Holding Round Stock in a Vice

Nerdlinger · Apr 14, 2020

Hi Everyone!

I need to lop one of the round edges off a 1-1/2" round 4140 PH (30HRC) bar, about 2" long. Please see the attached picture. The dotted green line is where I need to cut to. The machine is a 30-taper dual contact Speedio and the vice is a 6" Kurt hydraulic vice.

1. Is it fine to hold round stock just on flat walls of a vice or should I taper them like I did in the pic? I thought a 10 degree taper would help keep the part from pulling up?

2. On a small machine like a Speedio is the best way to remove that material still just with a face mill? A part of me thinks it might actually be faster to do a zig zag thing with like a 1/2" end mill and then leave .005" for a finish pass with a face mill. I've never been terribly confident with my 30-taper's ability to hog off material with a face mill...

Thank you!

johneezreno · Apr 14, 2020

Well how many thousands of parts will you be putting flats on? Modifications to vice jaws always very on the job. Just a couple pieces, put the part in and give it a dead blow tap to make sure it's sitting flat. Maybe add a parallel under it to feel for slip. As far as a shell mill vs a 1/2" mill, it all depends on the diameter vs # of inserts vs insert style. Going to MSC or Kennametal can give you many options, and recommendations. Again. Just a few, throw in a carbide mill and get r done. Thousands of parts..... do the research.
Good luck.

Sent from my SM-G950U using Tapatalk

michiganbuck · Apr 14, 2020

If altering a jaw for a long production run part, then altering the fixed jaw only may be best.

This so not tending to lift the moving jaw..

Cutting forces. like rotation of cutter and the like favoring those forces toward the solid jaw side on the vise.

D.D.Machine · Apr 14, 2020

Aluminum jaws are your friend .. aluminum to steel is something like 5 tims the grip of steel to steel .

I run some production parts all the time in alum jaws and push a 40 taper as hard as I can and have never had one move yet ,,

I would do a stock removal by going around the od of the part and just leave like .015 for a finish face cut ,,, 3/8" endmills are a lot cheaper than 1/2" and you can still get a lot done with them.

Nerdlinger · Apr 14, 2020

johneezreno said:
Well how many thousands of parts will you be putting flats on? Modifications to vice jaws always very on the job. Just a couple pieces, put the part in and give it a dead blow tap to make sure it's sitting flat. Maybe add a parallel under it to feel for slip. As far as a shell mill vs a 1/2" mill, it all depends on the diameter vs # of inserts vs insert style. Going to MSC or Kennametal can give you many options, and recommendations. Again. Just a few, throw in a carbide mill and get r done. Thousands of parts..... do the research.
Good luck.

Sent from my SM-G950U using Tapatalk

Thank you for the response! Tens of thousands each year.

Nerdlinger · Apr 14, 2020

D.D.Machine said:
Aluminum jaws are your friend .. aluminum to steel is something like 5 tims the grip of steel to steel .

Wow, I never knew that! If I go with AL jaws would you say I could just make them with straight sides and be sure the first several clamping are done with the stock all the way down so little wear marks form in the right spot and then rely on those little pockets/divots to help keep the part down in the future?

Wsurfer · Apr 15, 2020

Sure looks ideal geometry for a face mill, but I've only cut (303,304) ss steel with an end mill on my brother (non dual contact). I hog aluminum regularly with a 2" ripper mill, but have yet to get a face mill for steel. Hopefully Brotherfrank will jump in.

Either way report back on what you end up doing.

AARONT · Apr 15, 2020

Are the ends saw cut? If the ends are faced, you could just rotate them 90° and clamp on the ends. Then use a shell mill cutting towards the fixed jaw. Or one part on each side of the vise and side mill them with an endmill if you're worried about running a face mill in your 30 taper. Otherwise clamping on the diameter will be fine, however you may have to dial back on the aggressiveness of the cut. You will also want to watch clamping pressure unless flats on the OD from clamping doesn't matter.

Goff · Apr 15, 2020

Make the fixed jaw like a horizontal V-block. The angle doesn't matter, just enough to clear your cutter.
The moving jaw is just a standard jaw. You get 3 point contact and repeatability.

BROTHERFRANK · Apr 15, 2020

With that quantity there is a lot to consider here. Are the blanks saw cut so the ends are not consistent and parallel? How is the OD of the material? I definitely like the idea of some taper in the fixed jaw, maybe make them out of 7075 for more durability. As far as material removal, I am thinking a high feed style face mill (1.5" to 2") and then a finish pass with another finishing face mill. With the high feed, you will take off about .025" or .030" at a time at about 350 to 400 IPM. Less air cutting than a high speed tool path with a 3/8. If you were trying to take an inch off, then the 3/8 would probably win with an efficient tool path... Check with your tooling rep for a high feed recommendation. I've used the Mitsubishi AJX successfully.

Nerdlinger · Apr 15, 2020

AARONT said:
Are the ends saw cut? If the ends are faced, you could just rotate them 90° and clamp on the ends. Then use a shell mill cutting towards the fixed jaw. Or one part on each side of the vise and side mill them with an endmill if you're worried about running a face mill in your 30 taper. Otherwise clamping on the diameter will be fine, however you may have to dial back on the aggressiveness of the cut. You will also want to watch clamping pressure unless flats on the OD from clamping doesn't matter.

Thanks! The ends ARE saw cut. I like your idea of holding two parts in each jaw with the ?chord? hanging over the side and using an end mill, but I suppose that won't work with the saw-cut ends. So clamping on the diameter with straight-wall vice jaws, tapered, and/or aluminum or steel?

Oh and I have a question regarding cutting direction and trying to get the cutting forces to go against the fixed jaw. Does one 1) feed FROM the movable jaw TOWARDS the fixed jaw, in which case the TOOL is approaching the fixed jaw perpendicularly but the rotating teeth are moving more-or-less parallel to the jaw if you are going straight down the center of the part, or even pulling the part AWAY from the fixed jaw if your climb milling with a low stepover. It seems to me like you might actually want to move the tool parallel to the fixed jaw with the jaw on the right side of the cutter so the rotating teeth are pushing the material toward the fixed jaw, even though the FEED of the tool is parallel to it. Does that make any sense or am I totally thinking about it the wrong way? :crazy:

Thank you!

Nerdlinger · Apr 15, 2020

jcoehlo said:
Make the fixed jaw like a horizontal V-block. The angle doesn't matter, just enough to clear your cutter.
The moving jaw is just a standard jaw. You get 3 point contact and repeatability.

That makes sense! Thanks!

Nerdlinger · Apr 15, 2020

BROTHERFRANK said:
With that quantity there is a lot to consider here. Are the blanks saw cut so the ends are not consistent and parallel? How is the OD of the material? I definitely like the idea of some taper in the fixed jaw, maybe make them out of 7075 for more durability. As far as material removal, I am thinking a high feed style face mill (1.5" to 2") and then a finish pass with another finishing face mill. With the high feed, you will take off about .025" or .030" at a time at about 350 to 400 IPM. Less air cutting than a high speed tool path with a 3/8. If you were trying to take an inch off, then the 3/8 would probably win with an efficient tool path... Check with your tooling rep for a high feed recommendation. I've used the Mitsubishi AJX successfully.

Thanks, Frank! I know essentially nothing about aluminium other than how to spell it... Is it standard-enough practice to hold steel parts with aluminum jaws? I was always under the impression they would just get beat-the-hell up in no time but maybe not with this "7075" you're suggesting.

The parts are saw cut but the OD looks polished (maybe that's normal for pre-hard 4140?)

TeachMePlease · Apr 15, 2020

Rather than a facemill, I'd use one of these at like 30% RDOC and .010" off the finished face ADOC and just rip around the thing, then finish that last .010 with your facemill.

Helical Tool You should look to see if they have a shorter flute length (I'm sure they do)... This is just the exact tool I have, so I could find it quickly with Google.

Nerdlinger · Apr 15, 2020

TeachMePlease said:
Rather than a facemill, I'd use one of these at like 30% RDOC and .010" off the finished face ADOC and just rip around the thing, then finish that last .010 with your facemill.

Helical Tool You should look to see if they have a shorter flute length (I'm sure they do)... This is just the exact tool I have, so I could find it quickly with Google.

Thanks! As fun as it would be to go 400IPM with a 2" face mill I'm not sure I have the balls for that. I think I would feel much more comfortable zipping around with an em like you suggested. It sounds like BOTH would work, though. Thanks!

AARONT · Apr 15, 2020

Nerdlinger said:
Thanks! The ends ARE saw cut. I like your idea of holding two parts in each jaw with the ?chord? hanging over the side and using an end mill, but I suppose that won't work with the saw-cut ends. So clamping on the diameter with straight-wall vice jaws, tapered, and/or aluminum or steel?

Oh and I have a question regarding cutting direction and trying to get the cutting forces to go against the fixed jaw. Does one 1) feed FROM the movable jaw TOWARDS the fixed jaw, in which case the TOOL is approaching the fixed jaw perpendicularly but the rotating teeth are moving more-or-less parallel to the jaw if you are going straight down the center of the part, or even pulling the part AWAY from the fixed jaw if your climb milling with a low stepover. It seems to me like you might actually want to move the tool parallel to the fixed jaw with the jaw on the right side of the cutter so the rotating teeth are pushing the material toward the fixed jaw, even though the FEED of the tool is parallel to it. Does that make any sense or am I totally thinking about it the wrong way?

Thank you!

I don't think it would matter much if holding the diameter. If you're holding the ends and using a facemill, you would want to feed into the hard jaw. Depending on the tolerance needed for the part. You may be able to use serrated pads(like this McMaster-Carr )on the ends of a soft jaw. It would allow you to still clamp on the ends of the part and side mill.

Mtndew · Apr 15, 2020

Yep make your jaw a Vee jaw and you'll be fine. I have a matched pair that I made a while back specifically for parts like this.

Nerdlinger · Apr 15, 2020

Mtndew said:
Yep make your jaw a Vee jaw and you'll be fine. I have a matched pair that I made a while back specifically for parts like this.

So does the part rest on the floor and then "rise up" into the V upon clamping?

Mtndew · Apr 15, 2020

Nerdlinger said:
So does the part rest on the floor and then "rise up" into the V upon clamping?

On the parts I originally made it for, yes. It was only 3/4" dia stock.

DavidScott · Apr 15, 2020

For thousands, I would cut radiuses in the soft jaws with a little relief in the bottom of the radius to ensure good contact with the parts, and go to town with a face mill with 45-degree positive rake inserts. But this is all academic as we don't know the tolerances you have to meet, or how many thousands of parts, or how many vises you want to use at a time.

Also aluminum has about 2.3 times the coefficient of friction as steel.

Holding Round Stock in a Vice

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