Schrade 5Ot BrokenSpring Repair

[Jerlin]

Thanks for the prompt reply, Jeff. It all does make sense.
Your statement about retro-fitting a new blade and the hole size in the new blade being larger than the original blade is my situation. Therefore, I am going to need to make the bolster holes larger.
From what you indicated, the pivot pins should fit the blade hole with a little clearance, but should fit snugly in the bolster holes. That being the case, I'm thinking I should drill out the bolster holes to 13/64" (or possibly use a 20.637mm drill bit). Then machine the center portion of the pivot pin down slightly so the blade can move freely. Does that make sense?
For the other pins, I did try to match the size of the old pins when I took then out. However, as I said, the new pins are slightly loose in the holes. Maybe I'll just have to experiment until I have done a few and get the feel of things.
Best regards,

Jerry Johnson

[Jerlin]

Jeff, I just realized I made a huge mistake in converting inches to mm. It should be 5.159mm, not 20.637mm. I wasn't thinking.

Jerry

[Jeffinn]

Yikes, that’s quite a difference.
To give you a better idea about pin clearances look a the photo below. All of those pins could be easily installed by hand (no hammer needed during this phase). You should be able to rough fit your knife together on the bench by hand. Slide the other handle on and then check the knifes functionality. Keep it simple an it should be fine.

Jeff

[Jeffinn]

And a 5.159mm pin seems awfully large....
It seems like my 5ot pivot pins were in the 3mm range (3.2mm maybe?)

[Jeffinn]

I might have already asked you this, but what size is the hole in your blade?
Jeff

[Jerlin]

The hole in the new blade, which is a blank, is between 3/16" and 7/32". Therefore, I'm guessing 13/64". The hole in the new blade is larger than the hole in the original blade.

Jerry

[Jeffinn]

The blades with the 7/32" hole take an insert to allow for the use of a smaller pin.With the insert you'll use a 3.15 mm pin (which is probably close to what your bolster holes are).

[Jerlin]

Jeff, Any idea where I can find the insert? I have looked here locally and cannot find one the correct size.

Jerry Johnson

[Jerlin]

Jeff, I also could use a 3.15mm pin. Your suggestions are always appreciated.

Jerry Johnson

[Jeffinn]

For the blades that I have with the larger hole (.187” hole size) I used the bushings from USA knife maker. (Without having your blade in front of me I can’t say that your blade hole size is the same).
You can look at them here:
https://usaknifemaker.com/bushing-stain ... 6-oal.html
The ones in the link (And in my picture) are stainless steel, they also make them in brass. They have to be filed down a bit to get them to the correct thickness for your blade.
I know Dale and a few of the other guys bought tubing at the hardware store and cut some spacers from that. So that’s an option as well.
Jeff

[Jeffinn]

Here’s two different 5OT’s disassembled. One has the regular sized blade hole and the other has the enlarged hole:

A 3.15 mm pin fits in the bolster hole of either of these knives;

Here’s the two different blades, one with the large hole with a bushing installed and one that doesn’t need a bushing installed;

For the rest of the knife use pins that closely fit the holes.
Jeff

[Jerlin]

Jeff, I thought I had sent a reply shortly after you sent your last post. I must have done something wrong, because I do not see my reply to you. In any event, I greatly appreciate all the time you have devoted to me in getting my 50T back together. I did check out USA Knifemaker. Their bushing the size I need is about $2.25 each, plus about $11.00 for shipping. I wouldn't mind paying that much shipping if I had a larger order, but for a single $2.00 part, that is a little excessive.
I have a request of you that I would prefer to ask in a private message, if that is all right with you. Please let me know.

Jerry Johnson

[Jeffinn]

I sent you a private message.

[JonTerry]

got to follow this as I am going to attempt the same thing

[orvet]

One comment to Jerlin, when you need a hole that is between sizes in fractional bits, I always use number drills. They are +/- a few thousands difference between the fractional drills. It makes it much easier to get a hole that allows enough clearance for the pin to fit easily in the redrilled hole.

You can Google number drills and find out what their diameters are in thousands of an inch. I have a chart which I picked up at my local tools store, which gives me the diameters of all of the number drills from size 60 to size 1. You won't need a full index of number drills, just one that is the proper size for your task.

[OLDE CUTLER]

got to follow this as I am going to attempt the same thing

This is a years old thread by someone who has not been active in awhile, so there may not be an answer.

[Raccoon]

Is there a website that sells backsprings? If not, is there a place that sells the metal for them? I saw some for sale on eBay but they aren’t the exact ones I need. I am looking for something similar to pin stock that I can work with.

I am just getting started (wish me luck) in cleaning up some old knives I have and 4 have broken backsprings. This could be a rabbit hole I don’t know what I am in for.

Thanks for any help.

[OLDE CUTLER]

I have a spring stock assortment that is 1075 steel that I got from Brownells. Try their website. It is the assortment #149, and has 3/16" to 3/8" widths that works for double ended springs.

[Raccoon]

I did not see it on their website at this time but thank you for the suggestion. I suspect it’s best to buy a junk lot and and salvage from other knives.