Shim a Mill Vise Flat?

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mcman56
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Shim a Mill Vise Flat?

Post by mcman56 »

I had a previous post about getting material to sit flat in a vise. The responses prompted me to take a close look at the vise. I started by squaring the quill to < 0.0005 TIR to the table. I then squared the fixed jaw to the table travel <0.0005.
1. When I put an indicator on the floor of the vise and move it along the bottom, one side of the floor/ bottom is 0.003" higher than the other. This is over a travel of about 4 5/8". It looks perfectly flat front to back. I did check the bottom surface of the vise before installing. I thought that there may be something underneath so went around the outside with a 0.0015" feeler gage and found no gaps. Can something like this be shimmed flat or will it lose much of the rigidity by not sitting on the surface? For some reason it does just does not seem like a good idea.
2. The most surprising part is there there was about 0.010 slope from top to bottom of the fixed jaw. The jaw is about 2 3/8" tall. The bottom was tighter than the top so was probably biggest barrier to getting material flat. If I have a tool long enough, I'm assuming I can take a cut off the cast iron where the jaw bolts on. Hopefully it will not chatter too much.

I do appreciate all of the advice on vises and am looking into a replacement but this is what I have right now so need to make do. The price of a Kurt vise is hard to justify for this hobby and I see no used ones locally. It would be nice to know if some of the China made ones are worthwhile.
Vise 2.JPG
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NP317
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Re: Shim a Mill Vise Flat?

Post by NP317 »

Mount the vice directly to the table without the rotary base in place!
That might change all of your measurements.
THEN make your alignments.
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mcman56
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Re: Shim a Mill Vise Flat?

Post by mcman56 »

I did remove the rotary base prior to measurement. This was just an old picture to show what kind of vise it is. Does anyone know who made these?
John Evans
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Re: Shim a Mill Vise Flat?

Post by John Evans »

You can not make a silk purse out of a sow's ear. I have yet to see any import vise that is worth a dang. The ONLY good used vise I ever had was a Kurt. One of the worst was Brigdeport! Try shimming ! You do not have much to lose !! You might look into a tool maker's style vise like the 3" I recently sold if big enought.
PS Look at the Kurt web site in their scrach and dent area ,lots of times deals are there for cosmetic issues.
www.chaski.com
JBTR
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Re: Shim a Mill Vise Flat?

Post by JBTR »

I have that vise too. My dad got it with the Enco mill drill in 1983. I haven't used it much since I got a used 5" Kurt and refurbished it.

Those specs are about par for that vise. It was fine for the work my dad did at the time. If you need to shim, I don't think it's a problem if your shims are positioned for a stable rigid setup. You may be able to improve your numbers but don't expect perfection. My opinion.

You might want to investigate glacern.com. Their stuff looks interesting, grinding finished in U.S. Look for the free shipping code.

John
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Bill Shields
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Re: Shim a Mill Vise Flat?

Post by Bill Shields »

i use my BP vise for holding stuff that I heat with a torch for silver soldering....
Too many things going on to bother listing them.
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Harold_V
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Re: Shim a Mill Vise Flat?

Post by Harold_V »

You have NO HOPE of achieving functional work with a fixed jaw that is not perpendicular. You will struggle endlessly and lose confidence in your ability, thinking you are the problem when most likely you are not.

It will be a waste of your time to pursue that vise unless you first eliminate the perpendicularity error you reported. I would highly recommend that you begin alteration by placing the bed of the vise on parallels (that are truly parallel) then resurfacing the BASE of the vise until it provides 100% bearing. Once that has been accomplished, the fixed vise jaw should be removed and the mounting surface trued to 90°. Eliminate perpendicularity error to less than a maximum of a tenth/inch. All of this is best done with a surface grinder but careful work with a well squared head on a mill will suffice, although with slightly lower expectations.

Bridgeport vises. I purchased one with my first BP mill, new. I was then tasked with the need to square 5/8" leaded brass blocks with a half thou tolerance. The new BP vise was NOT capable of performing to that level. It was replaced with a Kurt, which is still in use to this day. That was more than 50 years ago. As much as I respect the BP mill (when used within its design parameters---it's no Kearney Trecker), I place no value on a BP vise, although I admire Bill's wisdom in using his for welding as he suggested.

One comment on shimming the vise base. Not a good idea. The base of a mill vise lends strength to its holding capacity. If you do anything to alter the interface between the vise and table, you can expect bowing of the vise when it is tightened. If you must shim, make sure they are full length and provided the needed support to prevent bowing.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
Wolfgang
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Re: Shim a Mill Vise Flat?

Post by Wolfgang »

Depending on the quality of your mill, clamp your vise, on good equal parallels, upside down on your mill and re-machine the bottom.
To square up the fixed jaw, remove the hardened plate and bolt the vise on your mill, aligned as you like it.
With as large a tungsten carbide end-milling cutter as you can fit into your spindle, re-machine the vertical face of the fixed jaw in a step-wise fashion: Machine only 1/4 of the milling cutter dia. at a time, raising the knee for successive cuts. Do this twice, with the second cut .003 to .004" depth of cut.
Prior to this tram the milling head so that it is as perfectly perpendicular to the table as you can make it. Better than .0005" run-out over 6" should be achievable.

The reason for the carbide milling cutter is that it deflects much less than any HSS cutter.

In a pinch a HSS cutter will serve, in which case I'd take 3 cuts, with the last 2 only about .002" deep.

It's not an ideal solution, but should provide with good and servicable results.

The final step would be to reduce the running clearance in the movable jaw to an absolute minimum. Also check it for perpendicularity, and correct as required.
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