Modifying a hardened Machine Vice

I have a small machine vice very similar to the Arc Euro Type 2 and I am now thinking of getting one with 98mm wide jaws.

Each side of the body has a groove to accept hold-down clamps. Unfortunately these grooves are not the full length of the body and I frequently find that I want to put a clamp where it wont go!

The vice is fully hardened and I wondered what would be the best way to extend the grooves. Even if the HRC50-55 steel was machinable with say, a carbide end mill I doubt my mill is man enough to make a good job of it.

One thought I had is to mount a thin cutting disk (angle grinder type) in the vertical mill spindle and cut a series of slits like the teeth of comb to remove the bulk of material and then break off the tines before cleaning up the groove bottom.

Ian P

If it works, this is a link to the type of vice

http://www.arceurotrade.co.uk/imagecache/d5ab730a-0fe3-4219-b327-a43000a3217b_700x204.jpg

I suggest that the makers did not extend the slots to the end for a good reason ...

Could you consider making a pair of hold-down slabs from plate to fit the slots, but longer, and with the corners machined away at 30 degrees or so, then you could clamp them down anywhere along the length of the slab. Just a thought.

Cheers, Tim

I would be curious to know what that good reason would be. The only thing I could think would be to save save money by reducing machining time.

From the product specification point of view the vice still has hold down grooves, its just that they could be better.

Although the groove looks to cover most of the length of the vice, in reality only the central area is full depth and usable for the clamps. Apart from the fact that good practice would dictate having the fixing points as far apart as possible, the part of the bed and side of the vice below the jaw opening are often needed to end-stops, jigs, or just to accommodate the shape of the workpiece.

Ian P

Hi Ian,

As already mentioned, make a special clamping plate to hold down the vice instead of modifying it. My vice only has a series of holes on the side and I made these plates which allow me to clamp in a number of different positions. The bolt holes could even be slots to allow an infinite number pf positions.

Paul.

This is how I attached mine to the Boley & Leinen jig borer.

And for really small stuff I do this

Phil

My suggestion about the slots not going to the ends is based on the idea that the ends are what resist the clamping load, and need all the strength they can muster. Continuing the slots outwards would surely weaken these areas?

Regards, Tim

If you are going to grind the groove out can you not profile the edge of the cutting disc to a V to match the groove ?

Martin

I appreciate all the suggestions for using the machine as it is supplied but its my own fault as in hindsight I should really have entitled the thread 'how to machine hardened steel?'

Paul nice drawing of his suggestions puts the clamps and the head of a bolt exactly where I want a clear area. In truth everybody uses their vice etc to suit the shape and size of the parts they are making and if the examples shown in the various replies work for their owners then that is all that matters.

I think the vice I have is actually intended for holding machined components purely for metrology purposes. It looks the same as the Arc type 2 and comes with an inspection certificate confirming its accuracy being ground on all surfaces with a high degree of flatness and squareness. Like the Ark vice it is presumably not intended for heavy work holding usage, if for no other reason than the fact that the clamping screw has a very coarse thread. The only difference between mine and the Arc vice is the 'keep plate' on the underside of the moving jaw has fully tightened bolts on mine whereas Arc's can be adjusted as required although in about seven years of frequent use and abuse there is no perceptible play or jaw lift on mine.

Martin. The groove is rectangular section, not Vee shaped.

Ian P

Hi Ian,

Just for clarification, looking at the size and description, I think you are referring to 98mm Type 3 on this page

I understand what Tim is saying too. So, I went and had a look at the 98mm Type 3. There seems to be enough meat to do what you are proposing, without compromisng on the rigidity.

Type 2 - which is also on the same page, has stots along the full length of the body.

Type 1 and 2 are made for a famous Taiwan brand by factory 'A'.

Type 3 - which you are considering, is made for a different famous Taiwan brand by factory 'B'.

Ketan at ARC.

Working all my life as an Injection mould toolmaker I have cut plenty of hardened steel. We got to the stage where we would rough out to around 2mm per face then harden to 52/54 HRC and finish after to eliminate distortion from hardening. Modern coated carbide cutters work well, keep as ridgid as possible don't be tempted to use big cutters 6/8mm for what you intend to do is fine. Keep the speed up and light pecks of around 0.010"/0.020" a fairly rapid feed rate so the carbide does not dwell and rub. Good eye protection is a must and may be gloves, the chips come off fast and hot.

Ketan

Yes you are right, it is the type 3 that I am going to purchase.

I bought the one I have privately and have no idea of its manufacturing origins, I'm certain it would have come from one of the famous factories you mention. Its certificate refers to the vice as QGG63 and its little handbook lists the vice applications as ideal for: 'precision measurement and inspection', 'precision grinding and spark eroding', with 'linear cutting machining' last in the list.

Regarding, the two cap screws holding the keep plate on the Type 3. Are these fitted with any sort of locking? If they are not meant to be fully tightened then in effect they are a sort of adjusting device and unless locked I can imagine they would creep and need regular adjusting.

Ian P

Chris

I must admit I had not thought of using a carbide endmill, I do know that it would probably work (I have one divot in the vice that I cut myself) so I can confirm its machinable!

I dont think my mill (Emco Mentor) is sufficiently rigid or man enough for this particular job, I'm tempted to have a go, after all the groove does not need to be very accurate or have a good surface finish.

Ian P

Hi Ian,

With that kind of reference, 'QGG63' it is a China factory 'A' reference for Type 3.

However, I do not buy the Type 3 from factory 'A'. I buy this specific type from factory 'B', because the nut/assembly for this particular type, where the screw enters the body, is better from factory 'B'.

Factory 'A' is a Mainland China sub-contractor for Vertex - Taiwan. As advised earlier, I buy Types 1 and 2 from this factory.

Factory 'B' is a Mainland China sub-contractor for Gin Chan - Taiwan. Link to page here.

Reference for Type 3 - 98mm wide is VSD40 on above page link. There is still a slite modification. The one we sell does not have the pointless hex-socket hole in the handle in the back. It has a hex nut in front of the handle, for this size.

The two cap screws holding the keep plate are not meant to be fully tightened.

At a packed weight of 11kg., it is HEAVY.

Ketan at ARC.

Edited By Ketan Swali on 01/12/2015 16:28:53

Edited By Ketan Swali on 01/12/2015 16:29:58