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Drilling again

John Torchick

John Torchick

Joined
Jan 24, 2010
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I was working on a wood reel seat for a custom fly rod. I had it all turned and finished. Next, I needed to make the ID a bit larger to slip on the blank. I used a hand reamer (fiberglass with coarse sandpaper) and thought it was too slow. I got impatient and drilled it freehand. When I trimmed the length, I found the bit had drifted and the hole was off center; more at the exit end. The hole is 3/8" and I can drill to 7/16 if needed. My question- if I put it back on the lathe, will the lathe bit drift, following the exising hole? I don't think so but am relying on those with a lot more experience than I have. Thanks.
 
I don't see much hope for fixing the problem by trying to ream the existing hole. There will always be some very small alignment error between the drill and chuck and the drill may not be perfectly straight.

Much more significant would be the misalignment of the spindle and tailstock centerlines. There will always be some radial and angular misalignment. Measuring and correcting the radial misalignment is not too difficult. Unfortunately, the same can't be said for angular misalignment.

While the drill itself may not drift significantly, the real problem is the wood deflecting from side loading forces so that the existing hole will try to follow the drill. If the wall thickness of the wood is thin, this is more likely to happen as well as resulting in the hole going out of round. Additionally, if the wall thickness of the hole is not substantial, chattering could cause the hole to become irregular.

I don't have a good suggestion for the type of drill to use, but make sure that it is a new sharp drill. Even slightly dull drills can exacerbate the type of problem that you encountered.
 
The drill bit will follow the off center hole. I suggest using a small hollowing tool to true up the hole before drilling bigger. Another trick would be to try a router bit in a chuck in the tailstock. Since the router bit is designed to cut on the side, it will actually true up the hole as you feed it in with the tailstock.
 
John Bill has laid it out perfectly. There are 2 major problems here that creep in. Angular alignment of the headstock and/or tailstock (depending on how you drill) and the fact that a standard drill will wander following the grain and will even wander in metal.
The way holes are typically bored accurately is to use a boring cutter that cuts from just one side instead of both. Woodturing places sell a bit called a Lamp Auger bit that does this.
http://www.highlandwoodworking.com/lampaugerbit38.aspx
I have one and it can still run out due I think mostly to flex in the shaft and maybe still some differences in the hardness of the wood. It is much more accurate for long hole drilling in wood.
You can make your own. I tried and it didn't seem to cut any better than my Lamp Auger.
http://books.google.com/books?id=1S...=0CD0Q6AEwAA#v=onepage&q=d bits drill&f=false
The short distance you are drilling a D bit might work. The ones in the article above aren't like the one I built. Mine only cut on one side so it was more like the action of metal working boring cutters and did pretty good. It didn't clear the chips very well so you had to remove the bit and blow them out with compressed air.
If you feel like driving up some afternoon we'll experiment and see how we can do.
You might be better off drilling from both ends. It still might be off in the center but the will be very close and a longer drill bit run completely through will then correct the problem. I've done that with lamps and it works pretty well.
 
I really hate to lose this piece of wood as it has a great grain! Looks like I'll have to go another route with another piece of wood. Fred, I feel that plugging and redrilling would be more trouble than what it's worth. Thanks for the suggestion. I'll play around with it and see what I can come up with. Thanks to all for the replies.
BTW, the wood is caragana (q.v.) and about 8 coats of Tru-oil Gunstock Finish. The finish really brings out the grain. Light isn't the best.
 

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John How long are these pieces. If they aren't too long I can probably fix the hole on my metal lathe. Then I could show you how it might be done on a wood lathe.
 
John,
A suggestion might be to drill and fit the blank at a rough turned stage or even square stock then
Finish turn between two cone or pin centers.

We used to turn lots of tiny bird house ornaments. Our fist step was drilling an 11/16 hole 1" deep. Then rough turn and finish turn on a wooden pin. The walls could be turned to 1/16 very easily.
Also the wooden pin had 1/16 step for a guide.

Also always more accurate and easier to drill holes first and then use the holes to center the work.
Pens and pepper ills are usually drilled first.

I also did some curtain pulls which I always drilled first.

Al
 
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Chuck up the old one, use a side scraper made out of an old spade bit.
 
It fit!

As usual, the timberturners come through. Again, I appreciate all the replies and the great information- will file it for future reference! To back up a bit, I turned the wood between centers and turned a tenon on one end. I put the tenon in a three jaw chuck and drilled to 5/16 (should have gone a bit bigger) and then put it on a 5/16 mandrel between the Jacobs chuck and live center. Turned to dimensions. But, as I said, I got impatient with hand reaming and drilled with the insert in one hand and the drill in the other. Duh! Doesn't work!! Put that on list of things-not-to-do. I fussed and fumed over it. Forum friends came to the rescue. I finally discovered I could use a hand lathe to ream to a good round shape and the ID I needed. Hand lathe, you ask? It's a wood rasp in the left hand and the insert in the right hand. I got the ends to the proper ID/wall thickness. Then I turned the insert with the right hand while operating the rasp in the other, using the parallel part to clean up the inside. When it looked good with the one-eye inspection tool, I put it on the rod blank. Eureka! It fit! I'll commit to posting pictures of the finished turned insert and turned custom grip. Again, thanks! BTW, the rod is for my grandson.
Hockenberry, thanks for that tip. I'm going to try and make some tree ornaments for the holidays. Need to get started.
My son can have some mandrels made from drill rod in various diameters. Shoulder on one end and drilled on the other end for the live center. This will make this much easier than lots of reaming.
 
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John Torchick said:
.... Hand lathe, you ask? It's a wood rasp in the left hand and the insert in the right hand....
Click to expand...

At work, we called that a Third World Milling Machine.

BTW, while not actually admitting to doing things the wrong way when in a hurry, I have learned lessons like this in a way that tends to stick with me more than just reading about what not to do. So, every dark cloud has a silver lining (at least, that's the story I hear).
 
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