Thread: Help drilling into end grain with forstner bits

What speed are you drilling at?

Originally Posted by rwbuild

What speed are you drilling at?

As slow as I can, which is 600rpm I think.

Hi Monty, are you using HSS ones or carbide ?
I bought quite a few cheap ones off Ebay with carbide tips and they work well, although don't do a lot of end-grain cutting.
You would need to Cut on slow speed with a lot of pressure applied by the drill press.

You may also need to cut a very small diameter pilot hole as the centre spur point maybe struggling through the end grain, make sure it is smaller than the diameter ot the spur or you will have problems centering the bit in the hole.

Hi Monty
The holes you have drilled already don't look too bad by the look of your photo.
Drilling into endgrain is always a hassle to some extent. And with 41mm bits you have done well to get those holes as you have!.
By the look of what you are making...rustic candle holders, I would not worry too much if the holes are not perect....hey, they have a rustic bark edged surround, no buyer is going to be looking for a "press fit" candle holder.
Might be a good idea to leave the metal bit of the candle holder sticking up a bit from the timber at least.
Timber and candles are a really dangerous mix, and can burn houses down..even kill people.

Will they work in other timber?
Possibly your branches have seasoned and are now rock hard
Just an idea.
H.

600 RPM is too fast, I'd be looking at something like 250 rpm for a 41mm bit.

My first question would be how have you been sharpening the bits

Originally Posted by artful bodger

Might be a good idea to leave the metal bit of the candle holder sticking up a bit from the timber at least.
Timber and candles are a really dangerous mix, and can burn houses down..even kill people.

Even better would be to add a glass insert like this.
There are a wide assortment of these inserts available at IKEA at silly prices.


One way I have found to improve the rate of drilling is to drill a small pilot hole ~2/3rds the diameter of the centring tip of the Forstner bit.

Originally Posted by BobL

600 RPM is too fast, I'd be looking at something like 250 rpm for a 41mm bit.

My first question would be how have you been sharpening the bits


Even better would be to add a glass insert like this.
There are a wide assortment of these inserts available at IKEA at silly prices.


One way I have found to improve the rate of drilling is to drill a small pilot hole ~2/3rds the diameter of the centring tip of the Forstner bit.

Yep, that sounds like a good idea.
We don't have Ikea here.
Nice to know that no one might get burnt tho.

Originally Posted by mark david

Hi Monty, are you using HSS ones or carbide ?
I bought quite a few cheap ones off Ebay with carbide tips and they work well, although don't do a lot of end-grain cutting.
You would need to Cut on slow speed with a lot of pressure applied by the drill press.

You may also need to cut a very small diameter pilot hole as the centre spur point maybe struggling through the end grain, make sure it is smaller than the diameter ot the spur or you will have problems centering the bit in the hole.

Just carbide bits, no HSS.

Thanks, will give the pilot hole a go. Also i find as soon i put any kind of substantial pressure with the drill press the bit bits and drill stalls. This is very likely just because it's a cheapo drill press with no power but the only way i've managed to get through the ones i have was with very light pressure and slowly chipping away at them.

The first few took about 5 minutes, which was fine, but the last one i did was more like 20+ minutes and now just can't get anywhere.

Originally Posted by clear out

Will they work in other timber?
Possibly your branches have seasoned and are now rock hard
Just an idea.
H.

Actually, that could be the case. I've been drilling these over a number of weeks and the first few I did would be over a month ago. The branches have been sitting my garage for a while now.

I suppose I could try and harvest some more of the tree at my parents place and try and cut them up straight away.

I thought it was best to let the wood dry out first though before cutting into to avoid splitting?

Originally Posted by Monty85

Just carbide bits, no HSS..

How are you sharpening the carbide?

Thanks, will give the pilot hole a go. Also i find as soon i put any kind of substantial pressure with the drill press the bit bits and drill stalls. This is very likely just because it's a cheapo drill press with no power but the only way i've managed to get through the ones i have was with very light pressure and slowly chipping away at them. .

. . . . that explains it all. You've taken the edge off by chipping away at the wood at high speed. The carbide doesn't have that good an edge to start with and even though its harder than HSS it will still eventually dull. Combine that with the wood drying out.

You do need a powerful drill (1HP) and it has to be dome at low speed. When I drill the 52 mm size I use 160 RPM.
Holding the bankia pods without destroying the exterior is tricky. I use those sticky woven look rubber mats that are also good for taking lids off. I warp the pods in the mat and put them into the drill vice - it works most of the time.

I recommend using HSS bits for end grain. You will have to sharpen often, I just use a diamond file or slipstone and hone the edge a bit while it is still n the drill press. Hss will give a sharper edge than carbide and will withstand heat longer. Carbide is good when it is sharp, but heat destroys the edge very quickly. Everytime u get stuck and it burns, u generate alot of heat on the cutting edge, trying to push harder to get through just makes it worse. If u look closely u can probably see light shining on the cutting edge, because u have rounded the edge away.

If you are going to do a lot of them go for a TC bit, not just HSS, they cost more but will be worth it. Also, don't use a pilot hole for forstner bits, they will wonder and cause you no end of problems in those blanks.

Originally Posted by dai sensei

If you are going to do a lot of them go for a TC bit, not just HSS, they cost more but will be worth it. Also, don't use a pilot hole for forstner bits, they will wonder and cause you no end of problems in those blanks.

I Haven't had any problem with bits wandering when using a pilot hole - if anything its the other way around.

Originally Posted by Monty85

Attached a picture of what im trying to achieve.

WP_20150224_005.jpg

Does anyone have any tips on a way to make these holes. They don't need to perfect, they just need to look clean from the top and have a flat bottom so the candles sit right.

Monty

perhaps using a router and template is the way to go about it