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SpikeC
02-29-2012, 03:41 PM
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.

Chifunda
02-29-2012, 03:59 PM
I can't speak from experience, but perhaps a 1/4" brad point bit?

lowercasebill
02-29-2012, 04:18 PM
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

Pabloz
02-29-2012, 04:49 PM
Spike,
I would go 1/8" round 1, 3/16" round 2 then finish w1/4" round 3.

PZ

SpikeC
02-29-2012, 05:11 PM
Thanks Pablo, what do you think of using carbide?
The problem with dental tools is that they lack sufficient length to do the job.

Rottman
02-29-2012, 05:15 PM
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....

Pabloz
02-29-2012, 05:22 PM
Solid carbide is the best way to go IMHO. LIGHT Soapy water as coolant....spray bottle set to stream.

kalaeb
02-29-2012, 07:31 PM
What RPM's are you guys using to drill horn, ivory etc...?

apicius9
02-29-2012, 07:53 PM
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

SpikeC
02-29-2012, 09:18 PM
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.

Chifunda
02-29-2012, 09:55 PM
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?

SpikeC
02-29-2012, 10:31 PM
Good suggestion, thanks!

Bill Burke
03-02-2012, 12:12 AM
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.

Chifunda
03-02-2012, 09:49 AM
BYW, this is hippo ivory.

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

http://i1153.photobucket.com/albums/p508/Chifunda/NaughtyHippoDeceased.jpg

bikehunter
03-02-2012, 04:21 PM
Have you checked with your dentist Spike? <g>

HHH Knives
03-02-2012, 05:13 PM
I just finished a knife with Hippo ivory. Feel free to call or PM I would be happy to give you the drill info. :)

Taz575
03-02-2012, 05:16 PM
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!

SpikeC
03-02-2012, 08:07 PM
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!

sachem allison
03-02-2012, 08:13 PM
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.

SpikeC
03-02-2012, 08:18 PM
Rotozip!! Why didn't I think of that? It would be way fast for going sideways than a needle file. Thanks, Son!

sachem allison
03-02-2012, 08:19 PM
that's what I'm here for. haha!

Bill Burke
03-02-2012, 08:20 PM
Find John Perry MS and order both sizes of his handle broaches. You will be glad you did.

apicius9
03-02-2012, 08:25 PM
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

SpikeC
03-02-2012, 10:32 PM
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!

apicius9
03-02-2012, 11:06 PM
.... 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

Bill Burke
03-03-2012, 12:45 AM
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.



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!

SpikeC
03-03-2012, 05:42 PM
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!