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2-1/2" (or so) self feed bits - which one should I get?

7K views 10 replies 9 participants last post by  altendky 
#1 · (Edited by Moderator)
I plan to be 'drilling' 10-20 holes around 2.5" diameter by 7.5" deep in some logs to use them as vases. It would seem that there are at least a few options for the self-feed forstner-like (sawtooth? not sure the right term) bits. DeWalt, Irwin, FISH (@Woodcraft), WoodOwl… Can anyone offer recommendations on how to pick one? DeWalt seems perhaps the cheapest at $20 while the Irwin (locally at least) is the most expensive at over $40. The Irwin does have the cutting flutes which seems like it could be a good thing, but any personal recommendations?

I do have a 1/2" floor drill press, hopefully that'll be sufficient to keep this from being too painful.

Thanks for your thoughts and have a great day.

Cheers,
-kyle
 
#3 · (Edited by Moderator)
Making vases out of wood.
Would that mean you will be drilling into end grain.
If so, that's going to be tough.

Why a self feed bit? Forstners are not normally self feed.
For a deep hole like that a ship auger comes to mind, but I never saw one that big in diameter.

Main requirement for the drilling machine and self feed bit is to keep the RPM very low.

I think I'd try it with a series of smaller holes made with a ship auger, in a circular pattern close to the outside of the desired diameter and then bust the rest out with a spade bit. Finally clean it up with a forstner.
 
#4 ·
You will need an extender to drill that deep. My Porter Cable Forstner bits have held up well for me. Drill speed for that big of bit needs to be slow. Somewhere there is a chart for recommended drill speed for various diameter bits but I can't remember where.
 
#5 ·
Can't advise as to brand, but I know self feed bits can be dangerous, if they pull the bit into the wood and then hang up. I'd want a solid grip on the material if you use a bandsaw. If you use a portable drill, like a 2 speed DeWalt, Milwaukee Hole Hawg, or Black and Decker (very old industrial model), the lower speed has a clutch to save your wrist from a hung up bit. People have broken their wrists on drills w/o clutches.

On the other hand, if you're going into end grain, the opposite problem may occur: the screw will just chew a tapered hole, and the bit will be reluctant to cut. I'd want that bit to be super sharp.
 
#6 ·
altendky, I would not use self-feed bits in a drill press. They weren't designed for that use. They are designed to make big holes in soft wood (like construction grade lumber) with a drill that is portable. Milwaukee Hole Hawg or Black and Decker Timber Wolf are two speed (with a SLOW low low gear) portable drills with high torque meant to spin those drill bits. As stated above, you will need an extension as they do not make a 2 1/2 bit with a 7" capacity (not that I have ever seen anyway).

The two main problems I see with using a drill press and self-feed bit is 1) Not a lot of DPs have a reverse. With a hole that big and deep, you are going to want to extract the bit multiple times to clear chips (or you may never remove the bit) Without a reverse on the DP, the coarse threads of the self-feed will dig in and may nit be able to be extracted by hand power. In brief, you will have a stuck bit. 2) with a self feed bit, which is a much more aggressive cut than a forstner bit (which has no self feed mandrill) , you are going to need a SOLID hold down for the stock. Last, does your drill press even have 7.5" of travel in the quill? If you are drilling end grain, gonna be even more difficult.

I wish you luck.
 
#7 ·
Heed the advise given above, It's pretty much bang on.
In particular, Mikes advise about NOT using it in a drill press. DON'T. Your only asking for trouble with a self feed in a drill press, especially with a 2 1/2" diameter.

On to hand drills. Don't use a cordless drill with a self feed that size. It probably won't have torque needed and even if it did, you'll end up damaging it.
In our shop we use self feeds with a Milwaukee corded drill. 1/2" chuck, 5.5 or 6 amp and somewhere around 600 rpm?
Aptly nicknamed…."The armbuster"!
Your in for an 'awakening' in regard to how aggressive these bits are, and how much of a workout your in for!
 
#8 ·
As per usual, thanks all for the great replies. I had directed my question at the self-feed because when I searched here for questions about large diameter and deep holes and that's what I ran across (apparently I was missing something though). I had expected to have to combine quill travel with table travel to get the full depth and of course burying the chuck would have caused more hassle with chip extraction (have to stop release blow/vacuum, etc…). Though it's obvious now, I did not think about having to unscrew the self-feed portion of the bit (I'm pretty sure I don't have reverse).

My cordless is a Milwaukee, but an M12 so no worries about me thinking that could do anything to help. :] I do have a big old corded Milwuakee so I'll have to dig it out and see what model it is re: the safety clutch. Regardless, I've kicked a few drills out of my hands (or at least knocked them up) so avoiding that risk all together sounds like a good idea.

I also expected that regardless of tools and technique I would have to attach the log to something more clampable. Either just accept a number of screw holes in the bottom or cut the pieces long and sacrifice the end.

It seems that Forstner bits would be a better option, though still with their significant hazards at that diameter. The multi-drill ship auger approach is starting to sound best. I plan to put inserts in (and it's the inside anyways, and for personal use, not sale) so a pristine interior is far from required. I may route the top so it's clean but the rest could be done by way of following the swiss cheese effect with a larger (spade was mentioned) bit after clearing the majority of material with a 'small' (3/4" or less?) bit and/or perhaps a longer chisel. For this I would expect to use either the drill press or my more manageable Craftsman corded drill. Would the self feed on the ships auger bits still be a significant issue on a drill press at the smaller diameter? I really sort of hope to use the press because I would expect it to leave me a lot less achy the next day (and less fatigue usually means safer when doing the work as well).

So, now that my original question is no longer particularly relevant thanks to all the advice… am I on the right track with an auger bit in the drill press (or spade if auger is no good in the press) followed by a larger one and a bit of chiseling around the edges? Of course, with the smaller bits I can't dip the chuck into the hole so the bit must be full length.

Thanks to all and have a great day. I'm sure you've saved me a few horrible, frustrating, and dangerous days.
 
#10 ·
I have used a large chuck on the lathe to hold the round stock, and put a 1/2" chuck mounted on a
morse taper adapter into the tail stock to hold the bit. I have a jackshaft on the lathe to get real slow
rpm, and the tailstock feed gives me lots of control on a self feed bit. I back it out often enough to
keep the chips clear, and Milwaukee has excellent extensions for their hole hawg that I can use to get
a longer reach. Do not know if you have a lathe, but with the right accessories they are wonderful
tool.
 
#11 ·
The bandsaw idea is interesting. If nothing else, I've been seeing the bandsaw box projects recently and have been meaning to see what the technique was. Now I know. :] With the inserts I expect to use the bottom is of no particular relevance. A slice in the side might be able to be covered or otherwise left open which might alleviate the need to get the logs dried?

I do also have access to a mid-sized lathe and have considered that option as well. I may end up trying a few of these ideas before they are all done. If nothing else, it will break up the repetition.
 
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