Coining or Milling liners on a slipjoint, Sheffeild style.

ken erickson · May 23, 2012

I recently posted a picture of a slipjoint with coined liners and was asked if I could show my method for achieving this look.

This operation is quite simple but does require that the knife is just about finished.

Tools needed;

Knurling wheel, available from many tools suppliers. The one I use is 50 TPI with a .250 center hole. While mine has slanted lines, they are available with 90 degree lines also.

Some sort of mandrel or two sided handle for the knurling wheel to spin on. I just used a piece of .250 round stock, but I may make a holder with wooden handles. It would offer a bit more control.

Padded vice to hold the liner stable while coining.

The pictures are pretty much self explanatory.

While coining a brass liner in the pictures I had sitting around I use this same method on 410 stainless steel liners with equal results. I take the liners to at at least a 400 grit or finer. After coining I finish up with a 800 to 1000 grit backed up with something hard as to not wash out the coining.

I am sure I may have missed something here, please feel free to ask any questions you may have!

Raymond Richard · May 23, 2012

I had often wondered how the coining was achieved. Never knew it was so simple. Thanks!

ken erickson · May 23, 2012

Raymond Richard said:
I had often wondered how the coining was achieved. Never knew it was so simple. Thanks!

Same here Raymond! I neglected to pass on thanks to Richard Rogers for sharing this method with me. Thanks Richard:thumbup:

woodwrkr221 · May 23, 2012

Thanks Ken, that's a great detail!

Is more than one pass needed with the knurling wheel when coining either brass or 410 stainless? If so, how do you make sure the knurling wheel stays in the grooves made by the previous pass?

ken erickson · May 23, 2012

woodwrkr221 said:
Thanks Ken, that's a great detail!

Is more than one pass needed with the knurling wheel when coining either brass or 410 stainless? If so, how do you make sure the knurling wheel stays in the grooves made by the previous pass?

More than one pass is necessary on both materials. It is very easy to pick up a line already cut with the wheel. A bit of thumb pressure on the wheel and very slowly,with light pressure, drag it across the liner and it will fall into a previously cut line. I do use moderate to heavy downward pressure when rolling the wheel.

Bill DeShivs · May 23, 2012

You can also use millgrain wheels for different patterns.
I use a checkering file, but it only works well on flat or convex surfaces.

12345678910 · May 23, 2012

Wont that push material from the edge and become wider at each coining groove

Do you have to resand the flats flat again ?

When you say you "finish up with a 800 to 1000 grit " do you mean that you sand the top of the edge you just coined?

ken erickson · May 23, 2012

12345678910 said:
Wont that push material from the edge and become wider at each coining groove

Do you have to resand the flats flat again ?

When you say you "finish up with a 800 to 1000 grit " do you mean that you sand the top of the edge you just coined?

The coining process will push out tiny burrs which I simply will knock off with a fine stone, then finish the sides of the liners as I normally would.

After I fully assemble the knife I go over the coined edges with 800 or 1000 grit as my final finish.

Salem Straub · May 24, 2012

Thanks Ken, that's a good tip. I'd previously only known of the checkering file way, this looks like a great method to try.