Milling Black Linen Micarta

[watercrawl]

Need some advice, please....before I ruin another piece of micarta.

I'm making a ferrule for a kitchen knife and decided to try and make it from two pieces of 1/2" black linen micarta. I was to trace the tang shape onto each piece of micarta, then use the mill to remove half the width of the tang from both pieces of micarta, then glue them together. All worked famously. I got the tightest fitting ferrules I've done thus far....I was happy.

Then I went to mill out the nipple on the ferrule that will form a mechanical connection to the body of the rest of the handle...the nipple fits into the body as you can probably presume from the attached picture.

The problem comes when I mill this material I'm getting chip outs along the edge of the piece. I'm using a 1/4" HSS, 4 flute milling bit and I've tried anywhere from 500 rpm to 1,200 rpm with no luck. At first, the bit was brand new....so it was quite sharp. I have another bit, but I don't want to dull it practicing again.

Any advice is greatly appreciated.

The piece is approximately 1" tall x 3/4" wide x 1.5" long. The seam doesn't seem to be the problem...the chipping is along all of the edges.

 

[Nathan the Machinist]

Yup, it will do that, but don't worry, the fix is easy.

1st, climb mill. That way the cutter is pushing the material back into the work piece instead of trying to pull it out.
2nd, if possible change your order of operations so the upper area is cut first, that way chips are removed in the second operation.
3rd, leave room for some finish cuts on the bottom. A couple light cuts at the end can remove little chips without making more.
4th, this is a good application for aluminum specific endmills. They generate less cutting force than a regular general purpose cutter.

 

[watercrawl]

Thanks Nathan, I will give the first three a shot and order an aluminum bit when I order from Enco again.

 

[Carl_First_Timer]

I was going to say climb mill and aluminum cutters but Nathan went farther than that and gave some solid advice. Good luck.

 

[Salem Straub]

Good advice there. I'll add that I've found lathe turning the tenon for these works well. I turn the tenon on the handle though, and plunge mill a 3/4" round mortise into the bolster. I just keep check-fitting the handle end as I turn the tenon down, to get a press fit into the bolster.

 

[watercrawl]

Neat idea Salem.

But for this handle, with the ferrule being two pieces, I wanted the tenon on the ferrule to fit within the body to help hold the two pieces together.

 

[Salem Straub]

Yep, I can dig that. Just wanted to relate something for you to try out if you like. In my case, I often make the handle in two pieces, and the ferrule will hold them together in front. (Not with a lathe turned handle though, more for a mortised handle.)

 

[watercrawl]

Always appreciate another perspective/method/etc. Thanks!!

The absolute most difficult thing for me is making the opening in the front of the ferrule match the tang exactly. I always end up too wide, too fat, not even, not parallel, not etc.

I figured this method could give me tighter tolerances.

I have you, Salem, to thank for the idea. I read a WIP thread where you milled the tang slot in the handle. Measured the thickness of the tang, divided in half, traced the tang, and milled it out.

Probably nothing new, but the way you presented it helped a lot. I've since made a few handles that way....I really like the method. So thanks again!!