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Squareness - Milling Multiple Parts From Bar Stock

Cphockey16

Plastic
Joined
May 28, 2020
Hey there.

I've been a casual browser of practicalmachinist for close to a year now - or, right around the time I started my toolmaker apprenticeship. There's lots of great information here but I have one specific question I've been unable to find an answer to anywhere on the web.

So, I'm still running a Bridgeport most of the time at my shop. I've gotten to be pretty decent all-around as a manual mill-hand. However, most of the parts I've been making have been for prototype molds - I.E. - quantities of 2, 4, 6 etc. I've got a job coming up where I'll be making 40 parts and I'm looking for the most time savvy way to do it while still producing quality work.

My question is regarding squareness. Let's say I have a 2in x 2in x 6.5 in piece of steel and I want to make 10-14 parts from it. The parts finish dimensions are 2x2x0.4 thick. I have the part milled to completion on the height and width and each end of the length properly squared. I just need to cut off the appropriate size (say, at .45) and mill to my thickness. This is easy enough to do with the end pieces, the one machined surface allows me to complete the thickness while keeping things square all-around. My question is, is there any way to retain the squareness of my part when both sides of my thickness are saw-cut? Or do I need to run back to the mill and remachine the ends of my bar stock after I cut off each individual part?

Hopefully I described things well enough. Any help would be greatly appreciated!
 
If I understand you correctly, I would just work on cutting off from one end. After each "cut-off" operation run a mill across the end to square it up again and cut off the next one. Rinse and repeat until you run out of bar.

JMHO

-Ron
 
Yep. You understood me correctly. I figured I'd have to mill the bar stock again before cutting off each individual piece. I appreciate the quick response!

Dan
 
It's a simple enough piece, just a small foot to mill in and a single hole to drill. The boss doesn't want to tie up the cnc mills. I think it's in large part a test to see how efficiently I can do a larger quantity of parts before he moves me to the CNC. It might well be retarded but I couldn't say either way.
 
Do it in a different orientation if at all possible. Mill a few pieces to 2.00 X .40 X whatever long (depends on your workholding how long) and saw em up to 2.05 each. You will be left with a long enough edge to maintain squareness. Setup vise stop and go to town cleaning up ends.

Starting with 2.00 X 2.00 is a lot more work, and yes, I would mill ends square again if I HAD to do it that way.

Good luck with your career brother!
 
If I understand you correctly, I would just work on cutting off from one end. After each "cut-off" operation run a mill across the end to square it up again and cut off the next one. Rinse and repeat until you run out of bar.

JMHO

-Ron

You could save a little bit of time by doing them in pairs. Mill both ends of the bar square, cut off both ends to make two blanks, go back and mill both ends square again, repeat...
 
I kind of like this idea here. I'd hesitate to sidemill when I get down to the last few parts but one of the toolmakers recommended that I use gage blocks on the opposite end of the vise so there's equal pressure being exerted. Might have to give that a shot. Thanks!
 
A real suggestion this time. :)

Lay a grinding vise sideways in the bridgeport vise. Stick your bar in pointing up.
Facemill the end. Might be faster than side milling the bar.

I do end work like this all the time.
 
Just watch that the slices don’t warp when saw cutting them that thin!
 








 
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