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Chevy-SS
04-12-2007, 12:07 PM
Machinist-in-training here;

I have a small mill with a DRO, doing limited manufacturing of small parts. I want to speed up the process of machining down corners on some of these parts. Here's a pic of one of the parts. I have circled the corner in red. My question is: how can I jig this up so that I can just keep rotating the piece and quickly mill the next corner, identical depth to the other corners?

http://csgbenefits.org/cornerlink.jpg

thanks

ERBenoit
04-12-2007, 01:06 PM
First, you would need a fixture, not a jig. Fixtures are for work holding. Jigs guide cutting tools. (This is subject to debate, and has been here.) A chamfer cutter would be the easiest way to produce that angle, provided it is not some b*stard angle. It "appaers" to be 45*. Chamfer cutters are readily availiable in 45* and 60* angles.

Making a soft jaw for your vice would be an ideal fixture. Measure the width of the part from the base to the edge of the chamfer. Say that the part is 1/2" wide. The lower edge of the chamfer is 3/8" to the base of the part. Mill out a stepped section deep enough to accept the part, standing on it's long edge. The "back" and the "edge" of the step become your fixed reference. In this case, a step 5/16" deep should be plenty. This should provide you sufficient clearance for the cutter. Cutter clearance needs not be a huge amount, only enough to clear the cutter from the fixture. Relieve the lower corner(s) and back corner(s) in the jaw, so when you go to mill your first part, the yet to be removed corner(s), of the part have somewhere to set. Mill the step shallow enough that the vice will still tighten against the part. Once you get your X-Y 0-0 set, lock (if manual axes) the axis you will NOT be using, set and maintain your Z, or raise the knee (if applicable) to the achieve the appropriate depth. Start cycling the parts through.

There are many ways you could fixture that part. I looked at what you are attemping to do and figured how I would fixture that part in about .3 seconds.

As far as your "Machinist in training", opening, not sure about you skills and by no means knocking them, making a fixture for your application is a lot easier to go and do, than trying to describe "how to do". Experience will get you there.

Hope this makes sense and is of some help. Good luck.

NickH
04-12-2007, 01:08 PM
Set a vice at the correct angle to allow X or Y travel to make the cut on a part protruding from the vice.
Use a parallel if required to hold at the right height in the vice.
Use a separate stop to allow you to repeatably position the part, you could do this at the end not being machined if lengths are the same. Something as simple as a square with the handle clamped down to the table would suffice,
Regards,
Nick

Chevy-SS
04-12-2007, 01:45 PM
Fixture, got it...........

Thanks for the replies. I'm using a 45* dovetail cutter.

I'm kinda envisioning what you guys are describing.

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pcarpenter
04-12-2007, 02:43 PM
A fixture that would let you do the cut with an end mill should make the work cheaper too. Dovetail cutters are relatively expensive. If you hold it in a vise with the corner to be cut poiting up at the appropriate angle, the cut could all be done with the end of an end mill of the appropriate size by plunging, saving all table movement and any re-adjustment.

I don't know how critical the dimensions are on those corners, but a belt sander with a protractor slot and a stop clamped to the table could make them *really* fast to knock down.

Paul

CCWKen
04-12-2007, 02:46 PM
Welcome to the forum and don't be a stranger. In training or not, you've done a fine job of laying out that piece. Is it aluminum? We like pictures. :D

Chevy-SS
04-12-2007, 03:27 PM
Welcome to the forum and don't be a stranger. In training or not, you've done a fine job of laying out that piece. Is it aluminum? We like pictures. :D

Thanks for that. Yes, it's aluminum. I'm only working in alum and plastic for now.................

I got lots of questions. Hope you don't mind me posting them!

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mklotz
04-12-2007, 03:35 PM
I'd put a pin in a block such that when the part is mounted with the pin through the end hole in the part, the material to be cut hangs over the edge of the block. Two additional pins in the block serve as stops to orient the part at the correct angle to cut the chamfer. Lock the part in place with a quick acting clamp, cut chamfer, swing part to second pin, cut second chamfer. Reverse part end for end and repeat.

No dovetail cutter required and the vise doesn't have to be angled.

Chevy-SS
04-12-2007, 03:55 PM
I'd put a pin in a block such that when the part is mounted with the pin through the end hole in the part, the material to be cut hangs over the edge of the block. Two additional pins in the block serve as stops to orient the part at the correct angle to cut the chamfer. Lock the part in place with a quick acting clamp, cut chamfer, swing part to second pin, cut second chamfer. Reverse part end for end and repeat.

No dovetail cutter required and the vise doesn't have to be angled.

Yes, this sounds like good idea......................

C - ROSS
04-12-2007, 05:10 PM
Chevy SS

How about a radius on the corners?

Single pin, extension handle and then just swing it past any straight cutter. Flip and do the other end. Don't climb cut.

Good to see more new blood on the board, don't be a stranger and post lots of pictures.

Ross

agrip
04-12-2007, 07:26 PM
That is a job for someting like a horizontal mill and two 45^ straight cutters with a spacer in between.
You can do 10 -15 - 20 at a time.

Line em up, clamp em and run em thru. Flop over and feed thru again, done.


If you are adventurous, line em up and clamp within a flip flop jig, and use a table saw. Four zips and you're done.

Hth Ag

John Stevenson
04-12-2007, 07:33 PM
Nice post.
Six answers all plausible.
I was going to suggest the same as Agrips but after reading all the replies Marv's answer would suit me better.

Proves there 10 ways to skin a cat.............

.

Chevy-SS
04-12-2007, 07:33 PM
You guys have a lot of great ideas.

Muchos gracias!!!!

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lane
04-12-2007, 08:22 PM
I would clamp 5 are 6 of them together in the vise useing a stop on one end and with a end mill ground to 45 degrees cut one cornor flip and do the other . Turn them around and do other end . cutting 6 or so at a time.Keeping it no more than 3 inches thick . Part looks to be about 1/2 inch wide that being 6 parts.