How Would You Make This Part?

Well, rahcheer on/in this ng we have a fellow who is, on numerous levels, a swindler who cain't lube a spindle (except for maybe his own), and whose credibility has done dwindled to zero a long time ago.

Whose brain might not fill up a thimble.

Is there a lyricist in the house?

You mean, you jb-proofed it? Proly he'd screw it up anyway, out of spite.

Hi Bob. Just wandering. Could you have checked the wall thickness before taking the part of and adjust it? Also something about the washers. You can get small aluminum washers for pop rivets. They would be great for this kind of work and you would not have to worry about damaging your cutter. Nice work. Jerry

Jerry wrote:

Jerry:

Good point. Actually, I did check the walls before I pulled it off, and noticed the centers were fat. And yes, I could have made some extra programming passes, but they would have to have been heavy in the middle and tapering off on the ends. I decided it was easier, faster and more accurate in the long run to add supporting pins in the area that was deflecting. Plus this little holding fixture might have to be used again in the future if they want a couple more of these puppies.

Yep, aluminum washers would have been better, but I couldn't wait a day for delivery. This particular problem has not arisen before, but I should probably order some alum 4-40 washers - just in case for the future. Good point Jerry.

Why thank you.

*IF* I had more of these to do (like anything over 10), I'd probably use 5/32" dowels in the larger holes and hold the parts down with thin aluminum clamps around perimeter.

Just another OPINION while I'm here, wire EDM'ing would do the perimeter, but you'd still have to make a locating fixture to do the upper and lower "notches". So if you're going to make a fixture anyway, you may as well make the the whole part with it and not have to worry about outside processing matching your existing holes, being off center etc.

Oh, here's something I didn't add in the original explanation. There was a .050 thick strip that "appeared" to screw on the front my part. It's kind of like the back wall reproduced and attached to the front by the edge 4-40 Heli-Coiled holes. Well after my part was done, which had 1/16" radii next to the Heli-Coils, as per the model/print, the strip had square corners - as per the model/print for THAT part. But the strip wouldn't fit flush with my part due to the radii holding it off. Now we didn't have an assembly drawing/model showing just how, or even IF, the strip actually mounted to my part. It just looked to me like it should. A few job shops would just ship the parts as is, since they were made to print. But we often save the engineers bacon by catching boo-boos before they are shipped, preferably before they are reproduced in metal. So we called the engineer about the possible problem, and if it WAS a problem we would offer two solutions. Either radius the ends of the strip, or square the corners where the strip contacts "my" part. Yes, it WAS a problem, and they chose the squaring the corners solution. So I used basically the same setup I used for doing the edge holes but I had to lift the part above the vise jaws. I didn't want to just rest the part on top of a pin, I wanted to hold the part by the side of the .030 front lip for better support. I just happened to have a 2" long 1/2" wide hardened strip that had a .010 relief in the middle, so I put that on the top of the jaws and raised the part until it contacted the relief. That made the part sit .010 above the vise jaws while being held by about .020 of the rest of the lip.

I don't know if ANY of that last part was really understandable. As you all know, this is what every machinist goes through day after day, week after week, as a matter of course. It seems that when written out, you've got to write a book length explanation on how to tap a simple hole. LOL

Great work, Bob. 3 ring binder worthy for sure. How much did the part move in the 6 inch dimension after being released from the fixture?

Joe:

Thanks. I don't know if it qualifies as a machining tip, it was just a quick and dirty setup. Tom Brewer sent me some zip files this morning that show an excellent way to make these things in production, I hope he posts them.

As far as moving, the walls came out pretty straight, but the part was really flexible. A little tweaking brought in the dimension between the "pincers". It was going to be sandwiched between top and bottom flat plates (which were made by a couple of other guys in the shop), with screws going through all pieces. Plus, a front strip. So the assembly was sort of self-aligning.

Here ya go;

First operation complete

Pocket milled in jaws

Loaded for second operation

Second operation complete

Loaded for third and last operation

Part Complete

Unloading completed part

For a production run I would make tooling to run multiple parts complete, exactly how would be determined by job quantity, machines & tooling available.

Tom

Wow.....

What program did you use for this? Did you draw the vise, or is the vise a kind of intra-program clipart?

I ackshooly learned sumpn! Good show!

======== Very nice. Thanks for closing the loop.

Unka' George [George McDuffee]

------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).

SolidWorks

What "loop" would that be?

Jon Banquer San Diego, CA