Drill Press deflection

[Tom Hammond]

I use my drill press quite a bit. I've noticed, and try to compensate for, that grain of hard woods like oak can cause drill bit deflection. I can actually see the bit tip trailing to one side as I begin the plunge into the wood. This causes inexact positioning of holes. It might be minute for some applications, but I make stackable bookcases that require precision on the placement of the holes. Any advice? This happens, seemeingly, to any bit up to about 3/8", but not to Forstner bits. Are there special bits made just for drill press use?

THANKS!

[Van Huskey]

Sounds like you have deflection in the quill since it is unlikely a 1/4" bit would bend... If you have quill deflection it is unlikely you can adjust it out unless your DP is a split head design. You may be able to reduce runout by dropping the chuck and cleaning the taper. Deflection gets worse as quill travel increases so you may be able to move the table up so you are drilling with the the chuck the least distance from the drill head. If forstner bits don't deflect you may increase your luck with brad point bits or just start the holes with a sharp awl or similar tool. Further I am not sure what size you need but if all else fails they make forstners down to 1/4" but most forstners today have a point but they are pretty sharp and are less likely to deflect.

[John Coloccia]

You can use a "starter" bit to start the hole. This is a VERY stout bit and will not deflect, usually combined with a countersink. I'm not sure why they combine it with the countersink but when I was doing metal work I DID find it useful to start the pilot and countersink in one step...it ensured that the countersink is coaxial with the hole.

Anyhow, here's an example of what I'm talking about.
http://www.harborfreight.com/5-piece-center-drill-countersink-set-with-60-angled-tip-42280.html

Brad point bits help too, though you wouldn't use a starter dill with those as you're taking away the wood the brad point needs.

[Terry Welty]

+1 Brad Point Bits.... Go slow on pressing the bit into your wood.

[Rod Sheridan]

Tom, are you using twist drills which are meant for metal?

As Terry indicated brad point bits are made for wood and won't have that problem.

Also a center punch mark made using an awl by hand will help start the bit off in the correct spot...........Regards, Rod.

[Lee Schierer]

+1 Brad Point Bits.... Go slow on pressing the bit into your wood.

+2 Brad point bits work better than twist drills in wood. You can also lightly tighten the quill lock so that it is tighter on the quill but not stopping movement to take out some of the play.

[Thomas Canfield]

+ for Brad Point bits for wood. Additionally, check your drill speed. Too often, we get lazy and do not increase the speed for the smaller diameter bits to improve their drilling to let the bit cut the wood. CAUTION - make sure that the speed is decreased before going back with larger bits. Changing the belts on my 2 belt Delta does take some time, but you get used to it.

[glenn bradley]

Brad point bits will cure the wandering via the center point. Look at the bits you are considering carefully. Many profiles are called "brad point" and rightly so. Some profiles are definitely better than others. FWW Review, 8 brands, 8000 holes, surprising results: http://www.finewoodworking.com/fwnpdf/011180050.pdf Check other reviews as well. Your intended use will govern your satisfaction with a given profile. I like Lee Valleys 'lipped' version but there are several really good versions (although much fewer than poor versions) out there.

[Tom Hammond]

Thanks guys. Good input. I am definitely using wood bits. I am wondering if they make brad-point bits as small as 1/8" ??

[glenn bradley]

Thanks guys. Good input. I am definitely using wood bits. I am wondering if they make brad-point bits as small as 1/8" ??

One of my sets starts at 5/64". Fuller and other known quality makers also seem to start at 5/64". Maybe there is something to do with the tip geometry and the minimum diameter that will support a usable spur(?). Pure speculation ;-)

[Chad Bender]

I've got a Lee Valley BP at 5/64". No 1/16", although there was an empty hole in the box the set came it.

[Jerome Hanby]

Thanks guys. Good input. I am definitely using wood bits. I am wondering if they make brad-point bits as small as 1/8" ??

My woodcraft red metal box set goes down to 1/16"