# drill press problem

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• posted on November 8, 2011, 8:13 pm
In the course of making a hammered dulcimer, I needed to drill some holes at 38 degrees for braces between the two pin blocks. After much muttering and adjusting, I got the table to lock down at that setting. But when I drilled the holes, I found that tilting the table to 38 degrees in one axis also tilted it 2-3 degrees in the other axis. That means the braces won't fit from one pin block to the other.
Now I'm trying to figure out what happened. OK, it could just be a faulty drill press and I'm SOL. But I'm wondering what if the table was not exactly centered under the head. Since both swing independently, it's possible for that to happen. And I had to swing both 90% to avoid hitting the base (it's a benchtop drill press, albeit an old heavy one).
But my geometry visualization skills aren't of the best. If the head and table weren't on the same exact vertical (Z) axis, would a change in the parallel to the shaft (X) axis result in a change in the perpendicular to the shaft (Y) axis?
I've filled the holes and am waiting for the glue to dry. If the centering is the problem, I'll get everything lined up and try again. If not, I'll find another way to install braces - I've already figured out one or two alternatives.
While I'm on the subject of drill presses, does *anyone* make one that doesn't require loosening a bolt to tilt the table? I've looked at Delta, Jet, Powermatic, Shop Fox, etc. and they all use a bolt and a pin to force 0 degree alignment.
I'm seriously thinking of getting a radial arm drill press when I can afford one, but I've heard that they aren't too accurate because of too much flex. Is this still true? Or mayde still true for some and not others?
--
Intelligence is an experiment that failed - G. B. Shaw

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• posted on November 8, 2011, 8:35 pm
On 11/8/2011 2:13 PM, Larry Blanchard wrote:

Bolt as in need a tool to make the adjustment? My Delta requires a tool in for left /right tilt but has built in bolt loosening levers for the tilt of the table front to go up or down.

I had an old Rockwell radial DP, it was a good DP but was short on features. One thing that may be inherent and I don't like is adjusting the drill head to have a longer reach. It is not a smooth action. As you extend the head out and the motor comes closer to the vertical shaft the whole thing binds. You have to lift and pull or push...
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• posted on November 8, 2011, 8:56 pm

A couple of possibilities. 1) There was a shim in the table rotating mechanism that fell out when you rotated the table. 2) The plane of the rotating mechanism isn't parallel to the quill axis. Art
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• posted on November 8, 2011, 9:24 pm

I don't know the luthier terms so I don't know exactly what your part looks like but if when the table is flat and the part is aligned exactly 90 degrees to the axis of post to the drill head, then if the table rotating axis was not also exactly 90 in that same axis, rotating it will change to the incident angle of the drill to the part in the perpendicular axis as well, so yes a slight misalignment could easily introduce 2 degrees of change.
Even if you are certain the table is aligned, I would still check the alignment once it is rotated up to the 38 degrees. You should be able to square off the drill head somewhere to be sure the part is perpendicular.
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• posted on November 8, 2011, 10:33 pm

I never go straight to working on my "good" pieces, I always have some scrap or extra rough duplicates to test angles, depths and other potential problems. I would rather destroy the cheap wood rough pieces or scrap wood trying to get it right than risk damaging my final good piece.
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• posted on November 9, 2011, 12:09 am
YES... you are right if they are not aligned you would introduce error.
To fix this problem I suggest a few tricks. Bend a wire in a Z shape, but more like L's . Make the bottom L as long your drill bit distance, plus piece size to be drilled after tilting the table.
Mount the wire in the drill press. Mark where it touches the table on each side of the table. Draw a line between the two marks. That is your aligned center line. Your piece if square must be on or parallel to that line.
On 11/8/2011 3:13 PM, Larry Blanchard wrote:

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• posted on November 9, 2011, 2:57 am
You could also get a digital angle gauge, like the Wixley Gauge at Woodcraft. Not so cheap, but might have other uses around the shop.
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• posted on November 9, 2011, 7:29 pm
On Tue, 08 Nov 2011 18:57:29 -0800, scritch wrote:

I have one and used it on this. But it doesn't like being tilted perpendicular to its face.
--
Intelligence is an experiment that failed - G. B. Shaw

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• posted on November 9, 2011, 12:09 am
YES... you are right if they are not aligned you would introduce error.
To fix this problem I suggest a few tricks. Bend a wire in a Z shape, but more like L's . Make the bottom L as long your drill bit distance, plus piece size to be drilled after tilting the table.
Mount the wire in the drill press. Mark where it touches the table on each side of the table. Draw a line between the two marks. That is your aligned center line. Your piece if square must be on or parallel to that line.
On 11/8/2011 3:13 PM, Larry Blanchard wrote:

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• posted on November 9, 2011, 11:41 pm

Can't help with the issue, but if you want somethign really nice to drill and work with, check out a mill-drill or even a used Bridgeport.
I only mention these because you mentioned the radial arm unit, which is probably large and expensive to begin with but very low on additional features.
--

Regards,
Joe Agro, Jr.
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• posted on November 10, 2011, 9:46 am

I'm looking to get one of these in the new year:
http://www.warco.co.uk/milling-machines/37-major-gh-milling-machine.html
I've had an X-Y table on my ancient drill press for a while and it makes life very easy. Clamp work to table or in vice and move to the exact point where I want to drill the hole - several holes in a line on the same piece of wood, easy-peasy. The 130mm spindle travel is better than many drilling machines I have seen and I have the capability to mill metal too
--
Stuart Winsor

Only plain text for emails
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• posted on November 10, 2011, 6:10 pm
On Wed, 09 Nov 2011 18:41:38 -0500, Joe AutoDrill wrote:

I'm afraid a Bridgeport and its ilk are well out of my price range. But there are a few inexpensive radial drill presses out there. Rikon makes both a bench and a floor model:
http://www.rikontools.com/productpage_30-140.htm
Grizzly and Shop Fox make similar units and there are probably others. Grizzly also makes a somewhat different unit:
Any comments on these from owners?
--
Intelligence is an experiment that failed - G. B. Shaw

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• posted on November 10, 2011, 6:18 pm
On 11/10/2011 11:10 AM, Larry Blanchard wrote:

what are you going to use the radial drill press for? i've seen people dismount the drill head from the support, mount the support on the ceiling, upside down, and remount the head. that gives them a longer throw, for drilling long things. this doesn't give you the sideways drilling capability though.
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• posted on November 11, 2011, 2:26 am
http://www.grizzly.com/products/Mill-Drill/G0463 would be a better choice. Column moves up down and is always square with the drill point.
The issue with round columns is they loose registration. They rotate.
If you move in and out of the column, the drill might be at a slight angle of 2 degrees - or 5 degrees...
It is flexible - able to move in all directions - but alignment is hard to keep up with.
Martin
On 11/10/2011 12:10 PM, Larry Blanchard wrote:

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• posted on November 11, 2011, 2:52 am
On Thu, 10 Nov 2011 20:26:17 -0600, Martin Eastburn wrote:

You guys keep trying to spend my money :-). I might be able to afford a \$300 DP, but that's about my limit.
And even the non-radial (i.e. normal) can lose registration, in the sense of the table still being centered under the bit and at 90% to the column, every time the table is raised or lowered. That's what caused my problem in the first place.
BTW, I got my DP "re-registered" and redrilled my 38 degree holes - worked pretty good this time. About 0.2 degrees off of perfectly vertical, which was well within tolerance for the project.
But I'm still considering budgeting for a low end radial DP.
--
Intelligence is an experiment that failed - G. B. Shaw

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• posted on November 11, 2011, 10:07 pm
"Larry Blanchard" wrote in message
On Thu, 10 Nov 2011 20:26:17 -0600, Martin Eastburn wrote:

You guys keep trying to spend my money :-). I might be able to afford a \$300 DP, but that's about my limit.
And even the non-radial (i.e. normal) can lose registration, in the sense of the table still being centered under the bit and at 90% to the column, every time the table is raised or lowered. That's what caused my problem in the first place.
BTW, I got my DP "re-registered" and redrilled my 38 degree holes - worked pretty good this time. About 0.2 degrees off of perfectly vertical, which was well within tolerance for the project.
But I'm still considering budgeting for a low end radial DP. --------------------------------------------------------------------------------------------------------------------------- Do yourself a favor. Tram your table square and leave it there. For angles, build a fixture.
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• posted on November 12, 2011, 12:29 am
"CW" wrote:

---------------------------------- Sounds like a winner.
I had my table brazed in position to eliminate one axis of registration problems.
Lew
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• posted on November 12, 2011, 5:49 pm
On Fri, 11 Nov 2011 14:07:39 -0800, CW wrote:

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I had considered that. Building an adjustable fixture that handles multiple angles is just re-inventing the drill press table. And I doubt I could get any better accuracy than a factory full of CNC machines. Especially with wood rather than metal. You, and others, *might* be able to, but I don't think I am.
I could probably get acceptable accuracy with a dedicated fixture for each angle needed, but that's a lot of work and eventually a lot of storage.
And neither solution fixes the problem of drilling a long piece at a steep angle where the base of the press or even the floor gets in the way.
So it boils down to how much angled drilling I'm going to be doing. If I continue to be intrigued with building old-time musical instruments, it'll be quite a bit. Or if I get into making chairs. If I go back to my old ways of making boxes, chests, and cabinets my current press will do fine.
Thanks to everyone for all the help.
--
Intelligence is an experiment that failed - G. B. Shaw

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• posted on November 12, 2011, 7:19 pm
"Larry Blanchard" wrote in message
On Fri, 11 Nov 2011 14:07:39 -0800, CW wrote:

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I had considered that. Building an adjustable fixture that handles multiple angles is just re-inventing the drill press table. And I doubt I could get any better accuracy than a factory full of CNC machines. Especially with wood rather than metal. You, and others, *might* be able to, but I don't think I am.
I could probably get acceptable accuracy with a dedicated fixture for each angle needed, but that's a lot of work and eventually a lot of storage.
And neither solution fixes the problem of drilling a long piece at a steep angle where the base of the press or even the floor gets in the way.
So it boils down to how much angled drilling I'm going to be doing. If I continue to be intrigued with building old-time musical instruments, it'll be quite a bit. Or if I get into making chairs. If I go back to my old ways of making boxes, chests, and cabinets my current press will do fine. ---------------------------------------------------------------------------------------------------------
I was going to address each point but you seem determined to continue to stumble along. Have fun.
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• posted on November 12, 2011, 8:03 pm
Go to an engine rebuild shop and get a big old exhaust or intake valve. When you need to square your table, chuck the valve up, loosen the table adjustment screws, bring the valv down to a flat surface of the table, and tighten it up. Accurate enough for most woodworking.
--
When the game is over, the pawn and the king are returned to the same box.

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar.org