Drill bit sizing question

[dweir]

I bought a "woodworker/artist" pencil kit from Woodcraft the other day so that I could make a lead holder for my daughter. She is only 12, but has become quite an artist and is into sketching. I thought this would be a nice addition to her artist tools. Problem is, that the kit calls for a 29/64 drill bit. The closest thing I have is a 15/32 which is a tad oversize according to the drill bit charts posted here. I would hate to spend $ on a bit that I will only use 1-2 times. If I go oversize, any tips to fill the gap between barrel/tube and wood. I have polyurethane glue and 5 min epoxy that may fill the gap. Or, should I go a little undersize and pound it in with a 8lb sledgehammer?

Thanks,
Dave

 

[Woodlvr]

You could go oversize and use the poly glue since it expands. The Drill bit chart shows only a .157 difference, do you have a 11.5 mm, it is only .0003 smaller than the 29/64ths. Good luck.

Mike

 

[dweir]

I think I might have an 11.5mm bit, I will look and see. Thanks for the help. If I don't have one, I will go with Poly glue.
Dave

 

[dweir]

Nope, no 11.5mm bit, all of my bits are SAE/Fractional (except for 7mm slimline bit), So, I will try the polyurethane glue.

Thanks,
Dave

 

[Aderhammer]

Make the investment, who knows maybe someone will want to buy some off of you? It is a very nice kit and very well constructed. I made one for myself for sketching in engineering class.

 

[Rifleman1776]

I make mine with a 15/32" which seems to be the perfect size.
BTW, your daughter will like. I have sold a number of these but offer them as either shop pencils or artists pencils. With hard lead they are for the shop, with soft, sketching. I'm about to make one for my grandson. Suggest, you turn B to B, they are fat already, with bulgies, might be too big for a small child.

 

[mrcook4570]

Originally posted by dweir
Or, should I go a little undersize and pound it in with a 8lb sledgehammer?

Never take this approach. It will put a lot of stress on the blank which could lead to cracking once the blank is turned (i.e. wood is too thin to overcome the stress from the tube).

I use 15/32" drill for these. I also use either epoxy or gorilla glue for gluing all tubes.

 

[ironhorse]

Great,
Thanks a lot. Something else I have to make now.

 

[dweir]

Wow! You guys are great. I tried the 15/32 bit in some scrap and it fits pretty decent. I scuffed the tube with 100 grit and it fits even better. I am waiting on some blanks to come in this week and I think Gorilla glue will hold it in.
My daughter is only 12, but she is almost 5'6" and her hands are almost "adult" sized, so I don't think she will have trouble holding the pencil/lead holder. I bought a bunch of 2/HB leads and I think she will be happy. I studied Engineering and Architectural drafting (pre auto-cad) and would have "died" to have a lead holder like this one.

I did not think about the "pound it in" theory, but it makes sense, especially with a thinner pen/pencil like a slim. I have had problems with lacewood blowing apart on slims..

Thank You all for the advice.
Dave

 

[Tea Clipper]

For only $40, you could get this 115pc drill bit set from Harbor Freight and have just about every drill bit you'd ever need!

 

[Randy_]

Other thing you could do is drill it undersize (7/16") and then sand it out. You could take a 1/4" dowel and cut a fine slot about 1" deep in the end of the dowel with a scroll saw or a coping saw. Then take take a small piece of sandpaper (220 grit maybe) and slip one end in the slot. Then chuck your dowel in an electric drill and open up the hole in the blank as needed. If you don't have enough clearance in the hole, you could try this alternative which I have used to enlarge bushings that are too tight on a mandrel. Cut the head off a good sizes nail and use a piece of duck tape to attach one end of a 1/2" x 2"± piece of sandpaper to one end of the nail. You need pay attention to the orientation of the SP so it will tend to wind onto the nail with rough side out when the drill is turning. Then chuck the nail in the drill and sand the inside of the hole. The SP will tend to clog up pretty fast so you will need to tear a little bit off the free end of the SP every so often to keep it cutting.

As far as I am concerned, this is an emergency, one time kind of solution. I second the earlier suggestion of purchasing the big set of HF drill bits. If you continue with this craft for any length of time, sooner or later you will need many of those drill bits anyway so buying bits individually or finding work-arounds is not the best way to go.

 

[n7blw]

Be very careful when drilling your blank with this large (29/64) bit. I managed to blow up two nice blanks while using the bit I got from CSUSA in a one-pass attempt. It is a spur bit without side shearing spurs, so doesn't cut well in dense wood. In the future, I'll probably drill the hole first with a very sharp 27/64 (Sierra size)spur bit I have that does have side spurs, then ream the hole to size with the 29/64 bit.

I have the big HF drill set. The bits need to be reground out of the box, and need to have a split-point grind added. Fortunately, I have a Drill Doctor that will do split points. The very small tip created by the split point minimizes wander in the wood.

 

[Rifleman1776]

n7, I don't know what a "spur bit" is. I know standard twist, twist with split points, brad points, spoon, spade, auger and probably a few others. But "spur" is a different hoss to me. Please explain.

 

[Randy_]

Maybe he is talking about a brad-point bit???

 

[Rifleman1776]

Originally posted by Randy_

Maybe he is talking about a brad-point bit???

At least I'm not alone in not knowing what he is referring to.

 

[Randy_]

YeaH; BUT YOU ARE IN BAD COMPANY!!

 

[dweir]

I have one of those 300 pc bit sets, but for some reason it has all sizes of bits below 7/16". The bits are of pretty decent quality with Titanium nitride/black oxide and brad points. Has a bunch of useless bits too. I will look into the HF bit set (I have a drill doctor) to dress them up.

I will try Randy's suggestion to sand out the hole on a scrap piece. If not, if I scuff the tube with 80 grit and use Gorilla glue, the 15/32 is just a hair sloppy and I can go with that also. I tested the 15/32 in a scrap of walnut.

Thanks again. If it comes out decent, I will post a pic.

Dave

 

[n7blw]

Sorry for the confusing terminology, folks. I DID mean a brad point bit.

 

[Rifleman1776]

Originally posted by n7blw

Sorry for the confusing terminology, folks. I DID mean a brad point bit.

OK, so now, we can debate with you, at least, semi-inteligently. []
You said, in part, "..a spur bit without side shearing spurs..."
Again, I'm kinda lost, 'side shearing spurs'? A brad point is a brad point. Right/wrong?
Dunno what you had there but, for you, it obviously didn't work. For me, I find brad points the ideal style for drilling end grain. They are my preference.

 

[Randy_]

Frank: Again I think (and that could be dangerous) that he may be comparing to Forstner bits that have the little "wing" (I don't know the technical term) that scores the outer diameter of the drilled hole.

 

[Daniel]

Brad points are designed for cutting clean holes in wood, reduce wondering. and cut from the outer edge of the bit toward the center. this tends to make them work better on end grain preventing the bit from following the grain, as well as reducing the outward pressure the bit exerts on the blank. where I have problems with them is exiting. they are more prone to blowing out the bottom of the blank. of course it is wise to use backing boards any time you drill to solve that problem.