New Points for Old Gauge

[Stew Hagerty]

I have a very old mortified gauge by Mathieson & Son that is in excellent condition except that the inside pin was either worn down or broken off and the outside one has been filed down to match it.

I also cannot remove the screw that holds in the outside pin. Whoever filed the pin also ended up filing some of the head down on it as well.

I am no good whatsoever with metalworking and new pins need to be brazed in. Can anyone help me out? I'd really like to get this put back into working condition.

[Bill Houghton]

I'm sure it is mortified*, being unable to do its work (insert smiley face).

Are you sure they're brazed? My impression of most of those pins on mortise gauges is that they're just driven into a perfectly sized hole. I've heard of people using the shanks of properly sized drill bits for replacements, although I'd check first that you can file the piece before you insert it.

*from Dictionary.com: "to humiliate or shame, as by injury to one's pride or self-respect."

[Jim Koepke]

Stew,

Pictures help immensely when helping others solve problems.

If the screw is a round head and you are willing to replace it instead of reuse it there may be an easy way to get it out.

If you have a pair of regular wire cutters (commonly called diagonal pliers or "dikes") you can use the blade tips to pinch across the head of the screw head and start to turn counter clockwise to remove the screw. The axis of the screw and of the center of the tool will be the same.

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There are other ways others may be able to suggest.

As Bill suggests, in my experience these pins are usually a press fit, not brazed or welded. That doesn't mean someone didn't mistreat your gauge in the past.

jtk

[Stew Hagerty]

I'm sure it is mortified*, being unable to do its work (insert smiley face).

Are you sure they're brazed? My impression of most of those pins on mortise gauges is that they're just driven into a perfectly sized hole. I've heard of people using the shanks of properly sized drill bits for replacements, although I'd check first that you can file the piece before you insert it.

*from Dictionary.com: "to humiliate or shame, as by injury to one's pride or self-respect."


Stew,

Pictures help immensely when helping others solve problems.

If the screw is a round head and you are willing to replace it instead of reuse it there may be an easy way to get it out.

If you have a pair of regular wire cutters (commonly called diagonal pliers or "dikes") you can use the blade tips to pinch across the head of the screw head and start to turn counter clockwise to remove the screw. The axis of the screw and of the center of the tool will be the same.

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There are other ways others may be able to suggest.

As Bill suggests, in my experience these pins are usually a press fit, not brazed or welded. That doesn't mean someone didn't mistreat your gauge in the past.

jtk

I will take a couple of photos tomorrow and post them. They certainly look as though they have been brazed into the brass rods, but like I said, I know next to nothing about metal working. As for the "dykes" that would work except that the head is flush and there is enough filed off that there is very little evidence of a slot left.

[Jim Koepke]

As for the "dykes" that would work except that the head is flush and there is enough filed off that there is very little evidence of a slot left.

In this case a dremel tool might be the answer if you can cut a slot in the head to aid in removal.

This could damage the head if you are not real careful.

There are also left hand drill bits available just for the purpose of removing stuck screws. McMaster Carr used to carry them. You have to have a drill motor that can run in reverse.

In some cases you might be able to solder a brass rod to the screw and use that to remove the screw.

jtk

[Steve Bates]

Glad to read there's a slot remaining, Stew. That tells me it's threaded. I've used a sharp pointed, hardened punch to unscrew. Using a steel hammer to strike the punch to obtain the shock and vibration to loosen thread, angle punch to obtain direction of travel to unscrew. Don't place punch mark near outer circumference, screw may be flathead (tapered) and/or the punch mark may deform circumference increasing resistance to move. I've had good luck with 2/3 to 3/4 distance from center to circumference.

Using penetrating oil to loosen rust, crud, dried oil/grease prior to mechanical loosening helps. Allowing time to penetrate help also.

Looking forward to reading about your success. Please keep us posted.

My two pennies

[Bill Houghton]

Is there enough metal remaining in the slide and fixed pin location just to drill new holes for new pins?

[Stew Hagerty]

Alright. I finally got some photos. Now, they're hard to make out, and I'm not sure that the photos show exactly what my eyes are seeing. However, it still looks to me like the pins might be brazed in. Tell me what you all think. Oh, and what is the best thing to use for replacement pins ?



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[Jim Koepke]

Stew,

It looks like someone went a little overboard with a file to sharpen those in the past.

If this were mine I would consider trying to replace the brass pieces if possible.

Seeing the back side is necessary to see if they are actually brazed in.

Can you get the screw out on the outside pin?

If so how does the pin look on the back side. Not sure how yours works, but my recollection is mine has to be taken apart to get the screw adjusted pin bar to come out.

jtk

[Stew Hagerty]

Stew,

It looks like someone went a little overboard with a file to sharpen those in the past.

If this were mine I would consider trying to replace the brass pieces if possible.

Seeing the back side is necessary to see if they are actually brazed in.

Can you get the screw out on the outside pin?

If so how does the pin look on the back side. Not sure how yours works, but my recollection is mine has to be taken apart to get the screw adjusted pin bar to come out.

jtk

Ah, Jim... Trust you to come up with something so obvious I didn't see it.

I just went out to the workshop and pulled out the movable bar and got a real good look at the pin, including the back side. It is indeed pressed in, I think it just looked like it may have been brazed because of the file troughs on each side from some over zealous sharpening. Interestingly, the points are very sharp and, even though short, marked quite well.

So, the next questions are:

1 - Since I still need to get out the stationary bar, what is the best way to get out that old screw?
2 - How to get out the old pins?
3 - Do I just use a small punch & hammer?
4 - And with what do I replace them?

Photos:

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[Jim Koepke]

So, the next questions are:

1 - Since I still need to get out the stationary bar, what is the best way to get out that old screw?
2 - How to get out the old pins?
3 - Do I just use a small punch & hammer?
4 - And with what do I replace them?


Not being on scene makes it difficult to make a "this should work" conclusion for removing the screw. I will get back to this.

Let's start with the pin removal from the first piece.

There needs to be a way to hold the piece securely atop something to support the area around the pin. I always keep scraps of steel tubing and other things to sacrifice for this kind of work. If need be a small vise can support the brass with the jaws open wide enough to allow the pin to be punched out. One important consideration is to be able to capture the pin. This is so you can measure it to make your new pin. I also save old broken drill bits just for such times. (My father gave me my pack rat genes.)

This sounds more complicated than it really is.

Basically support the holder. Drive the pin out with a punch that is smaller than the pin diameter. Make sure you are set up to not let the pin get away.

For some reason this reminds me of my days as a bicycle mechanic and the little tool we used to drive out a pin from a link in a bicycle chain. If you had one of these and could grind the pin to size it would be "the tool to use." Google > bicycle chain tool < and select images and you will see what I mean. It wouldn't be real hard to make something like this is one had the time and inclination.

Okay back to getting the screw out. My first order of business on such a challenge is to secure the piece in a vise or other holding set up so I do not have to worry about it moving.

Hopefully you have no attachment to this fastener of such consternation.

Remember the battle cry, "onward with lefty loosey and righty tighty!"

The following methods should work whether the screw is made of steel or brass. After writing below it came to me that you may have a left hand threaded screw. That is very unlikely, but if you get something in the slot and the screw doesn't want to move one way, give it a try the other. I do not know if anyone ever made left hand thread wood screws, but anything could be possible.

My order of removal is to try the ways meant by the makers of any fastener. Then if need be get creative in ways of removal. Finally if the only solution is to drill it out, then that is what will be done.

From your pictures it looks like there is a little slot left. I can get down right creative when making a thin blade from a 16d nail pounded out and filed smooth held by vise grip pliers to turn such a screw. Sometimes it is possible to carefully recut a slot with a dremel tool.

If there is any metal above the surface that would be my next approach to gripping the screw with pliers.

Next with the item held firmly I would try a trick from my old days working on automobiles. Using a small sharp chisel (the type for metal, not wood) lodge it in the little bit of slot left as close to the outside edge as possible and lightly tap it with a small hammer. If you do not have a small chisel, make one out of a nail. All you need is a sharp point to grab the material you are trying to move. Make sure you are going in a counter clockwise direction. The chisel, tool, should be held at as low of an angle as is possible to transfer the force into the screw head.

If the screw still refuses to budge drilling may be your only hope. There are a few steps to this method. First is to drill just enough to get what is called an eze-out into the screw head. If you do not have an eze-out, you may be able to grind the end of a nail square and drive it into the hole made by the drill. This works best with a brass screw.

The ugly side of drilling a wood screw is if you use too big of a bit you will remove the head and leave the shank in the wood.

This is a place where I would seriously consider investing in some of these:

http://www.mcmaster.com/#left-hand-drill-bits/=rakbjz

Of course the best place to use them would be on a drill press. This means you would have to know how to rewire an ac motor to make it go backwards. For most motors it is just installing a jumper.

Good luck and let us know how it goes.

jtk

[Bill Houghton]

I'll add to Jim's comments that, if you can find feeler gauge stock the right size, that works even better than a nail: stronger steel.

[Stew Hagerty]

Well Alright!

I fixed it!

I used a chisel to slowly spin out the screw until I could get hold of it with some pliers. Then I punched out the old pins with a tiny nail set. They were 9/128ths so I used a 5/64ths bit to make 2 new pins. While I had it apart, I filed the top of the brass rods to get rid of all the old file marks. I tapped in the new pins, angled faces towards each other, until approximately 1/4" was exposed. Here's the result:



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[Fitzhugh Freeman]

Ah, I just went through this myself yesterday with the same exact model gauge - my mom had it on a shelf as a decoration (she has good taste) - turns out it was my grandfather's and she came across it in a box recently. Luckily she gave it up without a fight, though she did NOT give up the antique dovetail saw which hangs on the wall in her kitchen. Oh well, I'll try again.

Anyhow, the pins are just press fit. I managed to tap one out enough to make up a small difference in height so as to avoid filing the other down, something like 1/32. I just stuck the business side of the pin in a small hole drilled in a piece of hard wood so the brass bar was flat on the wood and gave my punch-replacement taps with a hammer until it moved a tiny bit. That confirms it wasn't brazed, at least. Said punch-replacement was a wood screw I had in reach - ground off the threads from the last bit and ground the end flat but still smaller than the pin. I was just moving it a tiny bit and it not work in your case.

The screw is steel, 1/2 inch long, and normal direction threads. It also came out with little difficulty, though some of the others were harder (namely the ones holding on the brass plate that the lock screw sits in, and which I only realized didn't need removing after all once I had removed them and messed one up a bit). I don't have calipers but I'll measure the width of the screw shank best I can and post some photos shortly. If you find it really helpful I'll round up some calipers and measure the screw and the pin, and verify the screw pitch. Just let me know.

[Fitzhugh Freeman]

Not sure if this helps, but it might if you need to drill or replace the screw. I'll take the screw to the HW store and measure it if you find you need it.
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[Fitzhugh Freeman]

Wow, you must have hit submit right as I did. Congrats!

Now, I have a question:

What is the best way to sharpen these? A sharp/acute angled cone? a flattened cone? don't be so picky, just make sure they hurt when you grab the wrong end? Thanks.

[Stew Hagerty]

Wow, you must have hit submit right as I did. Congrats!

Now, I have a question:

What is the best way to sharpen these? A sharp/acute angled cone? a flattened cone? don't be so picky, just make sure they hurt when you grab the wrong end? Thanks.

Thanks...

Well I sharpened these by beveling one side then lightly filing the rest of the pin until it was nice and sharp. Then face the angled sides towards each other. This gives the outside of the scored line a sharper edge, while the inside of the line doesn't matter. That's the way I learned it anyway. And it makes some sense.