Drill Press Drift Problems

[Tony Gardner]

Hi Everyone.

I'm working on a little project that will require threading together ten 1/4" x 1-1/2" x 12" New Zealand pine boards to form a flexible shelf. Since I'm using natural hemp string, I need to literally drill 1/16" holes all the way through the 1-1/2" boards. That gives me just about 3/32" of clearance on either side, so precision is really important.

I don't have a top-of-the-line drill press; it's a Wen 4214 with the Wen Drill Press Table attached. I have confirmed using the 135 degree bent rod sweep technique (actually, I found it best to use a Staedtler compass with a piece of paper on the DP table). In terms of calibration, I think my biggest problem is the angular "play" which appears to be increased significantly when using a 1/16" bit. To be specific, if I chuck a 1/2" steel rod, I get right around 0.004" of play, but with the 1/16" bit, it increases by 3x to 0.012.

To guarantee right-angle, I created a simple jig using two machined steel right-angles held together by M5 machine screws, and mounted to a flat piece of 3/4" MDF to reduce tearout. I then use an Incra Rules to poke tiny holes dead center and 1/2" in on both sides of the board. When drilling, I go half-way through on one side and half-way on the other, then test my success using a straightened-out jumbo paper clip.

Even with all my best care for accuracy, I still only have a 50/50 chance of having the two holes meet. For the ones that don't create a through hole, if I pick a side and drill all the way through, the bit will come out off center or worse on the corner edge.

At this point, I'm really considering a higher end DP, but since I only do woodworking as a hobby, it just doesn't make sense for me to spend big $$$ to solve this before I know what's really wrong.

Any insights from the SC community would be greatly appreciated.

Tony Gardner
Ruckersville, VA

[David M Peters]

Out of the box idea: how about forming your shelves from two thin boards sandwiched together, with one of the boards having a groove routed down its center? If you resaw from a thicker piece the cut line won't be horribly noticeable.

[Tony Gardner]

Thanks for jumping in, David. Believe it or not, that was the original idea that I pitched to my Dad, but he was very specific about the design, and I really thought I could pull it off!

All things being equal, alternative ideas are always appreciated, but I would prefer to learn about improving the accuracy of my drill press. Drilling a 1/16" hole laterally through a 1/4" x 1-1/2" board will definitely put your DP to the test!

[Dan Hahr]

It's not the play in the quill, it's the tendency for the bit to wander and bend as it encounters more or less dense grain. There may be a highly accurate drill bit out there that can pull this off, but I don't know where to find it.

Dan

[Andrew Seemann]

I haven't worked with New Zealand pine before, but I know that in other species of pine, the growth rings can be hard enough to deflect drill bits. And I am referring to bits larger than 1/16. Your best chance might be to do it in with one hole all the way through with a slightly larger bit. Even a 5/64 bit would help. I know that isn't your design, but it is possible that the current design may not work with the materials and constraints.

Either way, you will need to have the bit turning fast and back it out to clear chips often.

[Bert McMahan]

You will get less drift with less bit protruding from the chuck as well as a smaller number of flutes.

Something like this:

https://www.mcmaster.com/3146a112

may help as it has only 0.5" or so of flutes. You'll have to drill in and back it off repeatedly, but it'll deflect less since there is more metal there.

[Charles Lent]

I've never had great success drilling straight holes in tall lamps either. About the best that I could ever do was using a lathe and a gun drilling technique, but the wood grain throws that off too. My best success was ripping the wood down the center on my table saw, routing a half round slot in each piece, and then gluing the piece back together. To clear glue squeeze out and make the hole perfectly round I then ran a long drill bit down through the hole, which stayed well centered in the existing hole, leaving a nice round and well centered hole the full length. It takes some time to do all of this for just a round hole, but it's the only way that I've been able to do it and get good repeatable results. Keeping the two pieces of wood oriented so they got back together in the same orientation makes the glued back together saw cut almost invisible. All you loose is the width of the kerf.

Charley

[Tony Gardner]

Either way, you will need to have the bit turning fast and back it out to clear chips often.
Thanks for posting this, Andrew. My Wen manual specifies recommended speeds for various materials and bit thicknesses, but I can only guess what would be correct for a 1/16" bit into pine.

Are you aware of a more detailed reference I can refer to?

P.S. New Zealand pine is also know as "Select" pine, commonly found at Lowe's. At least, the sticker says it came from NZ!

[Tony Gardner]

What do you think of the idea of using a left-hand threaded bit? It would be a lot slower, but at least not as eager to gobble up every variation in the grain.

[Richard Coers]

For increased accuracy with tiny bits, you have to do a lot of peck drilling. Drill less than an 1/8" and then remove the drill and clear the flutes. Over and over and over. Really high rpm, and super slow feed. Having a steel drill bushing located in a fixture just above the wood can help guide it. Short of using a laser cutter, drilling a 1/16" to that depth would be difficult in any material, nearly impossible in wood.

[Derek Cohen]

Hi Everyone.

I'm working on a little project that will require threading together ten 1/4" x 1-1/2" x 12" New Zealand pine boards to form a flexible shelf. Since I'm using natural hemp string, I need to literally drill 1/16" holes all the way through the 1-1/2" boards. That gives me just about 3/32" of clearance on either side, so precision is really important.

I don't have a top-of-the-line drill press; it's a Wen 4214 with the Wen Drill Press Table attached. I have confirmed using the 135 degree bent rod sweep technique (actually, I found it best to use a Staedtler compass with a piece of paper on the DP table). In terms of calibration, I think my biggest problem is the angular "play" which appears to be increased significantly when using a 1/16" bit. To be specific, if I chuck a 1/2" steel rod, I get right around 0.004" of play, but with the 1/16" bit, it increases by 3x to 0.012.

To guarantee right-angle, I created a simple jig using two machined steel right-angles held together by M5 machine screws, and mounted to a flat piece of 3/4" MDF to reduce tearout. I then use an Incra Rules to poke tiny holes dead center and 1/2" in on both sides of the board. When drilling, I go half-way through on one side and half-way on the other, then test my success using a straightened-out jumbo paper clip.

Even with all my best care for accuracy, I still only have a 50/50 chance of having the two holes meet. For the ones that don't create a through hole, if I pick a side and drill all the way through, the bit will come out off center or worse on the corner edge.

At this point, I'm really considering a higher end DP, but since I only do woodworking as a hobby, it just doesn't make sense for me to spend big $$$ to solve this before I know what's really wrong.

Any insights from the SC community would be greatly appreciated.

Tony Gardner
Ruckersville, VA

Hi Tony

The way I would tackle this would be to drill from both sides of the board, meeting in the centre. This makes double the amount of drilling, but you would be assured of "accuracy" at each side. Also, deflection is increased when the bit loads up, so go slowly, and lift/clean the bit every couple of seconds.

Regards from Perth

Derek

[Bill Dufour]

I would drill from both sides about 1/4 of the way in. Then switch to a gun drill. I do not think you have near enough room for a supplied air blast down the drill. With then gun drill you will have to peck and clear the chips about every 1/2 diameter. You can probably make you own gun drill in that small size. I have a feeling NZ pine is just Monterey pine.
Interesting that Monterey pine has a very small natural area that it lives in but it has spread worldwide. All the natural groves are within 100 miles of each other.

[Andrew Seemann]

Thanks for posting this, Andrew. My Wen manual specifies recommended speeds for various materials and bit thicknesses, but I can only guess what would be correct for a 1/16" bit into pine.

Are you aware of a more detailed reference I can refer to?

P.S. New Zealand pine is also know as "Select" pine, commonly found at Lowe's. At least, the sticker says it came from NZ!


Even if I had a published reference, I don't think it would be useful. Most of those speed guides are for metals & plastics, i.e. materials that are uniform in density, hardness, rake angle requirement, etc. They aren't particularly useful for a material like wood, which can vary significantly just in the same board, let alone different species. Even by changing the angle of the hole relative to the grain (perpendicular vs parallel vs angled) will affect things.

In theory, you would pick the fastest speed on your drill press, because a 1/16 bit is about as small a bit as you would use, and wood is a soft material. That said, I suspect it would be too fast, probably much too fast. Heat disbursement would probably be an issue as well as chip clearance and the combination of those with the resin could seize the bit and break it.

I'd say put on a pair of safety glasses (important!) and start with the middle speed of your drill press and see how it does, assuming you haven't set it that fast. If it gives you the willies, or starts to burn, try a speed slower. If it seems fine and you feel brave enough, go a speed faster. At some point you will burn the wood, break the bit, or be too terrified to use the drill press. That will be one or two speeds too fast.

[Andrew Seemann]

What do you think of the idea of using a left-hand threaded bit? It would be a lot slower, but at least not as eager to gobble up every variation in the grain.

Not sure, but my guess is it would just burn or break. You could try it by putting a regular bit in your cordless and running it backwards. Even if it drilled, it seems that it would want to push the chips into the wood, rather than eject them.

[Keith Westfall]

I would think that a brad point would help a lot. Normal drill will tend to wander...

[Kevin Beitz]

Carbide bit and high speed...

[glenn bradley]

A couple folks are heading the direction I would go. A brad point bit of unquestionable quality; HSS, lipped geometry and choked up in the chuck to start the hole on one end, finish from the other side. That way the entrance and ext are dead-on even if the meeting point wanders a bit.

An auxiliary table for your DP built out of scrap for the purpose will help as well. Something to allow you to clamp in close. Not just like these but, these will give you the idea.

400905400906

[Tony Gardner]

SUCCESS!

Thanks to everyone who helped with this post. In my case, the best solution was to
1. Use the TiN 1/16" bit that came with my impact driver set (smallest flute)
2. Place the bit half-way into the chuck
3. Increase speed of DP to 1,7500 (originally at 1,000)
4. Use pecking method with frequent removal of sawdust.
5. Repeat on opposite side (due to reduced bit length).

Success rate is now at least 90%, and even better if I have my wife watch from the side.

[John K Jordan]

...I need to literally drill 1/16" holes all the way through the 1-1/2" boards.

Those are very "deep" holes for that diameter bit. My experience with drilling deep holes on the lathe is that if the drill is straight for some distance it will tend to drill straight the rest of the way. I always start holes with a center bit, but even the smallest would leave a chamfer on the surface.

Eliminating the flex at the start can help a lot. Sometimes I'll "choke up" on a bit so a smaller length extends out of the chuck. A 1/16" drill guide carefully made from metal might help a lot.

I'm wondering how you can precisely mark and start the center on the back with even the Incra rule. I'd probably try to rig up a pin indexing method. It's been a 1/2 century since I used one but in the Berea collage college wood industry shop I used a type of pin router with a single fixed pin coming up from the table and the router bit above. This was used with a template to make dished depressions for marble games, but seems one could be devised to precisely align the start of the hole on one side with that drilled on the other side. Mount a short pin to on a base to extend about 1/8" or so vertically aligned with the bit in the drill press. Position the work with a hole on the pin and then drill.

JKJ

[Gary Ragatz]

Even if I had a published reference, I don't think it would be useful. Most of those speed guides are for metals & plastics, i.e. materials that are uniform in density, hardness, rake angle requirement, etc. They aren't particularly useful for a material like wood, which can vary significantly just in the same board, let alone different species. Even by changing the angle of the hole relative to the grain (perpendicular vs parallel vs angled) will affect things.

Here's a DP speed chart from Wood Magazine that includes a variety of materials (including hardwood and softwood) and cutting tool types. I keep a laminated copy near the drill press.

https://www.woodmagazine.com/content/drill-press-speed-chart

[Dan Hahr]

It looks like you can buy end mills and solid carbide bits for routers or 1/8" collets. A lot of them are short in cutting depth. Maybe you could make a jig to start two very accurate holes from each side and then finish them with a longer bit.

Thanks, Dan