Thread: Help drilling into end grain with forstner bits

I've joined this interesting thread quite late, the responses are excellent.

Ive been asked to make quite a number of candle holders (wife's new hobby), flower pots and Christmas tree stands.

ALL of them require end grain drilling to considerable depth (80, 150 and ~100mm respectively) and the Forstners range from 35mm to 58mm.

The timbers are oak, gravillea branch sections (80mm wide) and well dried pine. I've done over 100.

The bits used are a Carb-I-tools kit from Total Tools. There are perhaps 20(?) to the kit. The price was extremely reasonable, but I couldn't say if they are CT or HSS.

Unlike the hapless dudes here, there seems to be a few tricks that I've used very successfully....

-- heat is the absolute enemy.
-- slowest drill possible. There is a sweet spot where too slow is just too slow, but at some magic speed it's just glorious. Any faster and you just get squeal and heat. I've found going too slow just increases heat (do the right chip sizes remove heat in the same principle as on a metal lathe?)...then...
-- I start with the slowest speed and REASONABLE pressure and look to get 5mm slivers out. If they are longer, I increase the speed 1 notch and if shorter I add more pressure. There is a goldilocks and watching the chip size is key.
-- mount the big 100mm dusty hose overlapping the hole, with the lip on the shaft of the bit and EVACUATE those chips the instant they form. Suck it all out. Retained chips and dust = heat.
-- drill the first part of the hole perfectly. Take time and do it slowly. As others have said, the edges guide the bit and if it's wonky to start, the friction is crazy a short way in.
-- I'm contrary to the wisdom of earlier posts. I've found holding the work in my left hand lets me gauge very effectively the balance of pressure and speed. If i feel the bit grabbing, I back it off, let it rotate a few rpm to clear and lower the bit a tad. Holding the work strikes me as very dangerous, but it let's me gauge that goldilocks with great accuracy.

I also do the same on the lathe for my pole work (Xmas tree stands).

Perhaps I lucked out on the Carbitool bits.... I've found them quite good... They have done a LOT of work.

Originally Posted by Evanism

-- mount the big 100mm dusty hose overlapping the hole, with the lip on the shaft of the bit and EVACUATE those chips the instant they form. Suck it all out. Retained chips and dust = heat.

Yes, excellent point Ev, particularly as the hole gets deeper.

Hello again everyone – a status update for those following.

I’ve persisted with my endeavor and have now nutted out 46 candle holders. Still going to do a few more, but I needed 45, so pretty happy about that.

My process has evolved over the last few weeks to where I can now consistently batch them out – it’s still slow, but at least its progress.

I initially started by just grabbing a 41mm forstner and having at it. That didn’t work very well, so bought some sawtooth bits and grabbed the 41mm out of that set and just drilled straight down – I managed to get about 10-12 done this way, with no sharpening or really any care to what I was doing. The end result of this is that 41mm bit is many shades of black and blue as I’ve burned the hell out of it.

Jump forward to today. The process now uses 5 – 6 bits starting from 41mm and stepping down a size. I start with the smallest bit, which I think is around the 25mm and drill down to my required depth. The smaller bit makes short work of it and with my crappy drill press takes about 30 seconds.

Now I change the bit over to the next size up and drill down to the depth the first bit made and then repeat this process until I finish the hole off with my burnt to crisp 41mm bit.

I came across some issues where the bits would grab and it would move my piece of wood ruining my alignment, so I found just a quick spray of the fix-all WD40 helped that out.

Now I’m sure pretty much everything I’ve done hasn’t been the correct way, but I certainly learned a lot about drilling end grain and I think the end result looks pretty good.

WP_20150312_004.jpgWP_20150312_002.jpg

You're getting a result, which is good.

Please don't take this the wrong way, but there's a purchasing lesson in using 4 or 5 bits. It's often said on these forums that buying once and spending the dough required is cheaper than buying twice (and the difference in the two amounts spent is the cost of the first cheapie set). Spend the dough on one good quality bit suitable for the job, use dust extraction when drilling (even an old vacuum cleaner will help), and you should be able to do it without burning- in much less time too.

Originally Posted by FenceFurniture

You're getting a result, which is good.

Please don't take this the wrong way, but there's a purchasing lesson in using 4 or 5 bits. It's often said on these forums that buying once and spending the dough required is cheaper than buying twice (and the difference in the two amounts spent is the cost of the first cheapie set). Spend the dough on one good quality bit suitable for the job, use dust extraction when drilling (even an old vacuum cleaner will help), and you should be able to do it without burning- in much less time too.

No offence taken. For most things I do follow that philosphy. My issue with this situation was time. I needed a large sized bit which are not easy to find locally. The sets were $65 each which isn't the end of the world and i'm still left with a lot of various sizes I will surely find use for in the future.

Regarding dust extraction, I did have my shop vac set up with the hose right next to the bits as I was drilling.