Vertical drilling accuracy question.

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Forum topic by markedwardsims posted 10-17-2011 10:37 PM 3084 views 0 times favorited 13 replies Add to Favorites Watch
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50 posts in 2687 days

10-17-2011 10:37 PM

Hello Luberjocks, I need a little help here. I recently took an intro level pen turning class and really enjoyed it. I am now the proud owner of an old Jet mini lathe, and I’m getting started on my first turning projects. I have a Craftsman 34” radial drill press, and I’m noticing that when I drill the hole in a 3-1/2” blank there is some drift of almost 1/8” – 3/16” by the opposite end. I am using a Jorgensen hand screw to hold the blank vertically, and I checked with a combo square to ensure the blank is 90 degrees to the table.

I thought that maybe the drill press table was out of alignment, so I used my digital angle box to take some measurements, and I’ve now got the table squared to the drill bit on both the x and y axis. I even checked the bit at the top and bottom of the plunge, and it is square.

Have any of you guys ever faced something like this? Maybe this is one of those technique things?

Any help is appreciated. Thanks in advance!


13 replies so far

View TheDane's profile


5423 posts in 3656 days

#1 posted 10-17-2011 10:50 PM

Mark … I have had the same problem with my 7mm drills for pen blanks. I have tuned/re-tuned my drill press (even replaced the chuck) with no joy.

The only way I can get them reasonably straight is to use a Jacobs chuck on the lathe and mount the blank in the jaws on my scroll chuck. Sometimes even that doesn’t quite cut it, so I am thinking the bit may be wandering a bit in the grain.

I need to figure this out pretty soon … I want to make some pens with Celtic Knots in them for Christmas presents, and if the hole isn’t perfectly centered in the blank, the Celtic Knots come out cock-eyed (don’t ask me how I know this!).


-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View PurpLev's profile


8535 posts in 3642 days

#2 posted 10-17-2011 11:01 PM

1. what drill bit are you using? smaller drill bit can flex during the cut which can throw them off on a drift.

2. another thing that can throw it off is if the top of your blank is not parallel to the table or perpendicular to the chuck/drill bit which can cause the bit to drift slightly upon penetration which results in the hole entry not being vertically aligned with the chuck causing the hole to drift sideways.

Try using a center punch, or a larger strurdier drill to make the entry hole (shallow cut) and then continue with the smaller bit. this will give your smaller bit a V sink to follow and stay centered.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View markedwardsims's profile


50 posts in 2687 days

#3 posted 10-17-2011 11:03 PM

It certainly feels a little better to not be alone in this situation. My first thought was to just cut bigger blanks, but in the case of a Celtic knot, you’re exactly right. It has to be perfect. I just happened to have a piece of left over tiger maple that it 9/16” thick so I wanted to put it to good use. Fortunately, I’m using a slimline kit for that one, so after I cut the blank in half, the drift still left me plenty of wood to turn from.

I’ll take a look at the Jacobs chuck. Thanks!


View markedwardsims's profile


50 posts in 2687 days

#4 posted 10-17-2011 11:08 PM

I’m using a 7mm bradpoint bit. I think there may be something to the squareness of the blank. I’ll definitely try cutting the blank more square. I actually hand cut it since I don’t have a band saw, so there’s a good chance it was out of square. Does the center punch and larger bit advice still pertain to a bradpoint bit? I thought the sharp point on those things was supposed to keep them on track. Thanks for the reply!

View MrRon's profile


4758 posts in 3237 days

#5 posted 10-18-2011 12:33 AM

Drill the hole in the lathe, not on the drill press. DP’s are not the most accurate of machines, drill bits can wander, especially if they are not ground properly. A 4” long pen blank that is out 1/2° (30 minutes) will throw the center of the hole off by over a 1/32”.

View Mike's profile


406 posts in 2681 days

#6 posted 10-18-2011 12:36 AM

I so don’t understand why so many people want to get 100% accuracy on pen blanks. What I do for a 7mm pen is I make the blank 3/4” square, drill my hole as straight as possible, glue in the tube, take it over to the disk sander and square the ends with my miter gauge. Throw it on the lathe and just clean everything up. I have never had an issue. I feel we think about things way to much.

My thought is, why worry about making it square if your going to make it round in the end?

-- look Ma! I still got all eleven of my fingers! - -

View TheDane's profile


5423 posts in 3656 days

#7 posted 10-18-2011 12:52 AM

I’m using 7mm brad point drill bits for slimline pens as well, ‘dimple’ the center with a punch, and use a home-brew drilling jig made out of a wooden clamp and piece of plywood …

Here’s the jig with a blank I just drilled …

Here’s the other end of the blank … the hole is ‘close’ to the center, but close gets no cigar!

The ‘V’ cuts in the wooden clamp measure out to exactly 90 degrees each way, and one jaw of the clamp is screwed to the plywood. The ends on my blanks also are true 90 degree cuts, and the stock is 1” square.

For the most, this doesn’t create a problem (the blank shown above us pretty close), but the degree of precision needed for a Celtic Knot is such that this blank would not produce a satisfactory result.


-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View TheDane's profile


5423 posts in 3656 days

#8 posted 10-18-2011 01:10 AM

Mike …

I think this picture pretty much illustrates the problem …

Notice how cock-eyed the Celtic Knot is? The center was off by just a very small amount (maybe 1/32”). Each blank for this pen required 30 minutes or more of cutting and gluing. I knew it was off before I glued the brass tube in, but decided to go ahead and turn/finish it to see just how bad it looked.

Judge for yourself.


-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View 1yeldud1's profile


301 posts in 3036 days

#9 posted 10-18-2011 03:38 AM

gerry – Im 36 year tool maker by trade – is the “v” notch in your clamp square with wood that is is mounted to Would it be feasable to drill 1/2 the way thru the pen blank with a smaller diameter bit and the flip the blank over and drill the 2nd side with this undersize bit – then insert the “finish size” drill bit and pass completely thru the pen blank this will allow the drill bit to follow the pilot hole thus minimizing the total runout One must rmember that the grain structure of wood can tend to allow a drill bit to lead off center – Thanks

View TheDane's profile


5423 posts in 3656 days

#10 posted 10-18-2011 02:06 PM

1yeldud1—Yes … the ‘V’ notches are both square with the plywood, and are square themselves.

Drilling in half way with a smaller bit then flipping the blank and drilling from the other end is something I haven’t tried yet … I’ll give that a shot. Thanks for the advice!


-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View rance's profile


4258 posts in 3154 days

#11 posted 10-18-2011 03:21 PM

1yeldud1, that is worth trying.

Mark, No offense, but I would not trust the ‘eyeball method’ for checking to see if your drill bit or blank is vertical. First, check your table for square. I addressed this in another thread . Once you know this is square, then make several pieces of make believe pen blanks(not a pen blank from who knows where) mark the center of both ends and drill one. Take note which side is to the left. Then turn your vise 180 deg. and drill another one, again noting the left side of the blank. If they follow the vise, then your vise is suspect. Do all the steps above with the table locked in place. This can affect its tram.

Drilling at a higher speed was also mentioned, that can help to keep the bit from wandering, especially when first entering the wood. Maybe slow down your rate of plunging into the wood too.

Again, I don’t trust anybody’s ‘eyeball method’ of tramming a drill press. Not even my own. Use other methods for checking square/tramming. HTH. And let us know if/when you solved the problem.

PS: There’s also some good information over at the IAP.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View markedwardsims's profile


50 posts in 2687 days

#12 posted 10-18-2011 04:50 PM

Thanks for all the great feedback guys! I’ve got some homework to do for sure. The good news is that my blanks were large enough that I was able to still get the shape that I was looking for with the off centered hole.

I really like the notches in the thumbscrew, so I think I will add that to my setup and see if I get better results. I also like the pilot hole idea that 1yeldud1 posted.

Thanks as always!


View mtenterprises's profile


933 posts in 2686 days

#13 posted 10-18-2011 05:44 PM

Please take this in the spirit it is offered. My wife often tells me that I am way too much of a perfectionist and that I am my own worst critic. The pen picture you posted looks just fine like it belongs that way. My wife says the customer will never notice and only you as the maker will know. Drilling end grain perfectly is difficult at best. I use the lathe method as often as I can using high RPM slow feed and clean out often. Nothing is guaranteed in life except death and taxes so think of where drilling end grain falls in the scheme of things.


-- See pictures on Flickr - And visit my Facebook page -

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