Blade centering on Slipjoints--argh!!

J

John L

Joined
Oct 28, 2004
Messages
1,330
I have read all the posts on drilling the perfect hole, have checked the blade before perining pins with two pcs of flatground stock, checked liners, etc, ad infinitum,....but I still cannot get any regular centering of closed blade in a slipjont. Some are perfect ..some just suck...ya never know. Anyone have this problem and fixed it? Someone said it could be uneven grinding..but this is not the problem either. Quite confusing and exasperating. Thanks.
 
Get a reamer and use it by hand instead of drill press or mill. helped me out alot whith that problem. I also drill the hole for the pin a size smaller than the reamer just to make sure.
 
If all your parts are dead flat and your grinds are dead even then either the hole isnt straight or your pinching the liners whith the assembly.Make sure your drill press is square.
 
I wasn't sure if by "flat ground stock" you meant "precision ground" stock.
You may already know this, but precision ground steel isn't precisely flat. It's only a precise thickness. You still have to flatten it.
Good luck :)
 
Hello McAhron: How would I pinch the liners? Don't quite understand. I use a piece of 1.5 thou shim stock on either side of the blade while peining and then remove...many times is very hard to remove. I think you may have something here as I have checked squareness of drill press, even grinding of both sides, parallel sides of blade, don't see how the liners would get out of parallel..though at this point anything is possible. How do you pein together? Thanks for everyones help.
 
Im by no means an expert but have done a few slippies for fun.One trick I learned from someone I cant remember is using shim stock with a channel cut out of it so when its placed into the knife for peening it completly surounds the pin and reduces the chance of pinching the liners,also not to over work the pivot pin.If the pin is hammered to much on one side it will pinch the liners.Another trick I got from the Centafonte,Lake book is releaving the liners around the pivot so it doesnt scratch the blade or pinch it.Use a micrometer and measure the liner gap from several places and that will tell you if the liners got bent during peening.I used bronze bushings as descrbed in the above mentioned book and the first one the blade wasnt centered and it ended up the bushing wasnt parrallel so on the next one I precision ground it.I notice with hand honing I tend to place more pressure on one side than the other.
 
The only way I have found to get the blade centered is to do the final grind after the pivot pin is peened. This can be a partial assemby using brass pins that you will drill out. Put the knife together, peen the pivot and butt pins, (not the center spring pin) and then do the final grind and move the tip the direction you need to make it center. If you check closely it will be a very small amount and chances are your grind is not perfectly straight which also makes the blade look off center.

I does help to make sure your drill press is plum to the table when drilling I do this by pivoting a dial indicator in the chuck.
 
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