Jimping by machine, need bit advice

[MKaiser]

I just completed a small run of knives and I'm trying to find a precise way to do the jimping as I don't really trust my hand with a file, not to mention it would be a ton of hand filing. I'm doing four grooves on the back of the blade where your thumb would go and I need precise depth and spacing. I was going to try doing this with my drill press with some type of 1/8" cutting/abrasive bit, a fence and an 1/8" drill bit embedded in the fence for indexing. But what type of bit should I use for cutting the jimping? Any advice? I've seen some Dermel bits that might work, but if anyone has any suggestions it would be much appreciated.

[White Rabbit]

you could use a metal cutting bandsaw and touch it up with a needle file. or depending on your drill press and if you have a good vise for it you could just try drilling notches on the spine a little bit more than half a bit width wide.

Personally, I still think filing by hand is easier, and you could probably work up a rig pretty easily that would make more precise cuts.

[Mark Redmon]

Checkering files work well for this.

http://www.brownells.com/.aspx/pid=4...ECKERING_FILES

[MKaiser]

I've thought about making a jig with a file and a brass rod mounted side by side, then using the brass rod as a guide after making the first cut. This is probably the cheapest way to go.

The checkering files look like a good idea too, I'll have to look into that.

Thanks.

[White Rabbit]

What I'd probably do for a jig is clamp the knife by the tang in a vise so the blade is sticking up. Then take a rectangular needle file and sand the teeth off on the wide sides so there are only teeth on the end. Then just lay the wide side on the top of the vise so it lays flat and next to the spine where you want the jimping. Then just start filing away and move the knife up or down when you want to change spots.

[Nathan the Machinist]

This would be done in industry with crush grinding. You could do something similar by dressing a bench grinder stone with some grooves, leaving high spots in the profile, then grind your design into the spine in one wack.

[Chris Meyer]

I too would go with the checkering files. They cut quickly and give nice parallel lines. You select the file by the number of lines per inch you want. By the way, MidwayUSA sells the files cheaper. I don't know if they are the same brand.

[Mace]

I have never heard the term "jimping" pertaining to knives.(Actually I've never heard the term jimping referring to anything) Is this a machining term, or is this a knife term?
Just curious.
Mace

[Nathan the Machinist]

I have never heard the term "jimping" pertaining to knives.(Actually I've never heard the term jimping referring to anything) Is this a machining term, or is this a knife term?
Just curious.
Mace

Hey Mace,

I have only ever heard it used in reference to a knife. It ain't a machining term. It is the cuts or ridges on the spine of a knife to provide traction for your thumb.

[sunshadow]

My grandfather used to call any filework on the spine of a knife "jimping"

-Page

[Fred.Rowe]

Jimping; I have a new word to add to my vocabulary.


At first look I thought it was a misspell.

Fred

[Edro20]

I first heard the word "jimping" on a YouTube video review of a Chris Reeve knife. I didn't know if this was a "real" knife term or not. Either way I know what the OP is talking about now.

[jawilder]

I have heard that you can take a metal cutting circular saw blade and mount it on your bench grinder. If you get several blades and separate them with spacers you should be able to grind all of your slots at once and evenly.

I have not tried it tho.

[Chris Meyer]

Man, you guys have got to get up to speed on your straight razor lingo. Jimps (or jimping) is what the groves on tang are called. They look good and help give you a better grip.

These are factory jimps on a new Dovo razor.



And these are some I added to an old Wade & Butcher with a checkering file.