Schrade 5Ot BrokenSpring Repair

[Jeffinn]

I received two 5OT’s from an AAPK friend as freebies. One was a green handle knife with a heavily worn blade and broken springs, the other was a brown handle knife with a decent blade but some ordinary handles.
I worked on a spring replacement/repair previously but the spring tension was too stiff so I put them away for a bit to work on other things.
This week I dug out the knifes again.
You can see in the photo of the springs (one on top of the other) that the end of the one of the springs is snapped off.

The 5OT’s use two of these springs in each knife. Both springs were broke in this knife one one spring was broke in the other.
I had previously purchased some spring stock from Jantz for a different project so I scrounged around in the shop until I found it.

The two original springs were about the same thickness as some nickel silver stock that I have so I decided to make a new rear knife spacer and cut a groove in it for the spring stock. The angle of the new spring doesn’t quite follow the old spring (you can see the outline of the old spring on the liner). But it seems to give enough tension to keep the lock bar in its correct position.

I cut and shaped the new nickel silver spacer to mimic the shape of the old springs. The groove for the spring stock was cut on my bandsaw. Once everything was roughly shaped in I reassembled the knife to make sure everything fit correctly.

The new spacer was just slightly thicker that I needed so I took it out to the belt sander and got it to the right thickness.
I temporarily clamped it all together to make sure everything looked right.

I decided to use the green handles because they looked to be in a little better condition. It turned out okay. I’d probably make a few changes to the repair procedure next time but as a concept it seems pretty solid.
The finished knife handles look dark in this picture but that’s because they were taken with my phone.

And since I didn’t have a dedicated buffing wheel for the brass bolsters, I polished them out buy hand with increasingly finer grits of sanding sticks.
It was a fun project. It didn’t turn out perfect but for a first attempt at this type of repair I’m happy with it.
Jeff

[doglegg]

Thanks for the walk through Jeff, I always enjoy your tours. And great job on the knife. Excellent!

[Doc B]

Nice engineering, Jeff!

[tinkerer]

That looks great!

[Meridian_Mike]

Good job Jeff!
That is good thinking to come up with an alternate spring method.
Looks nice! Great save!

[orvet]

Outstanding job Jeff!
That makes a good tutorial for anyone trying to replace the newer two flat springs in a Schrade lockback.
That works for the LB7, LB5, LB1, the 3OT, 5OT and the variations that do not use the liner lock.
I believe the 6OTX and 7OTX both use the flat springs and could be converted to the older style.


I thought I had posted a tutorial on replacing the two-piece Schrade Springs with the spacer and spring steel bar, but I can't find it. Yours will work even better!

If you are interested in the 5OT and its variants there is a pretty thorough study I did on that pattern in 2009. That topic also has an amazing collection of this pattern that belongs to Randy Coulter (W5RWU).
I have also most of the variants that I have collected to that pattern.
viewtopic.php?f=64&t=11428&p=94338&hilit=5ot#p94338

There's also a good discussion of the methods and repairing them posted in 2008.
viewtopic.php?f=37&t=9909&p=81780&hilit ... air#p81780

The discussion between myself, Muskrat Man, Adam (Darksev) and thawk on replacing the different styles is pretty good. It was probably buried so far that you would never have found it unless you know what term to search for.

Nice job my friend, keep up the good work!

[Jeffinn]

Outstanding job Jeff!
That makes a good tutorial for anyone trying to replace the newer two flat springs in a Schrade lockback.
That works for the LB7, LB5, LB1, the 3OT, 5OT and the variations that do not use the liner lock.
I believe the 6OTX and 7OTX both use the flat springs and could be converted to the older style.


I thought I had posted a tutorial on replacing the two-piece Schrade Springs with the spacer and spring steel bar, but I can't find it. Yours will work even better!

If you are interested in the 5OT and its variants there is a pretty thorough study I did on that pattern in 2009. That topic also has an amazing collection of this pattern that belongs to Randy Coulter (W5RWU).
I have also most of the variants that I have collected to that pattern.
viewtopic.php?f=64&t=11428&p=94338&hilit=5ot#p94338

There's also a good discussion of the methods and repairing them posted in 2008.
viewtopic.php?f=37&t=9909&p=81780&hilit ... air#p81780

The discussion between myself, Muskrat Man, Adam (Darksev) and thawk on replacing the different styles is pretty good. It was probably buried so far that you would never have found it unless you know what term to search for.

Nice job my friend, keep up the good work!

Thanks for the links Dale!
I’ll work on the other knife this week. I was looking through my spare blades drawers and came across a blade that looks like it’ll work as a replacement. It’s not marked 5ot, it’s just marked Schrade + U.S.A. LTD. I just did a quick test fit and it looks like it should work.

Jeff

[orvet]

If it doesn't fit I probably have one that will fit, maybe even one with the same tang stamp.

[Reverand]

That is an ingenius repair! Amd it will make any future spring replacements a breeze (hoping they are never needed though!)

[glennbad]

I love the ingenuity, great fix!

[muskrat man]

That is the best way to handle this type of repair and how I do it. I do dozens of these every year when Taylor/BTI/ Schrade forwards repair requests to me. It is the most common repair requested. Those double layer 1 piece springs were a bad idea, they were generally tempered too hard and being so thin they break easily. I have a pile of NOS springs for a couple different models but rarely use them because I have even had the new ones break within 5 minutes of completing the repair. A conventional leaf spring replacement is a MUCH better arrangement

[Jeffinn]

I noticed that this 5ot didn’t use a bushing in the blade pivot hole. The one I just took apart has a bushing. I just spent 30 minutes looking underneath my workbench for the bushing that I dropped (I finally found it).
Is there a source for those bushings? I’d like to have a few spares in my parts drawer in case I ever drop one and can’t find it.
Thanks.
Jeff

[muskrat man]

they could be made easily enough from brass rod of the correct diameter

[orvet]

I noticed that this 5ot didn’t use a bushing in the blade pivot hole. The one I just took apart has a bushing. I just spent 30 minutes looking underneath my workbench for the bushing that I dropped (I finally found it).
Is there a source for those bushings? I’d like to have a few spares in my parts drawer in case I ever drop one and can’t find it.
Thanks.
Jeff

Jeff, check out your local hardware store for stainless steel tubing. There are usually some 12 inch links there along with the brass pins stock and other pieces of metal. I have found them at both Ace Hardware and at True Value Hardware stores.
Measure the diameter of the hole you need and take your calipers with you to the hardware store and a piece of pin stock in it shouldn't take you long to find the right size tubing. I've been doing that for years on some of the models of the LB7 variations, but I think the LB5 may use a smaller diameter bushing.
Take the piece of tubing that's the right size home with you, cut it as close as you can get to the proper length, but leave a little bit longer so you can sand it down. I have a granite lapping block that is +/-0.002 that I used to lap the edges of the bushing I am making so that it is smooth. You can probably do the same thing with a piece of glass. I usually use 320 or 400 paper to start with and probably finish it with 600 wet or dry paper. I usually soak the paper pretty good with some WD-40 or a light machine oil to make it lap a little easier. If your bushing is 0.002" to 0.004" wider than the blade that can be a good thing because it will help keep the blade from binding when you peen the pivot pin.

I usually find it easier to cut the tubing close to the correct size if I use a small tubing cutter.
If you run into a snag, I believe you got my phone number give me a call.

The reason I use stainless steel tubing is because the bushings on the larger LB7 variance and some of the other knives are made from stainless steel.

[Jerlin]

Hi Jeff, I'm switching to this post, because the 50T you did in this post is what I would like to try to come up with on my 50T, but I know it will not be as good as your work. Fortunately the springs on mine were not broken.

I finally got the knife apart. The rear pins and backspring pin came out with the razor blade, but I ended up drilling the pivot pin out (it was made of steel and the razor blade would not cut it).

I have some questions at this point in my project. I have attached photos to try to illustrate some areas that I'm not sure about how to go about correcting.

1. How do you clean the brass liners and name plate?
2. Both bolsters have nicks and dings of varying degrees, especially on the handle without the name plate. How do you go about removing these nicks and dings?
3. How do you clean and polish the Delrin handles?
4. How do you polish the brass liners and name plate?
5. Should I wait on any of these steps until later in the project?

Thank you again for your willingness to help me with this project.

Delrin handles.

Liner side of handles.

Close up of pivot hole from liner side. Looks like bushings in center of hole.

Close up of bolster and pivot hole on name plate handle.

Close up of bolster and pivot hole on handle without name plate.

Close up of bolster end and pivot hole on handle without name plate.

Jerry Johnson

[Jeffinn]

Hi Jeff, I'm switching to this post, because the 50T you did in this post is what I would like to try to come up with on my 50T, but I know it will not be as good as your work. Fortunately the springs on mine were not broken.

I finally got the knife apart. The rear pins and backspring pin came out with the razor blade, but I ended up drilling the pivot pin out (it was made of steel and the razor blade would not cut it).

I have some questions at this point in my project. I have attached photos to try to illustrate some areas that I'm not sure about how to go about correcting.

1. How do you clean the brass liners and name plate?
2. Both bolsters have nicks and dings of varying degrees, especially on the handle without the name plate. How do you go about removing these nicks and dings?
3. How do you clean and polish the Delrin handles?
4. How do you polish the brass liners and name plate?
5. Should I wait on any of these steps until later in the project?

Thank you again for your willingness to help me with this project.

20200530_180438.jpg20200530_181053.jpg20200530_180916.jpg20200530_180536.jpg20200530_180644.jpg20200530_180800.jpg

Jerry Johnson

Hi Jerry,
Looks like you’re coming along nicely!
For the internal side of the brass liners I start out by giving them a light buffing with WD40 using a scotch brite pad. If there are deep grooves or gouges you can clean them up with different grit sandpaper’s. I usually start with 220 grit then go to 400 grit and finally 600 grit.
This process will work for the nicks and dings in the bolsters as well. If the dings and nicks are deep then you may need to use a file to lightly clean them up. I wrap my sandpaper around some flat sticks when cleaning up the bolsters to keep the surfaces fairly flat.
Polishing brass is similar to polishing any other metal. Start with a very fine grit paper (600 or 800 should be fine) then finish with polishing compound.
The delrin handles will polish up okay on your regular polishing wheel just be careful not to overheat the delrin. It usually doesn’t take a lot to bring them back to life.
You should start by cleaning the inside liners so they’re ready for you when you start to reassembly the knife. I usually give the bolsters a preliminary cleanup before I install the pivot pins but it’s something you can wait to do until after the pins are installed.
It does look like you have a blade bushing in the bolster in the one photo. Make sure you don’t lose that, it’s needed for the pivot pin to blade clearance. Make sure it doesn’t have any nicks in it that’ll prevent the pivot pin from rotating smoothly when installed. On my knife the bushing fits in the blade but yours may be different. Just make sure the bushing is in place when you reassemble everything.
You’ve got a lot of the hard work done. Now it’s just cleanup and reassembly work. Let me know if you have any other questions.
Have fun!
Jeff

[Jerlin]

Hi Jeff, Thank you for the very helpful advise and words of encouragement.
On closer examination, I'm pretty certain both bolsters have bushings in the pivot holes. The bushing that is difficult to see got roughened up from the razor blade. I believe the hole in that bushing also has some roughness. I assume I can run a drill bit the same size as the hole through it to smooth it out. Also, I just noticed the original blade does have a bushing in it. The hole in the replacement blade blank is larger than in the original blade and does not have a bushing. I will have to remove the bushing from the original blade, deburr it and install it in the new blade. Either that, or make a new bushing.
I have a couple of other questions. Does it matter if the sandpaper is used wet or dry? If wet, does it matter what liquid is used? Do you use any type of polishing compound when buffing the Delrin, or just the straight buffing wheel?

Best regards,

Jerry Johnson

[Jeffinn]

Hi Jeff, Thank you for the very helpful advise and words of encouragement.
On closer examination, I'm pretty certain both bolsters have bushings in the pivot holes. The bushing that is difficult to see got roughened up from the razor blade. I believe the hole in that bushing also has some roughness. I assume I can run a drill bit the same size as the hole through it to smooth it out. Also, I just noticed the original blade does have a bushing in it. The hole in the replacement blade blank is larger than in the original blade and does not have a bushing. I will have to remove the bushing from the original blade, deburr it and install it in the new blade. Either that, or make a new bushing.
I have a couple of other questions. Does it matter if the sandpaper is used wet or dry? If wet, does it matter what liquid is used? Do you use any type of polishing compound when buffing the Delrin, or just the straight buffing wheel?

Best regards,

Jerry Johnson

You can use the sandpaper wet or dry. I like using it with WD40 but I also use it dry. For polishing compound I usually use a compound called Black Magic or Pink No Scratch compound. Either one will work on delrin.
Jeff

[Jerlin]

Jeff, sorry to bother you on Sunday morning. I am between on line Bible study and our church service. I did a search on Black Magic. There are several Black Magic products. Could you please be more specific about which one you use. Thank you again for all your assistance.

Jerry Johnson

[Jeffinn]

Hi Jerry,
I use this compound and have had good luck with it: https://knifemaking.com/collections/pol ... lack-magic
Lots of folks use lots of different compounds and everyone has a favorite. This one is my standard “go to” compound for most of my polishing.
Have a great day!
Jeff

[Jerlin]

Hi Jeff, Thank you for the info on Black Magic.
Now I running into another snag regarding the pivot bushing. The bushing(s) are not in the handles as we thought. After I cleaned and polished the liners, the marks left by the bushing in the original blade disappeared. I tried driving the bushing out of the original blade, but with no success. Besides, the edge of the holes in the bushing on each side look slightly enlarged and damaged. I have attached some photos.
What was the bushing in your 50T made of? I know someone suggested using stainless steel tubing to make a new bushing. I believe they said the tubing could be obtained at Ace or True Value. I have not been to my stores yet. but hopefully I can find the tubing material. As far as I know, I'm just going to need the one bushing for the 50T I'm working on.
If I can get the bushing out of the original blade, do you think it could be used again? That is, if there is no more damage to it. If that is a possibility, do you have any suggestions on how to get the bushing out? Any other ideas would be greatly appreciated.

Kindest regards,

Jerry Johnson

Better side of bushing hole.

Better side of bushing hole.

Worst side of bushing hole.

Worst side of bushing hole.

[glennbad]

Are you sure that's a bushing? To me, it just looks like marks from something in the liners grinding against the blade. Of course, I could be wrong, just ask my wife...

[Jeffinn]

How big is the hole in the blade? Some of those knives used a bushing and some didn’t. The hole in the blade shown doesn’t look that large, it might not require a bushing. I believe the one I had without a bushing just used a 3mm pin.
Jeff

[Jerlin]

I'm using a new blade blank. The hole in it is 2.4mm or 3/32". Maybe I need to use a 3mm pin, but then I will need to drill out the holes in the bolsters. Is that what you did?

Jerry

[Jeffinn]

No, I would machine the pin to fit the hole. You should be able to machine a 2.5mm pin down to size to fit. Chuck the pin in a drill and use a file and/or sandpaper to get it down to the size you need.
Or find some 3/32” pin stock and use that.
Jeff