Blowouts Drilling ivory, bone, antler etc..

backtines

backtines

Well-Known Member
Hey guys , just wondering how you guys drill your, stag, ivory, bone , etc .. Scales ?

When I drill this stuff, I always put a piece do tape on the bottome of my scales to prevent "blowouts, or chips ". But I sometimes get a clean hole and more then less , I don't.. I'm always having to grind down deeper then I want to , to clean up the blowout .. It sucks when I drill through a piece of antler and I have a blow out in the deep part of the groove. I then need to grind all the good stuff away just to get rid ofthe blow out .

Can you guys tell me what I'm doing wrong ? Can you tell me the way you drill through this stuff?

I haves ice piece of mammoth ivory , that I've had for a few years and am a little afraid to drill it because of this..

Or do I look at this in a completely different way and accept the blow outs and clean them up later.. ( which is what I've been doing all along )

Your thoughts ?
 
Use a small pilot hole. 1/8 or less, then a size or two larger, then the actual size. Works for me. Use SHARP bits and go SLOW.
Im sure there is a better way Mikey cause we are in the same boat!

God Bless
Mike
 
I invested in a counterbore in several sizes and start a centered pilot hole using a "from underneath" square tube with a slot jig that lets me clamp the tang up underneath with any taper accounted for with a shim. Once I've got my pilot, typically 1/8" through drilled then I can come back with my 3/16 or 1/4" bit from the face for the shank, then also from the face drill any step for Corby fasteners. For materials with character I also use a layer of blue paper tape pressed well into any low areas. If it's any material that's unique I use a brand new bit and a quite fast bit speed with very slow advance through the material with many passes taken to clear chips as I go. The slower speeds seem to "grab" more.

If I'm using 1/8" pins, which I often do with ivory, I just hope for the best, the fast rotational speed, slow advance and much chip clearing has worked well enough I don't recall an issue with them.
 
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What Mike said. I drill a small pilot hole and then drill to size from the face side. If it blows out a little on the back side its no big deal.
 
Try gluing a piece of fiber liner material on the face side. Then all you have to do is grind away the liner after drilling.
 
Thanks guys for fast response. . I should pop up some pics of my ficture but im laying on couch right now. Lol

Anyway .. I built a fixture . I took a piece of 3" channel about 4" in length. I milled a slot about a half inch wide throughout the center of it leaving 1/2" not milled in front and an inch or so on back end.. I then clamp one scale to tang , I then clamp the clean side of tang to the bottom face of my fixture. This gives the a parallel flat to drill my hole through. I don't try to rest the face of the scale on the vice anymore or try to shim it level. The channel fixture is flat , level and parallel , so I just clamp the blade to bottom if it.. Works great.. I then use the undersized bit for the proper ream. I don't know the number of the bit right now , but when using 1/8 pin I drill undersized then I ream to 1/8" .. I use tape on face of scale and I tried going slow and spun my mill at a faster speed too.. I'm also moving bit ever so slow , constantly cleaning chips from hole.. When I get to where the bit comes through the scale is when I get a little nervous.. I pop through , then send reamer through. I take a peak , pull the tape off and sometimes it's perfect and sometimes it leaves a friggin pothole .030 or more sometimes. Then I have to start grinding away the good stuff..
 
Steven Long said:
Try gluing a piece of fiber liner material on the face side. Then all you have to do is grind away the liner after drilling.
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That sounds good but what if the hole is gonna line up in the grooves of the antler? That's where I have most of my potholes..

I even take a piece of the blue tape and push it into the nooks and crannies hoping that would work. .. Like I said , sometimes good and sometimes not good.
 
backtines said:
That sounds good but what if the hole is gonna line up in the grooves of the antler? That's where I have most of my potholes..

I even take a piece of the blue tape and push it into the nooks and crannies hoping that would work. .. Like I said , sometimes good and sometimes not good.
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Sorry about that, I was referring to using the mammoth. I used a thin piece of plastic on the only two I have done but didn't think about how it would melt on the grinder. It was a nasty mess. Then I saw someone who recommended to use the fiber liner. I think it was Charles Turnage.

As far as the stag and textured material, I will be watching this thread for some pointers. I have a few in the works also.
 
Mike,
Try an end mill.
Drill through under size.....flip over the scale and use the chucked drill bit to allign the hole.....clamp.....finish hole with proper size end mill.

Rudy
 
What can help on this even though the blowout - and that's the right word for sure - still happens is to leave the top surface of the scale oversize until the holes are completed. It's far less a chance for the hole to be bad down from the surface just a bit. Now when you shape the scale top the holes will be good. Frank
 
Frank Niro said:
What can help on this even though the blowout - and that's the right word for sure - still happens is to leave the top surface of the scale oversize until the holes are completed. It's far less a chance for the hole to be bad down from the surface just a bit. Now when you shape the scale top the holes will be good. Frank
Click to expand...

Thank you to everyone for your thoughts on this matter .. Im sure glad Im not the only one dealing with this ..
I get everything that you all are saying and prety much tried alot of these ideas .. But there still is those antler blowout and chips in the nooks and cranies that sometimes pop up.

Ya know as Im writing this I just had an idea to maybe coat the drilling area with rubber cement , or a rubbery glue ? Something that will hold the pores on the surface together .. Id imagine it would be easy for clean up too ..

I think Im gonna give that a try too on a piece or two of scrap ..
 
My first suspects to repeated blowouts would be dull bits and running to slow of an RPM for the material.

That said... Now your part of the BLOWOUT club ! Welcome aboard :D I'll send your decoder ring ASAP

-Josh
 
Hey Josh, I certainly deserve one of those rings. If you want to find out just how bad they can get work the mammoth tooth material. Frank
 
+1 again on the speed. When I'm drilling mammoth ivory I run my small 5 speed drill press WIDE OPEN, with very very tiny advancements coming all the way back out with each pass, cleaning the bit if necessary, also making sure the epoxy is completely dry so there's no gummy build up.
 
Didnt get a chance to play last night . I took my kid out after work to knock on some doors and shovel walkways and driveways so he can make a few bucks. But yes , im feeling that one of the most talked about tips in this thread is the speed.. I will turn the mill up and ill start off with an even smaller bit, cleaning chips constantly and see how it goes from there..

Josh , Ill be waiting for my blowout ring .. lol.. ( Hey man, i went on Nora's facebook page and checked out the house , looking good bro , congradts !! Now send me my ring LOL !)
 
After the first few blowouts on my early knives, I adopted the "drill a smaller pilot hole from the bottom, and drill-to-size from the top" method. I'd buy cheapest import bits I could find in the common sizes that I always used for antler, bone, and stag. The reason behind this is simply to have a sharp bit to use with every knife handle, then toss them. Its cheap insurance against blowouts. I usually do not sharpen bits above 1/4", but I always save the USA-made ones anyway, vowing someday I will buy a Darex and never have to buy another bit ever. Incidentally, I use the same technique - more or less - for MOP.
 
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