Drill Press Precision

[Tom Bender]

Was having trouble getting holes in the right place, off by up to 1/16". I have a project that needs to be closer so I took time to improve.

A. my secondary table is not perfectly flat so I set it aside and may make a better one, but for now I can work with the cast iron table.

B. typically I put a flat board on the table to back up the hole. My best one was not real flat so I flattened it.

C. I will be using a forestner bit so I decided to skip the backup board and line up with the hole in the cast iron table and set the stop to just poke thru. This worked better than a pilot hole which tends to wander and the back drilling did not line up well.

D. a dial indicator showed that pressure on the table caused it to flex .002" to .005" so I'll stay on the low side of that by going slowly.

E. Center punching accurately got better when I sanded the wood first. And a shallow knife cut helped a lot, but not crossed cuts. For some reason crossed cuts let the punch drift off.

The result was a good hole within 1/64"

[Bill Dufour]

It is quick and easy to check spindle runout on a drill blank held in the chuck. I try to get it under 0.003". If I use a big drill and jam things up it can bend the spindle off by 0.005 or more.
Bill D

[Jim Becker]

Sometimes, removing and reseating the DP chuck gets thing back to where they need to be. Many DPs come with a triangular piece of metal that's designed to help you remove the chuck from the taper. My Jet came with one and I did do the reseat process a number of years ago to tweak things.

[David Buchhauser]

I find it helpful to clamp the work piece to the drill press table before drilling. I have also found that my typical drill press chuck runout (TIR) is around 0.003". This is actually pretty good. I have also found that using the Irwin speedbore style bits in a drill press makes it hard to keep them centered. I expect the Forstner style to work better for this situation.
David

[Tom Bender]

DOH while I had the dial indicator set up I didn't think to check runout. I can also check runout on the bit. It's Forstner style, not Forstner brand so there's that.

Clamping to the table means aligning the part with the bit, not so easy especially with a Forstner style bit. This is necessary for big workpieces but for lighter work I let the bit push the part into alignment with the center punch.

[Charles Coolidge]

Discover centering scopes when the hole must be precisely where you want it. This scope is 40x power.

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[Tom Bender]

A cantering scope! genius but at a cost.

[Randy Heinemann]

Seems like overkill for woodworking. After market lasers are cheap, are made to mount on the drill press and locate where the drill bit tip will touch the wood once adjusted. Wixey makes one for $35 - $38 depending on where you buy it. It is available on Amazon. It locates where you want to drill easily as accurately as is required for woodworking. Even that may be overkill.

[Bill Dufour]

In a bin of drill bits from the flea market I got several interesting bits. One was about 3/8" diameter. One end has a long cone from 3/8" down to a point over about two inches. I chuck it up and use it to find a hole ,location before drilling. Being so long and slender it allows light and easy sight lines. The taper allows better determination of the center then the old finish nail in the chuck method. A 1/2 or 1/4 inch one would be nice in a plunge router, I supose.
Bill D.

[Charles Coolidge]

A cantering scope! genius but at a cost.

After I login to my MSC account the centering scope cost drops 55% to $204.30. For those of us with older eyes who have difficulty lining up to a pencil or punch mark these are genius!

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Centering on a mechanical pencil mark.

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[Lee Schierer]

When you need precision: Keep the quill in the drill housing as much as possible. Move the table up so the work piece is not quite touching the spur on the bit. Set your rpms up a little for the entry cut, once the hole is started you can slow down to normal speed. Bore the hole depth slowly allowing the cutter to cut more evenly.

[Tom Trees]

I've been having issues with my setup also.
Seems that pretty much most folks who use a pillar drill accurately have an XY table.

I've just got a basic pillar drill, and no fancy cross sliding vice, no dial indicator and just a wee Liddles jobbie which is infact pretty good
Done all the cheap tricks and still getting issues...
i.e tramming with a bent bar, and short one to level the table a whole lot better than an engineers square
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And been centring the bit in pre bored part of the work to lock everything down, the work faced on a mandrel the lathe previously
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Think I've got to the bottom of things now, two things were missing from my setup

The first issue, the table was flexing.
The second and arguably more important is the lack of indexing when needing to change bits!
(which if you've got an underpowered machine or just one with loose belts for whatever reason, likely amplify this)

Will be pottering about with what I hope will the solution to both those issues for the next while.

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Looks like I'm gonna have to get used to the rigging up the vise the other way round
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Hopefully this will be sweet as a nut, and my troubles will be over.

Might have to make or buy a centring cone like Bill mentioned, should something with say a 10mm shaft be bought off the shelf for some application
which isn't engineering, as I don't have a chuck to make one?
Love to know that if someone has found something like that

Cheers

Tom

[Randy Heinemann]

After I login to my MSC account the centering scope cost drops 55% to $204.30. For those of us with older eyes who have difficulty lining up to a pencil or punch mark these are genius

I am older and have never had great eyesight. The Wixey Laser for the drill press works great once lined up and that cost is about $38. I would guess that the centering scope is needed for metal work (I'm not a metal worker.) Woodworking doesn't require the same level of precision since wood moves at least seasonally. With the laser I can easily see where the drill point should be and quickly drill the hole. I would guess the precision is much better than 1/128" and I can't think of anything that requires better precision than that in woodworking; making furniture, cabinets, or jigs for the shop.

[Charles Coolidge]

I am older and have never had great eyesight. The Wixey Laser for the drill press works great once lined up and that cost is about $38. I would guess that the centering scope is needed for metal work (I'm not a metal worker.) Woodworking doesn't require the same level of precision since wood moves at least seasonally. With the laser I can easily see where the drill point should be and quickly drill the hole. I would guess the precision is much better than 1/128" and I can't think of anything that requires better precision than that in woodworking; making furniture, cabinets, or jigs for the shop.

The woodworking I do requires precision layout and drilling, guessing at close enough doesn't cut it. No less precision than I demand of my other woodworking machines. If a laser pointer works for you great, but your personal situation does in invalidate the centering scope as an essential tool for others.

[Richard Coers]

If you look for optical centering punch it gets you in a different price range. $53 from Grizzly. https://www.grizzly.com/products/grizzly-optical-punch-set/h5781?gclid=CjwKCAiAgvKQBhBbEiwAaPQw3GnoAOlucl-FAIfpAzPlKbRobBeZkeFBcYQsJUeIKSLPoRn1gLFlSBoCpbUQA vD_BwE

[Andrew More]

Couple of suggestions.

1) I've got an old Craftsman, with a spindle lock. If you don't have one, they seem fairly rare, you can skip this. Anyway, I put a bit in, lower it to the table while the press is OFF, then lock it down directly in contact with the work piece, at the place for the hole with the spindle lock. I then proceed to clamp the work piece to the table. Once this is done, I release the lock, disengage it from the piece, and then turn on the power, and now drill the hole.

2) Since I've got this old craftman (from the 1970s) it had seen a lot of use, and had terrible run out. I replaced the chuck which helped some, but still not perfect. Managed to damage the taper with the new chuck, replaced the new chuck with an exact copy of the original. Now works fine without runout and I was thinking I'd need to replace the bearings. So check the chuck and make sure the bit is correctly seated within the jaws if you've got a press that's seen some use.

[Randy Heinemann]

The woodworking I do requires precision layout and drilling, guessing at close enough doesn't cut it. No less precision than I demand of my other woodworking machines. If a laser pointer works for you great, but your personal situation does in invalidate the centering scope as an essential tool for others.

It's wood, you know. I am a perfectionist. I have equipped my planer with a digital gauge. I have a drum sander with a digital gauge. I actually installed an add-on digital depth gauge to my drill press. I have found that, while I get the mental satisfaction I'm getting the highest precision I can get, the result isn't really better; just seems better. I'm not sure what you're making, but the accuracy and precision I get from these add-ons is really kind of overkill. But, if the centering scope precision gives you satisfaction, that's great. After all, that's what making furniture, cabinets, etc. is all about - satisfaction and enjoyment - at least for me. Plus, I'm not criticizing. I have spent money on tools that I think give me more capability, accuracy, or precision just for the satisfaction of it.

[Larry Frank]

The woodworking I do requires precision layout and drilling, guessing at close enough doesn't cut it. No less precision than I demand of my other woodworking machines. If a laser pointer works for you great, but your personal situation does in invalidate the centering scope as an essential tool for others.

Just wondering what you make.that requires that level of precision?

[Charles Coolidge]

Just wondering what you make.that requires that level of precision?

The 'precision' starts early and continues through the wood cabinetry...Behold the stainless CNC laser cut chassis and TIG welded corners. Made in USA

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The CNC milled, drilled engraved/infilled black anodized aluminum face plates. Made in USA

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The over the top custom .125 inch thick turret/PCB boards in stout 2oz copper with plated through holes.

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Awaiting wood cabinetry...

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[Andrew More]

Sorry, looked at the pics and I'm still mystified. What is it? Tube app?

[Tom Trees]

Had a rethink of the hard stop/index, as there would be a lot more potential for slop, and besides I like the table easier to check and vise where I have it.
Seems the knee was made for jiggery ;)
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Tom

[George Yetka]

A sharp awl or centering punch will help line up the bit and mitigate wondering in smaller brad point bits.

[Charles Coolidge]

Sorry, looked at the pics and I'm still mystified. What is it? Tube app?

Indeed, that's a Dumble ODS inspired guitar tube amp. :D That thing was a bear to build, Marshall's way easier.