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recoilless
07-17-2008, 01:44 PM
Had a small job done at local machine / fab shop. A couple weeks ago, I asked them if they could thread both ends of a 1" dia. piece of O-1 steel. The threads were to be a double start 7 tpi 7/8" major dia. I just needed 1" of threads on either end. I told them I'd supply mat'l which I centered, turned to major/minor diameter and gave them a drawing. I said I needed a price, owner ( neighbor, friend of wife's side of family) said don't worry about it, I'll take care of it for you... I said I'll pay you, since he wouldn't give a price I suggested $70. Two weeks later,I went to pick it up and he wanted $100. Said he had to send it out to get it done.

I paid him his $100 which I believe to be a bit on the high side of fair. Price wise, is this fair? I'm thinking shop rates are around $50-75/hr in this area(NW Indiana)

MickeyD
07-17-2008, 02:11 PM
I remember cutting them in school. A guy showed me a trick with shimming the tool over in the holder and after that it was as easy as could be. That does sound a little pricey for basically cutting 4 threads.

pcarpenter
07-17-2008, 03:07 PM
I wonder if you paid an hourly rate for a "current generation" machinist to learn to cut double-start threads:rolleyes:

Either way, if he was going to have to send it out making it subject to someone else's shop rates, you should have been told in advance. Its been my experience that some guys who are good machinists have poor business skills and a small operator really needs to be good at both.

I know a guy around here who is working in the $75/hour range as I recall. He is generally busier than a one-armed paper hanger because he will tackle smaller jobs and his rates are lower. Some of the rest of the bigger shops around here are up over $100/hour (central Illinois).

Me...I've never cut multi-start threads so I think I wouldn't do it for less than $100...it just sounds like a pain in the arse:D

Paul

John Stevenson
07-17-2008, 03:19 PM
Me...I've never cut multi-start threads so I think I wouldn't do it for less than $100...it just sounds like a pain in the arse:D

Paul

So if you have never cut multi start before why do you want $100 to learn at someones expense and material ?

Two start at 7 tpi means either special order tooling or grind your own up. Times this by 2 and you have the recipe for a lot of time wasting. Add in O1 as a material which doesn't help.

That job was roughly priced at 2 hours and in reality it would take about 1 - 1/2 to do it by the time tooling and setup was taken into account.
Allow another 1/2 hour for head scratching and it runs out about OK.

.

pcarpenter
07-17-2008, 03:31 PM
So if you have never cut multi start before why do you want $100 to learn at someones expense and material ?


I don't-- it was a joke. It does seem like a process requiring some care, however. I was really referencing my suggestion that perhaps the $100 (assuming his hourly rate assumptions were correct) came from someone who took longer to do it than an experienced machinist. Heck, the local shop had to farm it out...that says something about how many folks seem to know how to do this.

I had a retired research machinist from Caterpillar suggest to me that multi-start threads were an example of something that would probably get farmed out today (by Cat) as there has not been a real T&D apprentice program for long enough now that the folks who knew how to do more than basic stuff are all retired or dead.

Guys like you, John, are probably at an advantage....If you can't do it, who will? As such, you probably see more and know how to do far more because you handle so many things that are not even done by some machinists today. Being a jack of all trades can make you a master of all of them.
Paul

tattoomike68
07-17-2008, 03:59 PM
$100 sounds fair, not just anyone could whip it out.

miker
07-17-2008, 05:21 PM
MickeyD, could you please elaborate on the this comment...

"A guy showed me a trick with shimming the tool over in the holder and after that it was as easy as could be. "

Thanks

Rgds

ERBenoit
07-17-2008, 05:40 PM
$100 sounds fair, not just anyone could whip it out.

:rolleyes: I could. Multiple start threads are easy.

When the programming prompts for "# of starts", I just enter the number of starts when I write the program. :D

It's Simple.

I wouldn't want to do it the old way anymore.

quasi
07-17-2008, 05:51 PM
threading 0-1 is not much fun, at least for me.

Mark Hockett
07-17-2008, 09:14 PM
MickeyD, could you please elaborate on the this comment...

"A guy showed me a trick with shimming the tool over in the holder and after that it was as easy as could be. "

Thanks

Rgds
I think what he is saying is he moves the cutter to the side the distance of the thread pitch. As an example if you have a 8 tpi 2 start thread your thread pitch would be 1 divided by 8 which is .125" so you put a .125" shim next to your cutting tool and cut the next series of threads. This would be done with the machine set to cut 4 tpi.
If you wanted to cut an 8 tpi 4 start you would keep adding .125 shims for each thread start and set the machine to cut 2 tpi.

I still have to agree with ERBenoit I just program it and hit the start button.

mochinist
07-17-2008, 09:21 PM
$100 sounds fair, what wasn't fair is not giving a price before hand since you asked. I guess you could counterpoint that since he didnt give a price you could have just opted out, but he is a friend...

wierdscience
07-17-2008, 09:44 PM
Another vote for he should have told you,but the $100 is fair.

I could have done it in 45 minutes since my lathe runs a 3-1/2 pitch in the QC,but that would have been $45 and a three week wait,otherwise it would have been $90 for same day.

oldtiffie
07-17-2008, 10:47 PM
Weird and Mochinist have got it about right as regards the shop/contractor.

s I read it the Contractor did not give a price nor quote nor was he asked for one.

Premium time = accelerated job = premium rate.

No price/quote = "open-ended" cost/price on completion.

Many shops have a minimum as regards, charge, time or $/hour.

You'd have to expect to pay more for a "one off" as opposed to say 2, 4, 10 etc. as the "booking/administration" and set-up/tear-down times might well be about the same irrespective of the number of items to be done.

The Contactor is entitled to a fee for handling the job as he would have had to pay his (sub)Contractor who actully did the job.

He was quite in order to farm it out to someone else if he didn't have the time to do it "in house" in time.

There is nothing here to indicate that the Contractor could not do this screwing job - at all - just that - for his own reasons - that he "farmed it out".

How he gets it done and who he gets to do it is his right to choose, as all he has to do it get it done - unless he was specifically wanted or needed to do it personally.

Sometimes people don't want or need a job and just pull a "big number" out of the air as they "have to quote" as many think they have to quote on anything - don't know why because they don't. There is nothing wrong with refusing/declining to do a job or provide a quote either.

If the "big number" price/quote is accepted then he just has to get on with it as best he can.

Rich Carlstedt
07-18-2008, 12:44 AM
I bet He lost money on the deal .
For cutting 7 TPI double you can easily do a manual lathe setup that is not to bad.
Look at the threading dial as a clock. You use 6 or 12 oclock for the first thread, and 3 or 9 oclock marks for the second thread, all without a change in tooling or chuck.
The extra work, is that a standardd toolbit does not have enough side clearance for such a fast thread. Result ..custom toolbit.
You CNC guys amaze me....I have never seen a CNC job--one/two off-- cheaper than a manual !
The O1 and custom tool cost

Rich

Mark Hockett
07-18-2008, 03:22 AM
You CNC guys amaze me....I have never seen a CNC job--one/two off-- cheaper than a manual !
The O1 and custom tool cost

Rich

Rich,
Have you ever used a tool room CNC lathe? They are very fast for one offs, especially threading. On mine I can use an Aloris tool post and I have about 40 tool holders or I have an automatic tool turret for production work. Most of the common tools are usually set up in the offsets and ready to go. I just grab the tool, answer a few questions and hit start. How hard is it to cut a tapered pipe thread on a manual lathe? On my CNC lathe it is no harder to cut a tapered pipe thread than a straight thread.

Today I had to do a job that required a .124" bore X .140" deep with 3 degree tapered sides, 45 degree X .062" chamfer at the top and a .020" radius at the bottom. The customer sent me a DXF drawing which I loaded into my CAM system, clicked on the surfaces I wanted to machine, picked the tools and generated the tool paths. I used a .093" end mill to create the clearance bore for the .062" boring bar, so I only had to set up two tools. No special form tools were required and the final profile was cut in one continuous cut which left a perfect finish. This job also had tolerances of a few tenths, which would be difficult to hit on most manual lathes. I don't think any manual lathe would compete with that for time and accuracy. And when everything was said and done if the customer wants more its a simple process to pull up the file and run it.

oldtiffie
07-18-2008, 05:42 AM
Thanks Mark.

That was an interesting post - very.

After I read it I could see your points very well.

First of all a CAD file was probably used to generate the DXF file from which the CNC file was derived. It can be called up and modified as required. That is just the same as in any Engineering or Architectural professional office and even in some HSM shops.

[Edit]
I'd be surprised if the OP saved himself anything by providing his own material and pre-maching it. I'd guess he'd have done better just providing a sketch and notes and left the Contractors to select the material from their own stock which in turn suits both the machines/tooling and the OP/customers requirements.
[End edit]

So there is a lot of commonality there with the current states in many shops.

I can see that you have a very expensive and comprehensive tool investment and the capital and recurrent costs associated with it. That, as you say is largely if not entirely an advantage in efficiency as compared to the normal "manual" shop.

I was interested to see that in your web page that you seem to charge like an Accountant or Lawyer (sorry - no offence intended!!) - in 1/10 hour (6 minute) increments so I guess that with your "charge-out rate" that you would want as many chargeable units as possible. I was intrigued when I realised that you seem to have largely eliminated the "special" tools that seem endemic in a manual shop and that you just use a selection of pre-set tools.

I'd guess that your "machinists" are to a large extent "operators" who have a computer/CAD/CNC back-ground who need a lot less "machining" skills than many in a manual shop.

I'd think that the threads in the OP would not need a lead-screw as such - just a very good ball-screw that is not physically connected to the machine spindle at all but synchronised electronically as determined by the CNC system.

This in turn would eliminate half-nuts, threading dials, tool reliefs at the end of the thread or as is sometimes required on manual machines/lathes the leaving the half-nuts engaged and reversing the spindle. The slow speeds required for manual threading - particularly long/large thread leads and pitches - are also eliminated so that speed is dictated only by the capacity of the machine, the tools and the job. Futher, as the operator is sheilded from the cutting environment a much more aggressive cutting and coolant environment can be used than would be the case with "manual" machining.

In the case of the threading job in the OT, the contractor/shop who had the job would have a "win-win" situation if he sub-contracted the job/s to you who would get it made quickly, accurately and cheaply and make a profit and so would the "lead" contractor.

One thing that did strike me was that you with your very sophisticated and expensive equipment can and do very well in the "small jobbing" market which some may have thought - or hoped?? - would remain the sole - and only?? - domain of the "small manual shop".

Not so for them it seems as you and your ilk "have arrived" and are "breathing down their necks" (with your "hot burning breath"???).

I think that some here need to realise that this is the way of the present let alone the future.

John Stevenson
07-18-2008, 07:27 AM
Rich,
How hard is it to cut a tapered pipe thread on a manual lathe? On my CNC lathe it is no harder to cut a tapered pipe thread than a straight thread.


No harder to do on some of the ones I have worked,:D in fact it's often easier to do tapered when you want to do straight :D

.

John Stevenson
07-18-2008, 07:33 AM
First of all a CAD file was probably used to generate the DXF file from which the CNC file was derived. It can be called up and modified as required.

Not usually on most modern controllers, you get a conversational screen come up, usually a nice graphical screen and you just fill the blanks in.
No point saving one as it's so easy to do.

.

DR
07-18-2008, 08:41 AM
$100 was a bargain.

The shop owner/friend probably spent ten minutes talking with the OP. Then another ten minutes talking with the shop who actually did the work. All unproductive time, but none the less time away from "real" work.

I always tell people...assume a one man shop with $100/hour rate, try to do eight one hour jobs for eight different people in a day. Will you get rich? No, small jobs are time killers.

You could easily spent $100 just setting up the threading tool with correct clearance angle to cut a 3.5 tpi thread on 7/8" diameter (far from a standard type tool). The more I think about it, I wonder if the shop owner did this as a favor and lost money on it.

mochinist
07-18-2008, 09:25 AM
I'd be surprised if the OP saved himself anything by providing his own material and pre-maching it. I'd guess he'd have done better just providing a sketch and notes and left the Contractors to select the material from their own stock which in turn suits both the machines/tooling and the OP/customers requirements.Thats a habit I try and break of any new customers I get, they almost always end up costing themselves more money than if they would have just let me get the proper sized material and machine it the way I want to. I had one bring me in some knarled up piece of mystery aluminum last week, he was all happy that he saved $70 over the price for a similiar sized piece from a metal supplier. I spent atleast an extra 2 hours screwing with this chunk of aluminum getting it to size, so he really didnt save anything:)

Mark Hockett
07-18-2008, 11:27 AM
No harder to do on some of the ones I have worked,:D in fact it's often easier to do tapered when you want to do straight :D

.

John,
I have that problem on the CNC lathe sometimes. My CNC lathe has taper compensation in the control. If you are cutting a piece and you get taper caused by deflection or the tail stock out of alignment you can measure the difference at each end of the part, divide that by the length of the cut and input that number into the control and then it will cut perfectly straight. Thats all good until you start the next project and forget to clear the taper comp from the last job, oops.
I think of the time I used to spend just getting my tail stock in alignment, now I just type in a number and its magically in alignment

recoilless
07-18-2008, 01:12 PM
Well, thanks all for the responses. Bottom line is I paid because the job was done correctly and although I wasn't expecting to pay $100, I still did. As I said before, it was a bit more than I expected. $ 100 isn't going to send me into foreclosure. A few notes. It was done on a manual machine. I also made the point of saying it was NOT a rush job and it wasn't rushed as I picked up my product 2 weeks after I dropped off the material. My company has had the fab side of this outfit do a fair amount repairs on stone boxes, excavator buckets and the like. They do GREAT welding. I told the owner the dbl thread part was for me not my company and, as I said before, I expected to pay for it as I don't expect a freebie. Oh well, back to work.

Thanks.