# Working with ivory



## SpikeC (Feb 29, 2012)

I am just starting to drill into a piece of ivory and I was wondering if anyone had any suggestions on the best type of drill bit to use for this. I'm drilling a pair of 1/4 inch holes for the tang of a knife several inches deep. I normally start these with a 1/4 inch forstner bit, butt this seems to be reluctant to go and is generating a bit of heat.


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## Chifunda (Feb 29, 2012)

I can't speak from experience, but perhaps a 1/4" brad point bit?


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## lowercasebill (Feb 29, 2012)

you are drilling tooth not wood .. dental burrs are carbide or diamond and always used with water coolant.. there are dental type burrs for dremal tools


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## Pabloz (Feb 29, 2012)

Spike,
I would go 1/8" round 1, 3/16" round 2 then finish w1/4" round 3.

PZ


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## SpikeC (Feb 29, 2012)

Thanks Pablo, what do you think of using carbide?
The problem with dental tools is that they lack sufficient length to do the job.


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## Rottman (Feb 29, 2012)

lowercasebill said:


> you are drilling tooth not wood .. dental burrs are carbide or diamond and always used with water coolant.. there are dental type burrs for dremal tools



I have plenty of old school dental drills, rose burrs etc. with an old dentist's machine, none of them are carbide or diamond....


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## Pabloz (Feb 29, 2012)

Solid carbide is the best way to go IMHO. LIGHT Soapy water as coolant....spray bottle set to stream.


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## kalaeb (Feb 29, 2012)

What RPM's are you guys using to drill horn, ivory etc...?


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## apicius9 (Feb 29, 2012)

kalaeb said:


> What RPM's are you guys using to drill horn, ivory etc...?



I have no idea what the recommendation by an ivory pro would be, but I have drilled with around 1000 rpms with no issues. I have also drilled interior mammoth ivory with a normal brad bit before and not had any issues. Just going slow and avoiding heat to build up. I always stuck to Mark's short tips here: http://markknappcustomknives.com/wersindwir.php , i.e. I also avoid water. I have one piece as a ferrule that has developed a network of little cracks on the front side, and that was an early one of which I know I heated it up way too high and dipped it in water to cool it down, so those two are definitely not recommended. 

Mammoth tooth is a different thing altogether, Mario may be our resident expert on that one. I drilled through thinner pieces with a masonry drill and that went o.k., but I always glue the pieces between something because the material is so brittle. I have avoided drilling ferrule pieces so far, but it is on the list...

Stefan


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## SpikeC (Feb 29, 2012)

I understand how water could cause problems with material that has been over heated, but what about using it as a prophylactic? That is, to prevent heat build up in the first place?
BYW, this is hippo ivory.


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## Chifunda (Feb 29, 2012)

I use mineral oil to prevent drying out and cracking of elephant ivory pistol grips. Perhaps it might work as a coolant/lubricant when drilling?


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## SpikeC (Feb 29, 2012)

Good suggestion, thanks!


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## Bill Burke (Mar 1, 2012)

just use a cobalt drill no need for carbide but you want one for drilling metal not wood. keep the rpms about a thousand or so and avoid building up too much heat. go slow so as to avoid needing any kind of coolant. 1/4 inch seems like a large hole for a tang slot. pm me if you want.


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## Chifunda (Mar 2, 2012)

SpikeC said:


> BYW, this is hippo ivory.



If I had known you wanted hippo ivory, I could have gotten you a deal.


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## bikehunter (Mar 2, 2012)

Have you checked with your dentist Spike? <g>


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## HHH Knives (Mar 2, 2012)

I just finished a knife with Hippo ivory. Feel free to call or PM I would be happy to give you the drill info.


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## Taz575 (Mar 2, 2012)

I've looked at some ivory, but I'm kinda scared working with it. I ruin enough cheaper materials easily!! I'll stick to giraffe and camel bone for now I think! I am familiar with that and used to how it works. I have enough stuff that's a bear to work as it is.

Plus I'm a little heavy handed; I set my work bench on fire a few times while hogging out blade profiles years ago!


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## SpikeC (Mar 2, 2012)

Thanks for tip, Bill, the cobalt drill bit worked a charm. The reason that I use 1/4 inch for tang holes is that I have had trouble with bits wandering in endgrain. I used a 3/16 bit with the ivory and once again it drifted, so now I'm filing away with a 00 F. Dick needle file. It is a little slow going!


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## sachem allison (Mar 2, 2012)

That is why I sent 2, just in case you needed a back up. I usually use my dremel and some burrs to drill ivory, if I have to go deep I use cobalt or those rotozip type drill bits( the ones for ceramic tile. they usually work well.


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## SpikeC (Mar 2, 2012)

Rotozip!! Why didn't I think of that? It would be way fast for going sideways than a needle file. Thanks, Son!


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## sachem allison (Mar 2, 2012)

that's what I'm here for. haha!


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## Bill Burke (Mar 2, 2012)

Find John Perry MS and order both sizes of his handle broaches. You will be glad you did.


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## apicius9 (Mar 2, 2012)

For sideways cutting you can also use Foredom cutting drills, they come in thinner than 1/8" but you will need the matching collets for them and they don't go very deep: http://www.foredom.net/drills.aspx I use them to clean out the ferrule slots a little bit before I switch to files. Just be careful with the heat again - at 15,000 RPM the material heats up quite fast...

Stefan


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## SpikeC (Mar 2, 2012)

Bill, I can make broaches and such, I have done so many times over the years in making jewelry. I just haven't gotten around to it yet! I've seen John Perry's and will use them for inspiration. 
Stefan, the area near the opening is not the problem, I have that covered, it's the 1 1/2 to 2 inches at the bottom of the hole that are the issue! The 00 files that I'm using work but are just a bit slow, so I will make a broach out of some of the plentiful scrap pile of O1 that I have in stock!
I really appreciate all of the helpful suggestions and tips from everyone, and I am making progress!


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## apicius9 (Mar 2, 2012)

SpikeC said:


> .... so I will make a broach out of some of the plentiful scrap pile of O1 that I have in stock!



So, how much will you sell the extras for  I could use some...

Stefan


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## Bill Burke (Mar 2, 2012)

I dont know if you have a surface grinder or not but a broach can be made very easily from an old file with one, as long as you have a stone for it.




SpikeC said:


> Bill, I can make broaches and such, I have done so many times over the years in making jewelry. I just haven't gotten around to it yet! I've seen John Perry's and will use them for inspiration.
> Stefan, the area near the opening is not the problem, I have that covered, it's the 1 1/2 to 2 inches at the bottom of the hole that are the issue! The 00 files that I'm using work but are just a bit slow, so I will make a broach out of some of the plentiful scrap pile of O1 that I have in stock!
> I really appreciate all of the helpful suggestions and tips from everyone, and I am making progress!


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## SpikeC (Mar 3, 2012)

I've made similar tools for working with hard carving wax. I use a small cutoff wheel with diamond surface in a flex shaft machine and just cut whatever teeth I need. I finished the hole for the tang today with some coarse cut wax files now it's on to the final shaping of the handle!


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