CHICAGOHANDS QUESTIONS

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CHICAGOHAND

CHICAGOHAND

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Joined
Apr 1, 2007
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361
Location
SUGAR GROVE, ILLINOIS, USA.
I am having a little to much slop between tube and acrylic while using my 7mm bit and after measuring the tube I was wondering if anyone is using an "H" or an "I" size drill bit?
The "H" bit measurs .266 while the "I" bit measures .272.
The tube size is .268 and a 7mm bit is .2756. I have tried a 17/64" bit which measures .2656 but that hole is just to tight.I have moved away from the 3/8 bit on the atlas pens Iam turning and have been using a "U" size bit which is .368 as opposed to the 3/8 bit which is .375.
The tube on the Atlas measures .365 and with the "U" bit I am getting a great fit.
I know this post is hard to follow but it is late and I am looking for any advice for a better fit.
I am turning between centers and that has helped out tremendously the out of roundness, but I still get a small ridge and I am trying to eleminate all possibilities.
I have noticed a huge improvement on the Atlas now the 7mm pen tubes are in my sights.
 
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Thanks for the tip. I've noticed some variances in some of the 7mm tubes, with a resulting loose fit. I'll experiment with some smaller bits. These are times when having a full 115-piece drill bit set comes in handy for those weirdo sizes.:D

Cheers.
 
I don't think that small ridge you say you are getting has anything to do with the size hole you drill. Once you glue the tube in it should stay put, ASSUMING it's really glued properly and not moving any. More than likely the problem lies with the fit between bushing and tube, IF you're using bushings. If you're mounting the blank straight to the centers without bushings than the problem could be the ends of the tubes not being perfectly square.
Another possibility could be the head and tailstock not lining up. Just because the points line up doesn't mean that the headstock or tailstock isn't
skewed a little. They need to be in a straight line with each other both horizontally and vertically.
 
Like Rick, I don't think the ridge is coming from the hole size. But I have tried an "I" bit on 7mm pens. In fact, it's what I use for casing pens. It is a pretty snug fit and I don't think it would give you a good glue joint through the length of the tube. An "H" bit would be too small and feel much like the 17/64" you tried. I can't remember the dia of the "J" bit, but I've been using it for 7mm pens sice my 7mm Brad point started wandering.
 
At one time (Don't know if it still is), Berea recommended the J bit for all 7 mm kits. Jim's philosophy was it allowed better glue adhesion.
 
On my chart here it tells me that a "J" bit is 7.04mm that would put me going the wrong way.
I am leaning towards the head and tail stock not lining up. I am just trying to eleminate any and all possibilities as to what is causing my problem, and the slop I have using the 7mm bit is unacceptable to me.
Now I am turning with bushings between centers which has reduced my problem alot.
Lining up the tail stock seems fairly easy as long as the live center and dead center are touching each other but the more I move the tail stock away from the head stock I could be drifting into never never land.
How do I go about checking that they are lined up once I move them apart ?
 
This is not the safest thing to do, (There, I have the disclaimer).

Set up the mandrel, but don't put blanks on it, make sure to seat it in the headstock. Now, turn on the lathe with the tailstock away from the end of the mandrel. Is the mandrel turning true? Not wobbling on the end? IF so, bring up tailstock slowly. Does it line up? IF not, put spacer on rail as required to make it line up, then lock in place (without hitting mandrel), does it still line up? When it does, you know what spacers you will need on which rail to make everything turn "round". If the mandrel is not turning true at the end, investigate your headstock.

Good Luck. (Mine needs the thickness of a piece of sanding cloth on the front rail - use it every night!!)
 
Maybe you need one really long dead center custom made?

That is the down side with the 930 series lathe is that there can be some play between the ways. However, as a wood lathe, this was not tool built to the spec's like a metal lathe. The percise tolerance we want for the pens would of come from metal lathes. I have thought at times of getting a fancy new VS mini lathe for pens and stuff. I just have a hard time paying that much for a tool. ;)
 
I hear ya there.
There might be a way to align this stuff with some brain power, here is some more stuff

http://www.mudhole.com/Shop-Our-Catalog/Renzetti-Laser-Guide-Alignment-Tool



http://www.easylaserusa.com/spindle.htm

this is for aligning fishing rod guides.
I think with some good old American inginuity ( i dont even know if that was spelled right) i might be able to inexpensively figure this alignment problem out.

A little duct tape a hand held laser and a mirror and some weird looking glasses I might finally be committed to an institution by the wife.
 
I just finished drilling 5 acrylic 7mm euro blanks with my new "I" size drill bit from "ENCO" and let me tell you the fit is great.
one problem I could have fixed is if I used the 7mm bit for this I should have probably slowed my drill press down a bit from my do everything speed of 3100 rpm.
But with my drill press at that speed and with an "I" size bit in it I have achieved the fit I was looking for. After I get done drilling I clean blank out by sliding blank up and down drill bit a few times.
The small ridge at the nib can be reduced if I could remember to place the nib bushing at the head stock instead of the tail stock. Some habits are hard to break. I am still getting a slight out of roundness which is noticable after I get close to final diameter and I rotate blank while keeping bushing stationary. I am trying to get in the habit of getting close to final diameter and then squaring blank up with my own makeshift barrel trimmer slash sander, an idea I came up with all by myself,
http://www.penturners.org/forum/topic.asp?TOPIC_ID=33091


"after seeing "Firefyter-emt" newest contraption".
 
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