Thumb notches.

[eveled]

I had it in my head to figure out how many TPI (teeth per inch) file Randall used to cut in the thumb notches. Just so I could clean them up from time to time.

I have three Randall’s with factory thumb notches and they are three different TPI. I would have thought they would have one that they used all the time. Oh well.

 

[tunefink]

They are hand cut, one by one on a wheel, just like the saw teeth. They will vary depending on the wheel wear.....saw teeth do as well.

 

[elmbow]

Every time I bone out or field dress a big game animal I have to spend a little time back at camp or home cleaning clotted blood, dried up collagen, and fat out of the thumb grooves and any other crevices. This is one of the reasons I don't like to use knives with handle scales that screw on for hunting because the screws and holes in the handles just create more cleaning work. What I have found works best is to take a piece of 2500 grit or finer sand paper, fold it in half and simply run it through the grooves after a quick soak in some hot soapy water. For the screw heads and such I use a gun cleaning pick with a barrel patch to pick out the dried up bits. If you are using your Randall's enough to require cleaning the thumb grooves I don't think you will create any additional wear using the sand paper method to clean them out, it is pretty hard to remove metal with 2500 grit or finer sand paper.

 

[eveled]

Thanks T tunefink I’m trying to wrap my head around how a worn out saw makes for a different spacing. I don’t doubt you because it explains the variations I just can’t picture it.

 

[eveled]

left (model23) ones aren’t flat you can see the reflection they are on two different planes.
Next (model19) are very fine but uniform.
Next (model 21) are coarser but uniform. Far right is my model 10/3. None of them are the same.

 

[tunefink]

Not a saw. An abrasive wheel.

 

[Melvin-Purvis]

I count all mine, and if they have more, or less than exactly twelve TPI, I sell 'em really quick like.