Advice drilling fossil Walrus tusk

[Robert Erickson]

I going to use some fossil Walrus tusk for bolsters and would like advice before drilling holes for pins. I'm going to use 2 pins but they're not going to be in the center of the material. They'll be off center and I'm concerned about the drill bit wandering because that area is curved.

What type of bit would be best? Solid Carbide? Cobalt? What speed?

Normally I place the blade over the material I'm drilling to use it as a template but since it's curved that would be difficult. Suggestions?
Thanks!

 

[Zemapeli]

Have you considered using a milling vice to hold the material? Or perhaps you could buy a couple clamps with rubber or 'grippy' contact areas??

 

[Zemapeli]

I don't know that speed should be much of a problem as long as the drill bit bearings are sound and the drill is plumb and true. Make sure that the material is properly secured firstly. Speed of the drill bit itself wont be your problem. In fact, high speed with ivory is a good thing as long as it does not heat up the ivory and cause a stress crack. Drilling should not cause heat cracks unless the diameter is large enough to allow the contact of the two materials to cause friction. Speed is a good thing for a clean and precise hole especially when drilling into a surface that is not level.

Your problem will be figuring out a way to secure the ivory to the press table. I would go with some clamps that have a rubber grip surface and secure the ivory very well.
Then your next problem will be with how fast you press the drill through the medium (ivory).... (not with your drill speed itself; rpm/rotation etc.)
So, drill with medium to high speed, but drill down very very very very slow.
-Zemapeli

 

[Stacy E. Apelt - Bladesmith]

Use a drill press.

Glue or clamp everything down sturdy. A few drops of CA on a scrap piece of hardwood/Micarta makes a great drilling jig to clamp on the drill press table.

Have a firm backing board. Any hardwood or Micarta will work. If not, it will chip badly as the drill exits the back of the hole.

Use SHARP bits.

Drill slow and with moderate pressure. Speed makes heat ... pressure make heat ... avoid heat!

Keep things cool ( see above). Don't let the bit or the ivory get hot. Peck gently at the hole if needed, or lube with a squirt of water.

Plan your holes well ... there are no re-takes!

Allow a bit of extra thickness in your slabs for sanding down the bolsters and removing any chipping at the hole edge. I would drill the holes, then sand the bolsters to final shape with temporary pins holding them together.

 

[Lieblad]

I normally hot glue odd shape workpieces to wooden scraps so they can be viseclamped or held to a fence on the tablesaw.

The word "fossil" has me puzzled. Does that mean fossilised to stone (thousands of years) ? Or does it mean its just old enough to be pardoned from environmental or species restrictions ?

 

[Robert Erickson]

Use a drill press.

Glue or clamp everything down sturdy. A few drops of CA on a scrap piece of hardwood/Micarta makes a great drilling jig to clamp on the drill press table.

Have a firm backing board. Any hardwood or Micarta will work. If not, it will chip badly as the drill exits the back of the hole.

Use SHARP bits.

Drill slow and with moderate pressure. Speed makes heat ... pressure make heat ... avoid heat!

Keep things cool ( see above). Don't let the bit or the ivory get hot. Peck gently at the hole if needed, or lube with a squirt of water.

Plan your holes well ... there are no re-takes!

Allow a bit of extra thickness in your slabs for sanding down the bolsters and removing any chipping at the hole edge. I would drill the holes, then sand the bolsters to final shape with temporary pins holding them together.

Thanks!

I normally hot glue odd shape workpieces to wooden scraps so they can be viseclamped.

The word "fossil" has me puzzled. Does that mean fossilised to stone (thousands of years) ? Or does it mean its just old enough to be pardoned from enviromental or species restrictions ?

Thanks!
I received the material from the customer so I'm not sure.

 

[Bill DeShivs]

If you can easily file the ivory, it's not fossilized.

 

[Stacy E. Apelt - Bladesmith]

Fossil means different things in differed instances. It refers to both age and mineralization. Fossil walrus and fossil ivory from mammoths is somewhat mineralized, but not completely replaced with minerals, as is the case with million year of dinosaur and plant fossils. Fossil walrus is usually between 200 and 1500 years old.

The word actually has nothing to do with being turned to stone.The term is Latin for ""dug up".

Many folks call me an old fossil.

 

[Robert Erickson]

Thanks for the advice. It worked well to CA glue it to a piece of micarta longer than the walrus tusk then place another piece of micarta just thicker than the walrus tusk behind it to lay the blade on to serve as the template. I don't know if I described it well. I should have taken pics of the process. It wasn't as bad I was expecting. Here are some post drilling pics.

 

[jdm61]

Many folks call me an old fossil.

But we REALLY don't want to hear about how is trying to drill you. But seriously, the couple of times that I have used "old" walrus in a hidden tang configuration , I was pleasantly surprised at how easy it was to work.

 

[LARRYZ10]

I would like to suggest that if you have this problem of your drill wandering on curved material you might want to try a "center drill". I like the 1/8th inch shanked one that is sold by Jantz knife supply for less than $5. They have a drill point on each end of the drill and are designed to provide a starter hole for your drill like a center punch except they rotate. Also many knife makers have made a devise to hold a blade level while they drill holes through a tapered tang. It can also hold your knife in a supported position while you drill through curved material like antler. Here is a photo of my aluminum clamp that uses a " 123 block". The photo doesn't show it but I made a wooden wedge to go under the scales at the dangling end. I copied this jig from David Sharp I think. Larry

 

[Robert Erickson]

That's a great drilling jig Larry. I'm going to have to make one of those. Is the 123 block secured to the bottom aluminum plate?

 

[stezann]

Larry posted a very good jig. But for just drilling into a bolster there is an easy way.
I know you already drilled, but for the future if you need to drill on curved surfaces, and you only have a drill press, consider doing it upside down.
That's what i always do for drilling folders, both scales and bolsters, regardless their materials, when they are not true and parallel...since i need to flatten one side, i drill from that reference. It will prevent the drillbit to wander.
A simple version of the jig it's a square pipe section with a slot on top....you just have to clamp the piece inside, upside down under the slot, and to take it to the drill press.....

 

[Robert Erickson]

Larry posted a very good jig. But for just drilling into a bolster there is an easy way.
I know you already drilled, but for the future if you need to drill on curved surfaces, and you only have a drill press, consider doing it upside down.
That's what i always do for drilling folders, both scales and bolsters, regardless their materials, when they are not true and parallel...since i need to flatten one side, i drill from that reference. It will prevent the drillbit to wander.
A simple version of the jig it's a square pipe section with a slot on top....you just have to clamp the piece inside, upside down under the slot, and to take it to the drill press.....

Another slick idea, thanks!

 

[Natlek]

Use a drill press.

Glue or clamp everything down sturdy. A few drops of CA on a scrap piece of hardwood/Micarta makes a great drilling jig to clamp on the drill press table.

Have a firm backing board. Any hardwood or Micarta will work. If not, it will chip badly as the drill exits the back of the hole.

Use SHARP bits.

Drill slow and with moderate pressure. Speed makes heat ... pressure make heat ... avoid heat!

Keep things cool ( see above). Don't let the bit or the ivory get hot. Peck gently at the hole if needed, or lube with a squirt of water.

Plan your holes well ... there are no re-takes!

Allow a bit of extra thickness in your slabs for sanding down the bolsters and removing any chipping at the hole edge. I would drill the holes, then sand the bolsters to final shape with temporary pins holding them together.

I'm not a master, but I keep on the side several new drill that I use exclusively for for wood, G10 , Micarta ............no metal drill with them .

 

[LARRYZ10]

That's a great drilling jig Larry. I'm going to have to make one of those. Is the 123 block secured to the bottom aluminum plate?

No, It is not secured to the bottom plate. I drilled four holes through the "123" block into the aluminum base plate and tapped them for the stainless steel socket head cap screws. I forgot the exact size of drill and tap but I think the bolts are 1/4 inch. The top piece of aluminum just has four clearance holes. It was easy to make. The materials were from the local metals dealer in the scrap bin so it was cheap as well. I use this for all tapered tang knives but it works for rounded antler and bone as well. Larry