Vice repair- advice needed

[Jon Kerr]

Hi all,

I picked up this vice cheap on eBay. Unfortunately the photos are old- its now been fully wire brushed, oiled and is ready to go except one problem... the jaws.

The vice has removeable jaws. I have no idea if this is a modification, old repair, or original. I doubt its original.

When I bought it, the jaws had bolts in (1 missing), but the vice was seized shut. Once I got it unseized and cleaned it turns out these bolts were in a bad way (they certainly werent holding the jaws in much!)- the threads are mostly ruined and one of the holes is actually mangled and diagonal- I cant see how it ever had a bolt in it. Really strange.

 

My question is- what would you guys do to repair it?

I've tried drilling the hole out and tapping but its too tough without serious gear. I had no joy trying to drill the mangled hole out clean.

 

Would you weld the jaws back on?

I have no experience welding but am about to purchase a stick welder and gegt a friend to teach me. Would that be an appropriate fix?

 

I'm really hesitant as I dont want to ruin a really nice old vice, but its sat useless for the past few months since I cleaned it and I desperately need a solution.

[ThomasPowers]

Got any friends who work on big trucks or equipment and are used to fixing bad holes/bolts?

[Jon Kerr]

Unfortunately not

Is that the route you'd pursue though Thomas? Trying to fix the bolt holes?

 

[Kozzy]

Later vises did generally come with replaceable jaws.  That was standard on machine vises so they just carried it over to leg vises.  They have benefits in that you can use a hard flat, a hard checkered to really grab (and mar your part in most cases) or a soft brass to protect part surfaces.  

I'd personally replace them by fixing/tapping the screw holes..but I can't really see just how bad things are in the photos so don't know what you have to work with.  

You could also do smooth holes and just have dummy locating pins on the back of the replaceable jaws--that'd be easy to do with screws in that you just tap the threads in the replaceable jaws themselves to hold the countersunk screws and let the rest of the screw poke into the old holes (unthreaded) in the vise body.  A bit of screw location error provides some friction and they would need to be tapped into place to stay and could be tapped out pretty easily to change to soft jaws.

Note that you'd have to make your own jaws if you did the above.  It's not hard.

 

 

[Marc1]

Considering that a post vice is designed to forge on it, I wonder how well those screws will withstand hammering on the jaws. 

Of course for ordinary vice work, swapping jaws and replacing with different metals and surfaces is very handy. Not sure I would want that on my post vice. 

Having said that, I wouldn't modify what you have. Just repair it to original conditions by drilling and tapping for new screws. Not hard to do, lots of good advice in youtube for such procedure. 

If you then smash the screws when forging, you know you need a different post vice. 

[Anachronist58]

Mr. Kerr, please describe in detail, all difficulties encountered with the drill and tap operation. Include a description of:

the hardness or toughness of the removable jaws, and that of the holes in the vise body.

The size and depth of the threads you are trying to tap, and what are the troubles there?

Since you are increasing the thread size(?), that will cause an issue with the counterbore in the removable jaw.

Images of the features in question, are critical to solving your difficulties: both jaws, both faces.

I will follow this thread.

Robert Taylor

Edited December 2, 2019 by Anachronist58
addendum

[Jon Kerr]

Thanks for the replies everyone. I'll post some more pictures and details but I might not be able to get into the workshop till the weekend.

[Jon Kerr]

Had another go tonight. (Only had 20mins in the shop). Watched some YouTube videos about drilling steel earlier and followed the advice.

Having a new drill with better speed control and a better chuck helped. I made it through 1.5 holes before the battery died (and it was late anyway). Only openening them up from approx 6mm to 7mm, ready for an M8 tap, but it worked.

I also have a new tap wrench, which doesnt slip on the shank. So i managed to successfully tap the first hole out to M8.

I've attached pictures of the dodgy hole. Not sure how much success I'll have drilling this one. Any tips?

[SLAG]

Mr. J. Kerr,

I use high sulfur cutting oil for boring jobs in steel.

The oil helps clear the swarf from the hole.

It also cools the drill bit, and lengthens the time before I have to re-sharpen the bit.

A sharp bit is highly advisable.

SLAG.

[Marc1]

It is a patience game. Last time I replaced the elbow in my boat engine exhaust, I found one of the bolts had broken off and half of it was still in the hole after pulling it out. 

Drilled it out with progressively larger bits. In my case the forward section of the hole was stripped, so had to bore all the thread out, cut an oversized thread and screwed in an insert to bring it back to original. 

My suggestion is to use high tensile screws.

Those screws will take a beating, look at how the edge of the jaw body, rolled over the jaw insert from the hammering. 

[Irondragon Forge ClayWorks]

I would try fitting the jaw with the one hole you have tapped, tighten up the screw and clamp the side with the wonky hole then, use the hole in the jaw as a guide to drill the hole out and tap it.

[Anachronist58]

SLAG, I share your position, on oil, in general. Oil I believe, can cover a multitude of "sins".

If you wire brush the cutting edges of a brand new drill bit, it may hold up better. Science.

IDF&C, great advice.

Marc 1, good input. Thanks for reminding me about thread inserts, commonly referred to as Helicoils here in the States, depending upon trade.  That will be Jon Kerr's fallback solution.

Mr. Kerr, you are an ANIMAL for drilling that out by hand. Good on ya, Bob's your dad.

Many on this site are adept at this type of enterprise - easy for the elite, and a triumph for all others. It is obvious that you waded into the deep end, and got it done. I will consider the bad hole - looks like Marc 1's thread insert will be the answer. Have you worked out how the new screw size mates to the removable jaws? There are a number of options.

Robert Taylor

Edited December 4, 2019 by Anachronist58
addendum

[Jon Kerr]

Hi everyone,

Thanks for the tips and advice again!

SLAG- I've been using a tapping oil so far, for both drilling and tapping, just because I had it lying around. I was also going to try 3-in-1. I guess I high sulfur oil would be better? What does the sulfur do?

Marc- a helicoil is an option but I wanted to try and avoid it if possible. If I can get all the holes to M8 threads, I'll still have plenty of "meat" around the holes. I'm worried about that bad hole though and after your comments I actually wonder if its part of a bolt stuck in there, but its hard to tell. Maybe using successively larger bits as you say is that way to go?

IDF&C- great idea- will do exactly that when I come to drill the bad hole.

Anachronist- thanks! Yes it was a bit interesting without a pillar drill. As for the mating of the new screws... I work in an engineering company with an in-house workshop. Unfortunately modern Health and Safety rules prevent me from using most of the equipment in there, but occasionally the machinists will do me a favour. I've brought the vice jaws in with me today and will get them to increase the countersink size to suit an M8 screw flush.

My backup plan will be to lug the vice into the workshop and drill out any stubborn holes on the pillar drill, but I'm not sure how pleased my boss will be if he sees me!

 

[Jon Kerr]

Live update: The workshop are fixing the countersink in the removeable jaws  for me....

.... I got an email 20mins later to say the countersinking bits couldnt touch the steel as it was so hard!

I should have thought to check the hardness and annealed them before I took them in..!

I asked the workshop to have a go at annealing them with an oxy torch- I can always reharden them at home.

[pnut]

2 hours ago, Jon Kerr said:

I actually wonder if its part of a bolt stuck in there, but its hard to tell.

It looks like it to me but I have been wrong more often than not in cases like this. Progressively larger bits is my suggestion. 

Pnut

[Jon Kerr]

If it is, I have some bolt removal bits (basically just like a tap in opposition direction). If I drill a small hole I might be able to use that to extract the old bolt. Depends how badly rusted/seized it is.

[pnut]

My luck with those things has been hit or miss. I've gotten bolts out with them but usually have had to drill them out. You may have better luck with a drill press. I've always used hand drills with them and I think that may have been part of the problem.

Pnut

[Jon Kerr]

Further update: The workshop guys have given up. Whatever material those jaws were made from, its HARD! They tried annealing with a torch and it made no difference- must be air hardening steel.

I can possibly anneal them at home in vermiculite, but the guys are going to make me some new jaws from steel gauge plate for now. I owe them some cakes for their trouble!

Tonight I'll have a go at finishing drilling and tapping the holes....

[Anachronist58]

Jon Kerr, it appears to me that there is, indeed, a screw broken off in that one mangled hole. Try to extract it. If successful, the advantage would be having a pilot hole in true position.

Robert Taylor

Edited December 4, 2019 by Anachronist58
addendum

[ThomasPowers]

There are high grade drillbits that will drill hardened bolts; but you really need a large industrial sized drillpress in GREAT condition to get the feed and speed low enough and no wobble in the quill. Hand held drills just result in broken expensive drill bits.

[Marc1]

The problem with extracting broken bolts from a blind hole using a stud screw reverse extracto thingy, is that this things are hard ... and they are brittle. If you break one of them in the hole, good luck drilling it out. M8 is a very small size. Easy to break. 

I would keep on drilling and honestly I don't see how M8 even structural will perform long term under the hammer. You could go to M10, with no ill effect to the jaw body and have a beefier bolt in place. But I can be wrong. You need to careful measure the top of the wall and ponder if it will take the beating.

To me it seems that the right hole, the 'good' one is higher and has therefore less steel on top of the hole than the 'bad ' one. 

Of course you can take a pragmatic approach. Weld both holes shut. Drill and tap new M12 holes in a slightly lower position  ... and make new jaws to match. 

If I had to take this approach I would clean out both holes using a Die Grinder and carefully weld it shut with a stick welder, bit by bit, cleaning out the weld scale every time carefully even grinding the weld every time to avoid scale inclusions. Or TIG weld ? I don't have a TIG welder nor do I know how to. 

[Jon Kerr]

Hi all,

Thanks again for all the advice. Still working on this.

Tonight I succesfully finished drilling and tapping the 3 good holes.

I couldnt move onto the mangled hole as I want to use the jaws as a guide and I left them with the workshop guys.

I did try removing it with the "reverse tap extracto thingy" but couldnt get it to bite. I will try once more once I've drilled a small hole knowing the centre point, but I'm doubtful.

 

Thomas et al: are you saying I'm likely to not be able to drill out the bolt with a hand drill? (I have no experience doing so) Maybe I need to take it to the workshop pillar drill.

Marc: I hear your concerns re/ M8..... at this stage I dont want to go further to try and move to M10/12, but I understand I'm taking a risk. At my current smithing skill level I'm not likely to be doing very heavy work on it for a while anyway.

[ThomasPowers]

The harder the drill bit the more necessary it is to have a good rigid drill holding it.  Breaking a hardened bit or even a solid carbide bit in the hole would incline one towards spark erosion systems... 

[Anachronist58]

Agree Thomas in overwhelmingly most cases. I have been called upon to fix the unfixable under production pressure, and although I have been (mostly) successful, I still resent being put in that position. Next stop: EDM "Popper"!

You >can< use a carbide bit in a hand drill, but you have to do very special things to the twist drill and your approach. This is posted as a last-resort option, if you find yourself painted into that odious corner.

On 12/2/2019 at 10:18 AM, Jon Kerr said:

I've tried drilling the hole out and tapping but its too tough without serious gear.

Look how far you have come since you began this excursion!

Robert Taylor

Edited December 5, 2019 by Anachronist58
Post Assembly

[swedefiddle]

Good Morning,

I saw an Allen set screw in the bottom of the damaged hole. They are hard and difficult to drill. Use a Drill Press or a Mill/Drill at very slow speed. When you get the hole drilled through (go right through, not a dead hole), tap for a Heli-Coil or machine  for a bushing from a larger Grade 5 or better bolt (drill and tap the larger bolt in a Metal Lathe, to your desired inside size (8mm??). Cut the bolt to the desired length and you now have a Bushing. Perspective is not cast in Stone. The jaws are sitting on a ledge, on each side of the Jaws, the set screws only hold the Jaw to the Ledge, they don't take the abuse.

Don't drill the bad hole with a Hand Drill, unless you want to make the problem worse. NEVER USE an E-ZE-OUT!!!!! An easy-out will make your problem worse by expanding the stuck piece and locking it in forever. Then the E-ZE-Out will brake and you throw the whole Vice in the scrap. No Lesson Learned!!

Neil