Mother-of-Pearl: AARRRRRGGHH!!!!!

Frustration has arrived (a regular occurrence) at the Johnson shop!

Have any of you ever used up three sets of Mother-of-pearl in the attempt to get two knives handled with this material?!! Well, I did just this past week! (Oh, what the heck, they only cost me $51 for one piece and $69 for the other!!! Sheeeesshhh!)

One scale of both of the sets had, hidden, major cracks inside which necessitated the replacement of both from another set in order to finish the knives. Luckily, I'd just received a bunch of large slabs from my supplier and could match them up, or I?d be looking feverishly for more material. Now, as mentioned, these were both very large handles, and maybe that?s the problem. I don?t seem to have as much trouble with bad cracks in the smaller sizes. At leaset, if they are flawed, you can see the checks, as a rule.

Also, when drilling MOP, one would be wise to follow Ron Lake?s advice, given many years ago. He suggested using either carbide drills, or carbide end mills for drilling MOP. Of course if you're going to drill with an end mill, you need to drill a pilot hole to allow the center of the cutter to pass through the pearl, otherwise, it will not "drill" through the material. Perhaps a "center cutting" end mill would "drill" ok?

If you use screws to attach pearl handle pieces, be sure to use a very sharp, or new, counterbore. If it isn't sharp, it will not "cut" the edges of the hole, but will cause a little halo of "crushed" pearl around the edge of the hole. This little halo is not "cool," so do all you can to avoid it. I even bathe the counterbore with kerosene or paint thinner, using a solder brush, while I drill and this helps a lot. This also includes not getting the screw head too hot while sawing or grinding it off, as you finish the handle. MOP will probably take more heat than ivory, stag or other materials, but you need to watch that heat!

You made me laugh, Steve. I can sure relate to pearl troubles. I use cobalt drills and mineral sprits, and throw the bit away after drilling holes for one set of scales, but I still have to be especially careful when the drill breaks through the pearl to keep from getting that inverted cone-shaped fracture around the hole.

Don, above, reminded me that it's always a problem getting that drill through the other side of the pearl without it breaking out the "cone" on the other side.

One way that this can be remedied is by backing up the pearl with a piece of steel, Micarta or hardwood. You need to have it clamped pretty tight against the pearl, and stabilized, so that things are pretty solid. This will slow down the drill and keep it from "popping" through and chipping the material. I have tried covering the off-side with a glob of super glue and that helps some, too.

Once again, as Don mentions, a SHARP drill is probably the most important thing, so that it cuts the pearl cleanly, rather than crushing it (That's why I like carbide). As he notes, a coolant definately helps in getting a cleaner cut and managing the heat build up.

And, as he notes, don't be afraid to use tools. If a new drill cuts well, a used one cuts less well. One of my problems is my being too cheap to replace a cutter, or drill or counterbore before it gets so dull that it causes problems. A new belt is cheaper than ruining a $20-100 piece of handle material because it gets too hot and warps, or cracks, etc. Not to mention the lost time in re-doing what you messed up. Of course, I'm the only one that would ever do anything like that!!

Another area of concern: When grinding the MOP down to the tang, it helps to grind from the tang out, on both sides, so that the tendency to fracture against the tang is eliminated. Or even use a finer belt, 120X or 220X to lessen the tendency of the pearl to break-off in tiny checks as you grind the edges of the handle material down to the tang. It'll take longer, but eliminating those little fractures next to the tang, or spacer material, will be worth it. Maybe try a slack belt.

I also, when initially starting this process, will grind with a rough belt at first, on an angle, from the outside of the pearl to about mid point on the edge, then turn the handle over and grind from the inside out, lessening the tendency of the stuff to "chip away" as you grind that edge. This is like starting a grinding bevel on a blade, leaving a high spot down the center of the edge of the pearl. As you are grinding into, or toward the center, of the slabs, it won't chip the edges. Hope this makes a little sense.

Another technique that assists with pearl is to purchase a fine-toothed band saw blade, about 26-28 teeth-per-inch. Then the MOP isn't as prone to chip, or shatter, as with a rougher, say 10-14 blade, that is used to saw out knife blanks. It saws much nicer with the finer tooth blades. This requires changing the blade just for cutting one set of pearl, but it'll save you a piece of pearl now and then, so it's worth the effort.

Steve, it does make sense. Thanks for the tips!

Hey Steve, what you said makes me wonder if we ain't shirt tail cousin's I mean wore out drill bits, counterbore, dull belts. Heck, and I was thinking all this time I was the only one who worked my tools until thay just want go no more. You ought to see my scrap pile. I don't throw much away either, one of these days I'm gonna need it for something. It ain't wore out until its wore out, and just maybe I'll find something else to use it for. :

We both sound a little "Scotch," as my Dad used to say. Prob'ly are related not far back.

But I know better than to try to do a job with a tool that's going to do nothing but create heat, it's just that I get in a hurry and don't bother to get the right, sharp, bit, belt, etc,.....and usually pay the price.

Heck, a pile of used anything has to be worth something, someday, doesn't it?

Oh, I got a digital shot of one of the above-mentioned MOP-handled knives that I'll post here in a day or so. It's a Loveless-style Dropped Hunter with SS fittings. Not exactly your typical "working knife," but it's sure pretty, if you ask me. Any self respecting Mule Deer would be honored to be skun by this baby, though that's not very likely, one must admit! Note: "Skun" is spelled correctly.

Scun...I just couldn't find that in my Websters Must be a Manti word

Oh, I'm sorry! I must've misspelled that word. It shoul've been "skun."

I changed it....

No I didn't....

I'll probably send that photo to you for posting, Bob, if you'd be so kind. It'd probably end up looking like Abalone by the time I got through running it through this MAC!

Here is the culprit...

Magnificent.

Pearl can be a pain. I undersize drill the holes, hen use a 4 flute carbide reamer at med - high RPM to keep from flaking out the back of the hole.
I also tape the backside and press down against hardwood.
I usually tape both sides when I grind to shape. It helps keep from chipping on the edge. Also keep the pearl moving. Heat buildup is hard on pearl.
I tape it (bottom side) when I cut it with the bandsaw too.
Always cut into the pearl - never cut out of it - it breaks.
Be careful peening rivets too. One tap too many is all it takes. I would rather spin a dome head with the drill press or use screws.
It is pretty though.

hi all.....been very busy for the last two months, this is my first visit here since the crash of dec. I wanted to add that I found the best way to drill pearl without cracks is to start the hole with the proper size drill....go half way thru...then use a small one to go all the way thru.....turn it over and drill with original size.......the problem lies in the nature of the material itself......it grows in layers, and the stress upon any given layer can cause that line to seperate from the rest........tricky stuff......

Great tip, Tom! I'll use it, too.

Thnaks for the visit and thank you, too, Tom, for that good advice form the islands. I've tried that process before, drilling from both sides. I didn't really have a reason or theory behind it, other than to try to eliminate the punching out of the outer surface as the drill exits the pearl. Knowing about the layered growth process helps. Surely makes a lot of sense. I'll be trying it again.