring groove(to the correct depth ) x2
=45min

Take the parts back to the bridgeport, I dont feel like getting out the dividing head, so I will just cheat and use another 1/4 bolt locked on with a nut and can set the edge of the bolt head on a parrallel in the kurt vice. I'll set up an edge stop, so I only have to pickup the center once. I dont see any callout for the 4-40 holes being clocked to any feature on the part? If there is, no biggie, just adds a few more minutes to get the bolthead clocked to a feature.
x2
=45min

http://www.cdxetextbook.com/images/fourbolts.jpg

Do a quick QC, clean the parts, clean up the machines used and put tools away
=15 to 20 min

so about 2 to 2.5 hours at 65 an hour for a job shop price. I could probably do the job a bit quicker if certain moons and stars were aligned for the day and the cnc mill and some other tooling were ideally setup to do it another way I see in my head.


Seems to me most of the guys that have home shops and compete with me, have shop rates closer to the 30 to 40 dollar an hour range. Depending on their skill level, they could do the same job faster, as fast or maybe an hour longer for the least skilled that can get away with charging.

Dragons_fire
10-17-2011, 10:36 PM
I am just a hobby machinist, and have never built anything where tolerances were much of an issue, however i have a different idea on how to make these parts.

I would start with a 2" long piece of 2.25" round that would cost $17CAD from my expensive supplier. I would mount it in the lathe, turn it down to the required diameter, drill the center hole and add the o-ring grooves. Then i would take it to the rotary table in the mill and drill all 12 radial holes.

Then take it back to the lathe, part off the 2 seperate parts, and face to the required thickness. Then back to the mill one last time to cut the grooves along the face.

I think it would only take me about 2 hours to whip off both parts, and if it was local i would probably do it for a case of beer. :)

morehelium
10-17-2011, 11:22 PM
Greg,

Go here:

http://www.parker.com/literature/ORD%205700%20Parker_O-Ring_Handbook.pdf

(warning - large pdf file)

Its the Parker O-ring handbook. Probably the best reference there is on the subject.

A 1/8" o-ring is actually 0.139 dia. For a static seal your groove should be 0.111 to 0.113 deep and 0.187 to 0.195 wide.
The o-ring should always be loose in the groove on the sides. A dynamic seal will have a little less squeeze.

Lots of info on how o-rings work, materials, fluid compatability etc. in the Parker book.

Chris

lbhsbz
10-18-2011, 12:30 AM
I'll do 'em both for $100....only because I've still got the rotary table standIng up on the mill...and that sucker is heavy...I'd like to make a littlemore money at it before lifting the damn thing off of the mill.

I've got a chunk of 2.5" round, throw it in the lathe, take
It down to diameter, drill the center hole, in the rotab for the radial holes, back in the lathe to part, then in the vise to slot. Done

J Tiers
10-18-2011, 12:47 AM
The drawing as supplied differs in so many respects from accepted standards of drawing and dimensioning you would have to sit down for the 1/2 hour or so and determine exactly what he wanted. Yes, he did spec the +/-.005 tolerance, but I wouldn't trust it based on his non-standard style.

The man done wrote it on the drawing....... you HAVE to believe it, or you are adding your own info to the drawing.

I've been drawing, reviewing, approving, and occasionally working to drawings for 30+ years, and I had the part figured out in under 5 min from that drawing. it isn't standard, but it's all there. In fact there is "too much" there..... ;)

beanbag
10-18-2011, 02:04 AM
No, pick me! I'll do it for $99!

DATo
10-18-2011, 04:45 AM
I took a lot of heat from the forum once for lowballing on a project such as this by another member but if I were retired I'd do this job for about $50 (material and any unusual tooling provided by customer). I get up very early in the morning and I'd do this project while having my morning coffee, have it done before the sun was up and have the rest of the day for myself. I have no overhead. When I turn the light switch off in my shop I turn my overhead off. In fact this is precisely the kind of project, income and circumstance I'd be shooting for when I retire.

If working cheap could get me an average of $50 / day ($250 - $300 a week) I could pay most if not all of my home utility bills for the year and maybe even some of the taxes and insurance, and that would be my goal. I would take into consideration the "Pain In The Ass" factor when quoting though. Simple work like this is a breeze but work requiring a lot of R&D or running around town for materials and tooling would up the quote considerably, and if they don't like it they can walk, after all I'd be retired and I didn't retire to confront a pain in the ass retirement.

In short, I'd prefer a steady stream of work to being idle and if lowballing will guarantee me customers on a steady basis I'd prefer that to idleness and zero income. First priority - bring in the customer. Sooner or later the occasional "windfall" projects will arrive and those will be the bonuses. More satisfied customers = greater probability of occasional gravy which would be welcomed but not necessary for nice, supplemental retirement income.

RussZHC
10-18-2011, 08:18 AM
Not aimed at DATo or anyone else, but how far do you go to "support the cause"?

I.e. the OP situation states no professional shop will touch such a project, so at what point does "lowballing" by the HSM intercept that line of taking monies away from those doing this for a living?
I know it depends on the HSM not being professional (in the sense of overhead, level of income from machining, NOT in terms of doing things in a professional manner)...
Or, perhaps more importantly, in this example, not "lowballing" oneself into the poor house? I mean if you think about the other side, the OP is in the position where, if the work is to be done, the HSM is in the drivers seat.


Extend question to supporting the home economy in general, home being municipality, provincial/state, federal since I feel the mindset is similar? Do you pay more for products from local sources, as opposed to off shore, in your efforts?

P.S. I happen to agree w DATo esp the statement re: work flow

Rosco-P
10-18-2011, 10:00 AM
In fact this is precisely the kind of project, income and circumstance I'd be shooting for when I retire.

If working cheap could get me an average of $50 / day ($250 - $300 a week) I could pay most if not all of my home utility bills for the year and maybe even some of the taxes and insurance, and that would be my goal.

If that's you goal, $7+ an hour, work for Wallmart, Sears, Home Dee, Lowes, etc. Less stress, no kooks to deal with who think you should take their simple machining jobs for peanuts.

lwalker
10-18-2011, 01:06 PM
I'm decades from retirement (and that's assuming I can even ever afford to!), but I get what DATo is saying. What he's after is life on his own terms, doing stuff he likes and making enough to get by.

That's a lot different than taking a job you hate just so you can pay the bills. I'd find Wal-Mart, etc. much more stressful than what he describes.



If that's you goal, $7+ an hour, work for Wallmart, Sears,
Home Dee, Lowes, etc. Less stress, no kooks to deal with who think you should take their simple machining jobs for peanuts.

Peter.
10-18-2011, 01:25 PM
If that's you goal, $7+ an hour, work for Wallmart, Sears, Home Dee, Lowes, etc. Less stress, no kooks to deal with who think you should take their simple machining jobs for peanuts.

No thinking, no enthusiasm, no satisfaction either.

I've made loads of parts for bikes for people and usually I charge nothing at all. Mostly I get paid in beer if anything. I don't rely on the work for money, already got a very busy full-time job, and I don't even drink much beer so I end up bartering that off when the stack gets too high.

For some people, doing stuff is not always about getting paid.

mochinist
10-18-2011, 01:34 PM
That's a lot different than taking a job you hate just so you can pay the bills. I'd find Wal-Mart, etc. much more stressful than what he describes.is it the outfit that would stress you out?
:p
http://blogtown.portlandmercury.com/images/blogimages/2009/05/08/1241805647-wm.jpg

mochinist
10-18-2011, 01:38 PM
The man done wrote it on the drawing....... you HAVE to believe it, or you are adding your own info to the drawing.

I've been drawing, reviewing, approving, and occasionally working to drawings for 30+ years, and I had the part figured out in under 5 min from that drawing. it isn't standard, but it's all there. In fact there is "too much" there..... ;)DR probably works at a shop where they never see anything but fully detailed drawings done up by engineers, nothing wrong with that... I agree that there is plenty of info on that drawing and any info not there could be found out with a pretty quick conversation. I work from hand drawings like this all the time with different customers and frankly this one is one of the better ones I see as far as details go.

Boostinjdm
10-18-2011, 04:37 PM
Don't complain about drawings too much. Next time you have a gripe, consider that some people don't get drawings at all. I tend to get very vague verbal descriptions using all the wrong terms from farmers. It usually ends with me getting in my truck and going to make my own measurements/drawings. Then I have to hope I made what they envisioned.

lakeside53
10-18-2011, 11:21 PM
No thinking, no enthusiasm, no satisfaction either.

I've made loads of parts for bikes for people and usually I charge nothing at all. Mostly I get paid in beer if anything. I don't rely on the work for money, already got a very busy full-time job, and I don't even drink much beer so I end up bartering that off when the stack gets too high.

For some people, doing stuff is not always about getting paid.


+1... I fix damn near everything in the neighborhood. I recently spent 3 days working on a friend's stuff. I'm sure he thought it would take a few hours, but... that's what friends do..

But I drink beer so the stack eventually goes way :D

Cheeseking
10-18-2011, 11:44 PM
I made a small part for OP few years ago as a favor. Took me a few hrs time. I didn't charge anything but he did send a small cash token as a thank you. Covered my shipping and bought me a case of beer. Some sort of rocket part IIR

DATo
10-19-2011, 06:28 AM
If that's you goal, $7+ an hour, work for Wallmart, Sears, Home Dee, Lowes, etc. Less stress, no kooks to deal with who think you should take their simple machining jobs for peanuts.

Well ..... because I'd rather walk through the door of my house directly into my heated / air conditioned shop and work on my machine tools when I feel like it rather than drive through the snow to Wal-Mart to stack shelves when they say I have to be there. Both jobs pay $7 ... which would you choose ?

A.K. Boomer
10-19-2011, 10:01 AM
Good point there Dato - damn good point...

Greg Parent
10-19-2011, 10:03 PM
I got out my big bucket of correction fluid and came up with this modified diagram. Groove replaced by two 0.125" holes, 4-40 tapped holes closer to standards, o-ring gland details other than centreline left up to part maker(based on using a 0.125" thick o-ring), etc.
Thanks for all the constructive criticism given on version 1 and please keep it up for version 2. You live, you learn.
Greg
ps. No Wal-Mart stock persons were injured in the drawing of this part.

http://img.photobucket.com/albums/0903/MuddyTires/bulkplate20001.jpg

jkilroy
10-19-2011, 11:28 PM
"Why am I not doing this work myself? I lost my home workshop and almost all my tools to a major downsizing. Let’s just say women can change your life in ways best left unsaid on public forums. All I have left is a plastic toolbox, a hammer, a multi-bit screw driver a piece of sandpaper and a roll of tape."

Greg,

All I have to say about that is, THAT SUCKS! I really feel for you man, been there, done that myself. I'd rather give up my left nut than my shop.

On edit, I'd add a very slight, tiny even, relief groove centered over the 4-40 holes. Because of the o-ring I am guessing this thing goes up inside something else? If thats the case, tapping the 4x40 will raise a burr on the OD that will have to be removed if this is to have any kind of close sliding fit. If you cut a very slight groove and drill and tap the holes inside this groove you will not have to worry about the burr.

ahidley
10-20-2011, 12:22 AM
Now I'm confussed, The o-ring groove is not dimensioned. You said "o-ring land for a .125 o-ring" Isnt that like an engineer saying "cut deep enough so it wont leak". Then when it leaks its the machinests fault. Please specify with dims for o-ring groove.

In the top view you show six 4-40 holes and in the view under that you show three holes horizontally located but you dont say if any of them are related to the 4-40 holes.

The side view detail should be rotated 90 degres so it is folded off the front view correctly. i.e. top, front , right side view. What you have would work but if any of the three holes were not thru then you may end up with a back wards part because the views are not folded correctly.

You have PM

Greg Parent
10-20-2011, 12:15 PM
...I lost my home workshop...All I have to say about that is, THAT SUCKS! I really feel for you man, been there, done that myself. I'd rather give up my left nut than my shop.
On edit, I'd add a very slight, tiny even, relief groove centered over the 4-40 holes. Because of the o-ring I am guessing this thing goes up inside something else? If thats the case, tapping the 4x40 will raise a burr on the OD that will have to be removed if this is to have any kind of close sliding fit. If you cut a very slight groove and drill and tap the holes inside this groove you will not have to worry about the burr.

Hello jkilroy,
Thanks. It does suck. The relief groove around the threaded holes is a very clever idea. I will incorparate it in future designs. For these two parts I will have to go with the current diagram as I want to reduce the number of steps for the person who takes on the job.

Hello ahidley,
I took out the o-ring dimensions other than its location thinking that the person who took on the job would know how to make it. I am currently reading the excellent resource I was told about on o-ring design by HSM member morehelium (Thanks for the link).
Stay tuned, I will post the dimensions as soon as I can figure them out.

I could not figure out how to draw all the info on one image in the diagram so I put the radial position of the 4-40 holes on one image (middle), the location of the 4-40 holes in relation to the o-ring gland on another image (top) and the three horizontally aligned holes on another image (bottom top view and side view).

The three holes on the top of the part are all drilled through.

Thanks again for the comments here and the quote in your PM.

Greg

MotorradMike
10-20-2011, 01:34 PM
I don't understand why you guys are being so picky about:
1/ The drawing
2/ The fact that he wants the parts cheap
3/ The fact that he doesn't know what size groove the O-ring needs

1/
If you can't work from a sketch, that speaks more to your own ability than that of the sketcher. I've built good parts from "drawings" on 1-1/2" x 2" sticky notes accompanied by lots of hand waving.
A sketch like this invites questions if unclear.

2/
Most of us know $25 is too low. Say so once and move on.

3/
So what? Look it up and suggest dimensions. I'm sure he'd update the sketch and send it back so you don't get sued.

Quite frankly, I'd rather deal with a backyard inventor than an ISO 9000 shop that wants something built to MIL-TFD-41.
Not this time, but sometimes, the backyard inventors have money.

Thruthefence
10-20-2011, 04:05 PM
I wonder what the "sketch" looked like for this thing?

http://tinyurl.com/3rplncw

vpt
10-20-2011, 04:55 PM
I don't understand why you guys are being so picky about:
1/ The drawing
2/ The fact that he wants the parts cheap
3/ The fact that he doesn't know what size groove the O-ring needs

1/
If you can't work from a sketch, that speaks more to your own ability than that of the sketcher. I've built good parts from "drawings" on 1-1/2" x 2" sticky notes accompanied by lots of hand waving.
A sketch like this invites questions if unclear.

2/
Most of us know $25 is too low. Say so once and move on.

3/
So what? Look it up and suggest dimensions. I'm sure he'd update the sketch and send it back so you don't get sued.

Quite frankly, I'd rather deal with a backyard inventor than an ISO 9000 shop that wants something built to MIL-TFD-41.
Not this time, but sometimes, the backyard inventors have money.



I as well have had to build stuff from sketchy instructions. The worst probably was when someone held up their fingers and said "about this wide, this tall, and this long, with a hole on each end."

Black Forest
10-20-2011, 05:33 PM
I as well have had to build stuff from sketchy instructions. The worst probably was when someone held up their fingers and said "about this wide, this tall, and this long, with a hole on each end."


I went to my hydraulic guy to get a hose. He asked how long. I held up my hands and said, "about this long" He shakes his head and pulls out his tape and measures between my hands. Then he makes a comment about how he can't believe you Americans put a man on the moon!

vpt
10-20-2011, 07:21 PM
I went to my hydraulic guy to get a hose. He asked how long. I held up my hands and said, "about this long" He shakes his head and pulls out his tape and measures between my hands. Then he makes a comment about how he can't believe you Americans put a man on the moon!


Tolerances are over rated in space. The vacuum holds everything together.

DR
10-20-2011, 07:44 PM
I don't understand why you guys are being so picky about:
1/ The drawing
2/ The fact that he wants the parts cheap
3/ The fact that he doesn't know what size groove the O-ring needs

1/
If you can't work from a sketch, that speaks more to your own ability than that of the sketcher. I've built good parts from "drawings" on 1-1/2" x 2" sticky notes accompanied by lots of hand waving.
A sketch like this invites questions if unclear.

2/
Most of us know $25 is too low. Say so once and move on.

3/
So what? Look it up and suggest dimensions. I'm sure he'd update the sketch and send it back so you don't get sued.

Quite frankly, I'd rather deal with a backyard inventor than an ISO 9000 shop that wants something built to MIL-TFD-41.
Not this time, but sometimes, the backyard inventors have money.



One word why I'm picky about all three items you mention, the word is EXPERIENCE.

What I mean by that is after 30 or so years having a commercial shop I KNOW this type of job is going to be trouble. There are too many questions about the drawing so it can't be given directly to your machinist to make the parts.

The OP stated "professional" (commercial) shops are not interested in this type part. I can't speak for those shops, but I know we did this kind of work all the time ad other shops in my area also do them.

One good piece of advice I got early on, if someone comes into the shop and says they're an inventor show them the door. I may have been a slow learner, it took me a couple years to realize how good that advice was. Most of my work was in product development, which you might say was working with inventors, but in all the years I don't recall any of my good customers describing themselves as inventors. Those who claimed to be inventors were all problems (you'd be surprised how many offered me part interest in their wacko inventions when it came time to pay their bills).

DR
10-20-2011, 07:58 PM
I think the time and price estimates are close- but I would do this a whole different way.

First, cut to very slightly overlength on the cold saw- about 1 minute.
Then, slap the part in the 4 jaw chuck I have mounted on my rotary table.
Face with an end mill, flip, face again for part length.
Mill slot while part is still sitting in the rotab.
Drill center hole and 6 radial holes- again, same setup, easy to get 60 degree spacing by just cranking the rotab.

Then, flip up rotab to vertical position, without removing part, and mill o ring slot with ball end mill.

last, hand tap holes.

No lathe needed.


Minor point, you will need a lathe because the tolerance on cold finished 2-1/8" bar is wide enough that you can't be guaranteed the bar will be 2.125 +/-.005". You need to start with 2-1/4" bar and turn to size before sawing off.

sansbury
10-22-2011, 01:42 PM
+1 to Motorrad Mike's comment #63.

The way I deal with tolerances from backyard inventor types is to ask about the purpose of the part. Nine out of ten times, the explanation makes abundantly clear that I could measure it by eyeball and cut it with a hacksaw and it'd work fine. Usually I'll make it my way and tell them if it doesn't work because the dimensions are off, I'll make it again at my expense. I'm sure I'll get bit one of these days but haven't yet.

Rosco-P
10-22-2011, 02:10 PM
One good piece of advice I got early on, if someone comes into the shop and says they're an inventor show them the door.


Is GP playing the role of backyard inventor here? He states he no longer has a shop. Is he just being a middleman trying to get the part made for said inventor on the cheap, because he low-balled his quote? Either way, despite the endless debate, it doesn't look like anyone has stepped up to the plate and committed to take on this money loser of a job.

Lets move on.

snowman
10-22-2011, 05:28 PM
If you can't work from a sketch, that speaks more to your own ability than that of the sketcher. I've built good parts from "drawings" on 1-1/2" x 2" sticky notes accompanied by lots of hand waving.
A sketch like this invites questions if unclear.

Quite frankly, I'd rather deal with a backyard inventor than an ISO 9000 shop that wants something built to MIL-TFD-41.
Not this time, but sometimes, the backyard inventors have money.

The thing is, a sketch like this invites a good machinist to make bad parts.

I used to job out some work to a guy who worked out of his garage. If my drawing wasn't to industry specs, he'd throw it back in my face. At the same time, if I took him a gear and said, "make me another"....I'd have it back in no time with no questions. He worked largely for local farmers and they'd bring him stuff and say, "make it work".

When you work from a napkin sketch, you have to have a good idea what you are doing and understand the work....when you work from a drawing, you have to have the rules specified.

So here are some suggestions....

In the case of fractional conversions, just write the fraction then put the tolerance down, if you put 5 decimal places, it invites confusion.

I wouldn't consider this part confusing enough to use cross sections...or, if you feel you need a cross section, you need a conventional three view drawing with hidden lines and appropriate leaders in the most descriptive view, as well as your cross section appropriately called out and put of to the side.

For example, your 4-40 through. You have six occurances. You label the circle ONCE on the side view, where you can see the circle. You say, "Drill & Tap for 4-40, 1/2" thread depth, (typ)".

For your 1/4" through hole, you just label, "1/4" Diameter".

Dimension diameters with leaders, not drop down lines.

I'd suggest getting a high school drafting book and looking through it. You can make an easy part look much more difficult without appropriate dimensioning/drafting technique.

As for the cost, I'd be happy to do them for $25 each with a couple week timeframe, the tapping sounds like a challenge....but any job shop will be charging you probably $300 for two of them.

snowman
10-22-2011, 05:33 PM
Is GP playing the role of backyard inventor here? He states he no longer has a shop. Is he just being a middleman trying to get the part made for said inventor on the cheap, because he low-balled his quote? Either way, despite the endless debate, it doesn't look like anyone has stepped up to the plate and committed to take on this money loser of a job.

Lets move on.

When my uncle was in boot camp, he was offered one of the initial investment opportunities for a company that was going to do nothing but sell premade coffee.

His opinion...why would someone want to go to a restraunt that sells only coffee.

He missed out on basement level investing in Starbucks.

Everybody has a reason for what they do. In my case, I offered to make this job because I've never tapped 4-40, let alone at that depth. It's a learning opportunity with boundries...and I've got time on my hands.

Mcostello
10-22-2011, 10:50 PM
Just wondering , how many taps can you get for $25 if there is trouble?

Tony Ennis
10-22-2011, 11:01 PM
The tolerances are not specified, but I can't get close to 5 decimals of precision.

Heh, I can get close to 5 digits of precision... :D

J Tiers
10-22-2011, 11:45 PM
I do ALL my machining to 6 digits precision. What's wrong with you folks?

Boostinjdm
10-23-2011, 01:55 AM
I do ALL my machining to 6 digits precision.

I do too, but the last three are usually zeros.:D

vpt
10-23-2011, 08:54 AM
I do too, but the last three are usually zeros.:D


And to the left of the '.' :D

Duffy
10-23-2011, 10:51 AM
Jerry, are those "six digits of percision" the thumb and four fingers of your left hand and the thumb of your right hand?:D

Tony Ennis
10-23-2011, 11:17 AM
I do ALL my machining to 6 digits precision.



I do too, but the last three are usually zeros.

I don't know what the last 5 are, but I'm sure they are something!

RKW
10-23-2011, 11:24 AM
Best response yet. This sounds like something I would have done as well minus the beer.

Reading this thread and several others has allowed me remember why I stopped visiting this forum at all. Too much bickering not enough machining content.

Where have all the level-headed kind people gone?


I made a small part for OP few years ago as a favor. Took me a few hrs time. I didn't charge anything but he did send a small cash token as a thank you. Covered my shipping and bought me a case of beer. Some sort of rocket part IIR

DATo
10-23-2011, 11:26 AM
I do too, but the last three are usually zeros.:D

*LMAO* .... that post should be put on the 'Favorite Jokes' thread. I love it !!!

vpt
10-23-2011, 11:27 AM
Harold said he will build the parts for $25!

Greg Parent
10-23-2011, 04:08 PM
A quick update...I have a person lined up to make the parts and would like to thank all those who offered here on the forum and on the PM system.

I would also like to thank all those who gave freely of their time and offered constructive criticism. I learned alot about how to make easier to machine parts, easier to understand drawings and what information is needed to transfer an idea to reality.

Thanks again.

Greg

Greg Parent
12-17-2011, 10:45 PM
Took a little while but here they are almost in service. There's some work to do on positioning and anchoring of the electronics but the bulkheads are just right.

http://img.photobucket.com/albums/0903/MuddyTires/DSCN4499.jpg

macona
12-18-2011, 12:40 AM
Took a little while but here they are almost in service. There's some work to do on positioning and anchoring of the electronics but the bulkheads are just right.

http://img.photobucket.com/albums/0903/MuddyTires/DSCN4499.jpg


Ahh. Altimeter for a model rocket. Friend at work just built an electronics bay for one of his rockets.

Greg Parent
12-18-2011, 02:57 PM
Ahh. Altimeter for a model rocket. Friend at work just built an electronics bay for one of his rockets.

Yes, it's a 250g capable Raven 2 by Featherweight Altimeters. The other board is a magnetic switch to turn everything on. There is going to be a mirror image of the same devices on the other side of the ebay sled. When ready it should fly on a K impulse motor that averages 2045ns. It should be a very quick ride to approximateely 12k feet.