sawtooth or forstner bit?

[dedee]

I'd like to bore some 2" holes about 4" deep in hardwood (probably oak and chestnut) to make an enclosed cylinder. I only have a drill press, no lathe. Which would be most suitable the forstner or sawtooth?

Cheers

Andy

 

[OPJ]

I think sawtooth cutters are better-suited for hardwoods. Saying that, I'd expect either one to 'struggle' cutting 50mm holes at 100mm deep... What I mean is that you will need to stop and clear waste from the bit fairly often. An auger would do the job much quicker but, they're not really suitable for stopped holes or for use in a pillar drill, in my opinion.

Have some ear defenders handy as they can squeal a bit, too! :wink:

 

[woodbloke]

I'd agree with Olly, saw tooth cutters are better but they cost a bit more. You'll also need a fairly powerful pillar drill, the little hobby one that I've got will just cope with 25mm in hardwood but would certainly struggle with a 50mm hole - Rob

 

[DaveL]

Andy,

I have not drilled 2" holes but in hardwood I find this sort of bit works well for deep holes

I have a boxed set of metric ones while that one is 3/4" and came from Tilgear. I have seen them in bigger sizes but can't remember where.
Olly bought an Armeg Wood Beaver bit

to drill his dog holes, Axminster do a set but not that big. I have found a 32mm one on ebay, it might be worth doing a proper search?

 

[wizer]

Whatever you do don't buy a cheap one. I have some cheap forstners that cope OK with most stuff. But the 50mm one is near to useless. I can barely get 5mm before it just burns the wood and stalls the drill.

 

[thomvic]

I have a set of Record saw tooth bits 1/4" to 2 1/2".

As some others have observed - no good in a small pillar drill. However, I managed very well with 2 1/2" diameter 4" deep in oak on my morticer chuck. Just go very slowly, clearing shavings frequently. I have also drilled that size with may mains powered hand drill.

Richard

 

[dedee]

My drill is rated at 250w and states max drilling diameter is 13mm. It managed quite well to cut 40mm holes 13mm deep in hard wood, all be it very slowly using a Bosch forstner bit.
I guess I might have to try in order to find out if the drill can cope.

Would holes drilled in the side of the cylinder aid with chip clearance? Anything up to about 10mm could double as a design feature.

Those Armeg drills do stop at 32mm. Interesting website though.

Cheers

Andy

 

[OPJ]

Before buying one of the Wood Beaver bits (which I wouldn't recommend for pillar drill use as they race through the hardest of woods! :shock, I did try drilling 6mm pilot holes for a ¾" forstner. Sadly, it didn't make any difference and I had to keep stopping to clear the bit.

If the holes weren't as deep then you could've done them with a router and template.

 

[dedee]

However, I managed very well with 2 1/2" diameter 4" deep in oak on my morticer chuck. Just go very slowly, clearing shavings frequently.
Richard

Is the morticer a wee bit too fast for a 2 or 2 1/2" bit. From memory I think mine is 3000rpm and I have scorched wood before using it with much smaller bits.

Cheers

Andy

 

[DMD]

did you mention oak wet or dry ? I paid £40 for my 50mm forstner but it really works, saw drills leave a lot of clearing up.

 

[xy mosian]

Hi, I was chatting with Dave R last evening and this problem cropped up. Both of us agreed it's a tricky one.
But. How about treating it as a round mortice. Drill out most of the waste with something crude and fast. 1 1/2" flat bit say, then clean up with sawtooth or forstner bit, that way you have much less waste to clear. Of course you loose the centre once you use the flatbit. So.. start off with the forstner to say 1/2", drill out the waste, then return to the forstner to clean up using the outside of the bit for reference. This should also take some pressure off the dilling machine.

xy, after chat with Dave R

 

[dedee]

XY, the oak/chestnut will be dry. I've no issues with buying a quality forstner bit £40 for a 2" bit does not seem excessive. Which one did you get?

XY and Dave R. I've been mulling this over and in fact came to the similar conclusion ie using the mortiser to clean out most of the hole and then finish with the 2" bit in the drill.

Cheers

Andy

 

[SketchUp Guru]

DeeDee, as XY and I talked about it, we were thinking you could drill out most of the waste with a standard drill bit as you might if you were chopping a mortise by hand. Just don't drill out the center so you can identify it when it comes to running the Forstner bit down.

 

[xy mosian]

Yes. Sorry Dave I had forgotten that bit

xy

 

[SketchUp Guru]

XY, no worries. I thought you covered it well.

 

[Keenedge]

I've used famag bormax bits on oak end grain at 50 mm with no problem, couldn't do it with a standard forstner bit though.

 

[dedee]

Thanks keenedge,
I've not heard of famag before but the design looks interesting. Of 18 different sizes in the Rutlands catalogue guess which one is out of stock!!

Cheers

Andy

 

[Keenedge]

Isaac Lords? Any decent tool shop should be able to access most quality ranges and the internet ones as well. Ask whoever you normally use to get it for you.

 

[dedee]

Thanks they are indeed in the Isaac Lords catalogue.

While I await the 50mm bit I though I'd prep the timber and bore out most of the hole. This is chestnut, a reclaimed post from the garden.

First time that the mortiser has been used (or even unpacked) since the move 2 years ago. It felt good to be using some boys toys again.

Cheers


Andy

 

[dedee]

What I bought was one of these from Dick

http://www.dick.biz/dick/product/707387/detail.jsf

I also bought the 300mm extension bar that was way too scary to use. With the drill bit on the end the wobble was excessive. I had to use it in the mortiser to get the depth of cut and perhaps 3000rpm was a bit too fast.
It tuned out that with the length of the drill plus the length of the chuck I was able to drill to a depth of 75mm which turned out to be adequate.

BTW great delivery service from Dick if only DHL could sort out their Sat-Nav as they can never find our road.

Cheers


Andy