Recommendation? Drilling African Blackwood - tips and tricks?

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Cushing H.

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Folks - I have been (for the first time) working with african blackwood as components of Wa handles. Part of the construction requires drilling holes (3/8") into the blackwood. this has proven tricky - the wood tends to (at least for me so far) grab the bit - making drilling the holes somewhat ..... interesting.

does anyone have any hints or tricks that you can pass on to me to make this experience more predictable?
 
Slow .....up and down...up and down little more ......up and down ...to clean drill bits . And use something hard under wood /I use aluminium / to avoid cracks when drill bits come out on other side ......
Properly sharpened and sharp drill bits is must , of course...:)
 
Try a forstner bit for drilling dowel holes, or just larger holes in general. I had a real "fun" time using a 3/8" twist bit trying to drill through a block of stabilized Indonesian ebony lol. You can also use some wax or oil for lubricant and then clean the hole out with mineral spirits or acetone if gluing or epoxying inside the hole.

If you don't have any or don't want to wait to get a forstner bit before finishing your handle you can also drill the hole to size in increments (e.g 1/8" to 1/4" to 5/16" to 3/8" etc).

~Paul
My Youtube Channel
... (Some older vids of some of the older knives I made)
 
I use either a Freud Precision Shear series Forstner bit or a Lee Valley HSS brad point twist drill (currently Lee Valley is offering free shipping with no minimum purchase). Both work extremely well (with the workpiece clamped in a vise). I don't like using normal 118˚ or 135˚ twist drills for precision holes in wood. I highly recommend purchasing the right tool for the job. It really is worth the few dollars.
 
If you only have twist drills and are a ways from getting forstner or brad point bits - you can try clamping a pre drill board on top of your blackwood (as well as under, as N Natlek suggested).

This is difficult to do properly - a few tips - • Drill before shaping so that you are drilling into flat materials. • The sacrifice board should be at least 3/8" thick and hard wood or plywood not simply a piece of pine. • The pieces need to be securely clamped together so to be as one otherwise any movement disrupts the intended purpose of the top piece.

All this is a real pain and best kept as an emergency procedure. Better off to have sharp "woodworking" bits.
 
African Blackwood can leave deposits in the drill flute. When the flutes get clogged the drill will not do it's job. Be sure the drill flutes stay clean. You may need to turn the drill off to clean the flutes.
 
Thanks folks.

natlek ... I was doing the slow up and down. When I said “grab”, i meant GRAB. Slight downward pressure in a cleaned out hole, and all of a sudden the wood is shifted In the clamp (yes, it/they were clamped).

sonds like Forster bits are a natural to try. I have to go out tomorrow to Home Depot (hose repairs :-(. ), can look for them there. If not, very nearby that are both harbor freight, and a Menards ... one way or another, i should be able to find them.

grrrr ... this sounds like an additional argument for that mini mill I keep thinking about.....
 
Cushing H. said:
Thanks folks.

natlek ... I was doing the slow up and down. When I said “grab”, i meant GRAB. Slight downward pressure in a cleaned out hole, and all of a sudden the wood is shifted In the clamp (yes, it/they were clamped).

sonds like Forster bits are a natural to try. I have to go out tomorrow to Home Depot (hose repairs :-(. ), can look for them there. If not, very nearby that are both harbor freight, and a Menards ... one way or another, i should be able to find them.

grrrr ... this sounds like an additional argument for that mini mill I keep thinking about.....
Click to expand...
It s drill bit ............take another one , this time good one .
 
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as far as the grabbing, maybe try rubbing a piece of bar soap on the outside of the drill bit before drilling into the wood.
 
Natlek said:
He driling /cutting undersized hole... tip don t cut like should and push thru wood rest of bit jammed because hole is undersized ..
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Natlek ... I think language is getting in the way a little ... but I think I understand what you are saying. In have sharpened this bit a number of times ...given what just said, i will go back and take a close look at the bit geometry...
 
Just for reference though ... it is ONLY. In the Blackwood this bit is having problems. The same bit has gone some 2 - 2.5” into stabilized spalted wood with no problems at all...
 
Cushing H. said:
Just for reference though ... it is ONLY. In the Blackwood this bit is having problems. The same bit has gone some 2 - 2.5” into stabilized spalted wood with no problems at all...
Click to expand...

Cushing H. my friend .......different material act different when you try to cut them.I have hundreds drill bits which need resharpening.Many of them will drill easy thru some material ...... listen to me , get new drill bit and your problem is solved .There was no magic .....
PS .How long is that drill bits ?
 
Blackwood and many other tropical woods in the rosewood family and other woods with an oily nature will cake up in the flutes and cause the bit to grab. They create fine dust more than drill chips and this mixes with the oils that come out as the bit creates heat. On ebony you can actually see beads of oil show up on the outer surface of the block.

This swarf mixture is gummy, sticky, and very dense. It will completely clog the flutes, creating an air tight hole and also sticking to the bit as well as the sides of the hole already drilled. As friction builds up it can stop a low powered drill press. It can also split or tear the block of wood down the sides and ruin it. In the worst cases. it can heat up to the point where the wood burns and literally blows the piece of wood apart by the steam/vapor pressure inside the hole. This can make quite a loud POP when it happens.

To drill these woods:
You need sharp bits!
Slower speed.
Lighter, but sufficient, pressure
Pump the drill bit in and all the way out every five seconds.
Clear the flutes if\\when needed. ( I rub a block of scrap wood along side the running bit to knock out the gummy swarf.
Use Forstner or brad point bits if you have them.
 
Mr.Wizard said:
Would this help?

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Mr Wizard ... given what others have indicated about accumulation of sticky stuff, I’m not sure if this mod will work here? Yet ... that is a really cool idea, and will need to keep it mind (and give it a try on dead soft copper sheet ... something I still struggle with a little...)
 
Thanks Stacy and all others ... lots to digest. These holes (in the Blackwood) are pretty shallow ... I will give the Forstner bits a try first, then try other options if that does not work
 
Update - I was able to obtain a forstner bit today and tried it on the last hole I needed to drill for the current handle.

Using it was like night and day versus a twist drill bit. Nice clean hole, not a sign at all of "grabbing" by the bit on the wood :-) .

Thank you all for the suggestion.
 
I bought a cheap set of forstner bits off of ebay years ago for $14...I think there are 10 bits in the set. Used them hundreds of times and they still work great. One of those times where you buy the cheap one and it works like a charm!
 
Randydb said:
I bought a cheap set of forstner bits off of ebay years ago for $14...I think there are 10 bits in the set. Used them hundreds of times and they still work great. One of those times where you buy the cheap one and it works like a charm!
Click to expand...
I looked at a couple sets ... but then got just the single bit. Like many people here (likely) Most holes I drill are 1/8” or smaller (and often one step oversize ) ... so I just would not need all those other sizes. May this one bit last me as long as yours have :-)
 
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