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Author Topic: Slipjoint build along  (Read 372 times)

Online bjansen

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Slipjoint build along
« on: January 20, 2019, 08:52:18 PM »

A slipjoint build along -

I will use CPM154 stainless steel for the blade and spring, titanium for the liner material and black G10 for the scale material which is bought in sheet stock and cut to size on the bandsaw, then shaped on the grinder.   

Once the blade and spring are drilled, cut, stamped (makers mark) and shaped to rough size they are heat treated and tempered.   On this specific knife, I will use .005” washers on each side of the blade, thus I need to blade to be .010” to .0105 thinner than the spring.  I will then get the spring ground to the proper length so that it interacts with the blade in the perfect open position

My spring is .118 and the blade is about .1075 – perfect

I will then put the knife on a Ruple jig, to get tang shaped correctly.  This jig essentially measures the rise of the spring in the open, half stop and closed position.  It allows you to fine tune the tang such that in all positions, the spring is flush (i.e., the spring has the same rise when fully open, half closed and fully closed).

Once the tang is shaped, we can assemble the knife to make sure the blade position (when closed) is closing enough or correctly within the scales. I will then grind the back of the knife/blade to make it one seamless transition. 

On this particular knife, I am installing a shadow bushing.  This allows me to more effectively peen down the pivot pin in metal, rather than the G10 scale material.  To do so, I centered a .375 end mill on the scale and plunged down about .085.   I then cut and superglued in .375 nickel silver plugs.  Once those are dry and flat, I drill through the liner into the nickel silver.

Next, I will work on the shield.  I use a parser plate and dremel tool set up to route out the material for the shield.  On this slipjoint I am using a bullet shield. Once the shield is superglued in its space, I think take a 1/16” drill bit and drill through the shield and through the scale and then peen in a 1/16” 416 pin to secure it mechanically.

Next I will grind the blade.  To do this I will mark center lines on the blade using a scribe and a granite surface plate.  I will then grind to the lines on a 14” wheel on a 2x72 belt grinder. 

Once rough ground, I assemble the knife and make sure everything is centered. 

I will then hand sand the blade to 600 grit and then grind the swedges.  The swedges are then hand sanded to 600 grit as well.

Sanding the flats on a surface plate

Finished, hand sanded blade

Once everything is fit up, the scales are flat and the blade is ground/sanded we can then take everything apart and start the finish work.  I will round and finish sand the scales and put a finish on the liner material.  I will then sharpen the knife and put a final hand finish on the blade and the inside of the spring.  I will then use new washers, and cut pin stock to size.   Here is a picture  of all parts ready for the final peen. 

We then assemble and oil the knife and begin peening the pivot, then peen the back pin and finally the middle pin.  If everything is flat, there will not be any gaps in the knife. 

Once the peening is completed and the knife is functioning well, I will take a grinder and file and flush up the pin stock.     

A final sharpen and that baby is done.


  • Trad Bowhunter
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Re: Slipjoint build along
« Reply #1 on: January 20, 2019, 09:07:59 PM »
That's really amazing! Thanks for all the pictures and the explanations, great work as always!

Online bjansen

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Re: Slipjoint build along
« Reply #2 on: January 21, 2019, 08:43:51 AM »
Thanks Trapper

Offline Thadbow

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Re: Slipjoint build along
« Reply #3 on: January 21, 2019, 08:15:43 PM »
Great Work Brad!
« Last Edit: January 22, 2019, 06:06:17 AM by Thadbow »

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