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Smokedaddy
05-13-2006, 03:29 AM
Hi,

Would apprecaite any suggestions on how to machine this part. It isn't that critical measurement wise, they are just motor covers for my telescope E/Q mount. Of course I want them to look like I knew what I was doing. Oh, it's aluminum and 1 3/4" in height. I'm still learning so take it easy on me with all the termnology and endmills needed. I do have a older BP and a rotary table (which I've never used yet).

http://www.pbase.com/smokedaddy/image/60089637/large

Thanks in advance,
-SD:

Millman
05-13-2006, 04:47 AM
SD, if you made all the parts in your gallery; I wouldn't think you need help to make that part. Fine work! Making that part should be a piece of cake. That looks like a heavy lathe also. Not knowing the dimensions...I would hog out the pocket first, cut the radii on the rotary or vice versa.

winchman
05-13-2006, 04:57 AM
If it's not critical, why not just make it round, instead of oblong. That way you could do it on a lathe with a boring bar. Use the mill to do the square hole as a second op.

Even if it has to be oblong, I'd do most of the material removal on a lathe. If it's circular with flattened sides, you can do it all on a lathe with a 4-jaw chuck.

I can't tell from the picture if it's a circle with two sides flattened or a rectangle with the ends radiused.

Roger

Millman
05-13-2006, 05:40 AM
SD, I used to build those high pressure stainless assemblies like that .....but YOUR tigging, would put mine to shame and I was good at the time. Makes me glad I'm retired and don't have to lust over beads like that. Excellent work.

torker
05-13-2006, 05:55 AM
What tig beads??? I flipped through the pics and I didn't see any. What did I miss?

Millman
05-13-2006, 06:05 AM
Click galleries, top left corner. I don't know for sure if that's SD's pics or not.

torker
05-13-2006, 09:06 AM
Ah..ok I see them. Up here you'd better be that good to work in the pulp mills.
The big joint done by the robot in the pics...we do them by hand. First couple are fun but after that it's pure drudgery.

BobWarfield
05-13-2006, 11:44 AM
Cool stuff. Looks like something for an Intel chip fab since one of the prints says "Intel". I like the sippy bottle full of alcohol. Too bad its Isopropyl! The gizmos that check the weld are cool too.

But there's more. Takahashi Hydrogen Alpha scope setup for viewing the sun, cool custom knives, motorcycles. Life is good there!

That part looks to me like it was made with CNC originally.

Best,

BW

Smokedaddy
05-13-2006, 05:12 PM
Hi,

Yes, I made everything you see in the gallery but it took me forever, and numerous attempts too. <grin> I still haven't finished my Domino jig either and this is my 3rd attempt.

http://www.pbase.com/smokedaddy/image/60113712

I'm still learning about Solar imaging. Still haven't prefected the technique but I'm getting pretty close. Hopefullyl I'll it nailed down in the next few months, weather and seeing conditions permiting.

http://www.pbase.com/smokedaddy/image/60113215

As far a the welding goes, those were high pressure (10,000psi) socket welds, all 100% x-ray (not that it was a big deal). It does take a lot of practice but that's all it is, practice. Below is a picture of a semi-conductor high-purity orbital weld (207 machine).

http://www.pbase.com/smokedaddy/image/14820901
http://www.pbase.com/smokedaddy/image/14820897
http://www.pbase.com/smokedaddy/image/14820903


and this one is a narrow groove diametric video welding machine we used on the nukes (Palo Verde).

http://www.pbase.com/smokedaddy/image/46174648
http://www.pbase.com/smokedaddy/image/46174648
http://www.pbase.com/smokedaddy/image/46228543

Okay, now back to my problem. <smile> I never thought about doing the operation on a lathe. Oh, no ... it can't be round. It must be as pictured. I can get the aluminum free, but can't get the experience free. <grin> I wasn't sure how to setup the rotary table since I've never used it.

Got'a go,
-SD:

winchman
05-13-2006, 07:25 PM
I made a sketch using an oblong with a length of 3" and a width of 2.5".

If you start with a 3" diameter and flatten two sides so the width is 2.5", the length of the flattenned side is about 1.6". The angle where the curve meets the flat is approximately 148 degrees.

If you start with a rectangle and do a full radius on both ends, the length of the flat is only 0.5 inch. The flat is tangent to the curve.

If you start with a 3" round, you can clamp it in the vise on the mill, take off a quarter inch, flip it over, and take off a quarter inch on the other side. Ease the corners with a little hand filing, and you're done with the outside.

If you start with a 3" x 2.5" rectangle, you need a long end mill to do the entire side in one pass. I'd guess a 1" diameter with a 2" length of cut would do it. Clamp the part to the RT with the center of the part offset .25" from the center of the RT. Cut the radius on one end (two corners), then offset the center .25" in the other direction for the other end.

I think I'd use the lathe, a 4-jaw chuck, and a boring bar to do the inside. Center the part to remove most of the material, then offset it .25" each way to get the ends. That'll leave you some minor bumps on the inside, but they probably won't be much.

I can't figure out an easy way to hold the part on the RT for machining the inside. Maybe you could mount the 4-jaw on the RT. That would give pretty good support and let you see the thickness of the sides as you work.

Roger

Smokedaddy
05-14-2006, 05:28 AM
Thanks Roger,

I knew it wouldn't be easy. Seems like everything I want to make is a PITA. <g>

-SD:

BobWarfield
05-15-2006, 11:45 AM
I can't figure out an easy way to hold the part on the RT for machining the inside. Maybe you could mount the 4-jaw on the RT. That would give pretty good support and let you see the thickness of the sides as you work.

Roger

If you cut the inside pocket first, you could use the holes to bolt the part to a fixture plate in order to do the outside.

BW

haaas
05-15-2006, 01:15 PM
If you have plenty of free material, I would mill out the basic length and width of the final part but leave about 1/4" extra on the thickness. Drill shallow locating holes at the center point of each arc opposite what will be the pocket. These would sit on a corresponding pin at the center of your RT(if you don't have this, that's your first project). You can clamp the part with one center located and cut your inside and outside arcs( a little at a time) and then with one point located on the outside flat, flip the part and cut the other remaining arcs. After the arcs are cut you can return the RT to 0 degrees(you did start at zero right) and cut the flats and remove the waste in the pocket. After all the rotary table work is finished you can remove the material with the locating holes in it and drill your holes and mill the box. Yes, clear as mud I'm sure. God bless CNC.
Good luck.

Millman
05-15-2006, 01:22 PM
Just how big is this part? After reading all the responses, I would hog out the OD dimensions, clamp it in a vise and plunge and finish the ID. The OD can then be dimensioned on a belt sander. Just how tight are the tolerances? There has to be some limits on all dimensions.

Evan
05-15-2006, 02:44 PM
Is there a reason you can't use round covers fastened to a flat adapter plate?

Millman
05-15-2006, 03:28 PM
Now see what I mean, Evan? That was a logical response to a question without all the Holier than thou, Potassium Poop, very good , young man!

Evan
05-15-2006, 04:30 PM
I have grandchildren in army cadets. Nobody has called me "young man" in quite a while.

John Stevenson
05-15-2006, 04:35 PM
Alright then how does 'Old Fart ' sound :D:D

{ all in good fun ]

.

Evan
05-15-2006, 04:41 PM
how does 'Old Fart ' sound
Sounds fine since both apply. :D

Smokedaddy
05-16-2006, 01:35 AM
Just how big is this part?

http://www.pbase.com/smokedaddy/image/60266872

-SD:

Smokedaddy
05-16-2006, 01:37 AM
Is there a reason you can't use round covers fastened to a flat adapter plate?

Hi Evan,

No I can't. The motor covers would hit the clutches on my mount.

-SD:

Smokedaddy
05-16-2006, 02:11 AM
If you have plenty of free material ......

haaas,

Humm ... I think I understand the concept. Sounds like a lot of work too. <grin> What would you suggest "specifically for endmills (or whatever) to do the outside and inside?

Would something like this work to do the pocketing, if I can find it the proper diameter and take light cuts. Not sure how chip removal would work either.

http://www.pbase.com/smokedaddy/image/57719835

-SD:

Evan
05-16-2006, 03:17 AM
The motor covers would hit the clutches on my mount.


Ok, how about rectangular on the outside and whatever provides enough clearance on the inside. It's easy to machine perfect looking flat surfaces on the outside in a lathe or a mill and I will presume that in use nobody can see the inside. :D

bob_s
05-16-2006, 10:11 AM
Love the .1 thou dimensioning information for a non-critical part!

ulav8r
05-16-2006, 10:43 AM
Bore 1 1/4 holes to remove material at ends, need boring head or fly cutter instead of rotary table. Then mill out center with end mill. Mill sides of outside, then cut end radii on a bandsaw and finish on a disk sander, or mill on the rotary table if you have an end mill that is long enough.

haaas
05-16-2006, 10:46 AM
SD-
As far as end mills to use, I guess I wouldn't try anything smaller than a 3/4 inch two flute end mill. Bigger is better. After thinking about it, I would mark the cuts and remove the majority of the pocket before cutting the arcs. Also, when clamping the part for the last operations I would recommend fitting the pocket with a tight fitting block(or an adjustable parallel) to resist the chances of crushing the part in the vise. Remember, More work=more experience.
Good luck.
fng

pcarpenter
05-16-2006, 04:31 PM
A tip in one of the Machinist's Bedside Readers for making radiuses on the ends of parts without a rotary table may apply here.

The illustration in the book is for the end of something that has a through hole in it, but your project may work as well.

You simply take a piece of round stock and set it across the top of your vise jaws and hang the part from it, clamp it in place and make a pass. You then loosen the jaws and pivot the piece on the round stock a bit and make another pass, pivot more and another pass, etc.. The diameter of the round stock and the location of the hole it passes through serves to define the center of the arc you are cutting on the outside of the part. You keep cutting flats across the width of the part until you have an arc. The more passes you make, the rounder it gets, but the premise is to cut some number of flats and then finish rounding it when you are done with a file...or better in this case...a belt sander. The belt sander is a great finishing tool for aluminum where the dimensions are not that critical.

The trouble in your case is that you would drill the inside of your part for the rod, but could not pass it all the way through. Still, all you need to do is to be able to "hang" your part on the round rod before tightening the vise jaws. I would make these locating holes in the part before hollowing out any of the rest of the interior, allowing you to make a temporary hole the exact diameter of the "hanger" bar and making the arc more accurate.

Paul

haaas
05-16-2006, 08:05 PM
SD-

To answer your question on the pictured mill, I think you want something with a spiral flute to help get the chips out of the way. There are many tools that I haven't tried and that looks like one of them. The boring-bar idea could also work. If you happen to have a 1-1/4" Dia. end mill you could forget the rotary table for the pocket and just make one quick pass. (just kidding)
Good luck.

-fng

Smokedaddy
05-16-2006, 09:47 PM
Love the .1 thou dimensioning information for a non-critical part!

Grin,

I had Autocad(s) dimensioning templete drawing setup that way ...

-SD:

winchman
05-16-2006, 11:35 PM
I don't see how this drawing:
http://www.pbase.com/smokedaddy/image/60266872

is going to give you a part which looks like this:
http://www.pbase.com/smokedaddy/image/60089637/large

Are you sure of the dimensions? Or, is the pictured part only similar to the one you want to make?

Roger

Smokedaddy
05-17-2006, 02:35 AM
Roger,

Yep, that's what I get for throwing something together. I updated the drawing. Maybe I got it right this time.

http://www.pbase.com/smokedaddy/image/60318643

Thanks,
-SD:

doctor demo
05-17-2006, 04:28 AM
Roger,

Yep, that's what I get for throwing something together. I updated the drawing. Maybe I got it right this time.

http://www.pbase.com/smokedaddy/image/60318643

Thanks,
-SD:
could you just make it out of flat stock, like a can is made then do a seam weld and weld a lid on it? take the whole thing to a belt sander andcall it done.
steve

bob_s
05-17-2006, 09:29 PM
fiberglass and epoxy over cardboard form