warped bit?

Signed-In Members Don't See This Ad
Status
Not open for further replies.

workinforwood

Member
Joined
Mar 1, 2007
Messages
8,173
Location
Eaton Rapids, Michigan, USA.
Maybe my 7mm brad bit is warped a bit at the end? Drilled a few acrylics and find the hole is sloppy at the top to about half way down, but close to the bottom it is sweet. That's not good, especially with a slim, because there isn't much meat left on the tube when a pen is finished so if there's a gap, it can be exposed or even blow out. I'll re-drill the tubes with a bigger bit and use them on a bigger kit, so they aren't gone, but am curious if ya'll think the bit when a bit warped at the end, or maybe something else is causing the problem? Visually looking at the bit spinning, it does kinda look like the end of the bit wobbles a teeny tiny bit, but kinda hard to say for sure. Tried laying it on a flat surface and rolling it to see, but that's a tough test too, because there are small burrs on the shank of the bit caused by the chuck jaws no doubt.
 
Signed-In Members Don't See This Ad

guts

Member
Joined
Aug 22, 2005
Messages
1,318
Location
Fairchance Pa. USA.
Jeff,not sure about the bit but I have noticed on some of mine that after I start the hole and bring the bit back out,when I start back down with the bit sometimes I can see it move as it enters the hole again,if it does then I adjust my vice a bit and no woller or very little at the top of the hole,hope this makes since to you.
 

gerryr

Member
Joined
Sep 22, 2005
Messages
5,353
Location
Billings, MT, USA.
I found this out the hard way. If a bit gets too hot, it will deform and once it does, toss it and get a new one. I had this happen with 8mm Euros and finally bought a new bit, sharpened it before the first use and everything was fine. The smaller the bit, the easier it seems to be to overheat.
 

Paul in OKC

Member
Joined
Jul 26, 2004
Messages
3,089
Location
Oklahoma City, OK, USA.
If your bit was warped, it would be sloppy all the way through. I find that this issue is more caused by the bit wandering just a tad when started. It causes a slightly oval hole at the top, but good at the end where the bit comes out. An extra step, but has anyone thought of using a center drill to start their holes? They are short and stout, and won't deflect (unless your quill has some play in it, which is another cause for the above issue). Use a #5, it will be large enough to cover most bit sizes (up to 7/16) A #6 is 1/2" diameter. These are used for starting holes in metal so the bit doesn't wonder, don't see why it wouldn't do the same for wood. Should be able to find them at Little Machine Shop, definately at Enco or MSC. Try a local industrial supply if you have one.
 

Woodlvr

Member
Joined
Feb 2, 2006
Messages
3,086
Location
Midvale, Ut,
Gerry,
Do you sharpen all of your bits before you use them? I had thought about it and wondered if it would ruin the factory sharpened edge. (if it has one)[:D]

Mike
 

wdcav1952

Activities Manager Emeritus
Joined
Mar 18, 2004
Messages
8,955
Location
Montgomery, Pennsylvania, USA.
Not to hijack the topic, put Paul mentioned quill play. My drill press has a tiny bit of quill play, but doesn't seem to deform the hole enough to notice. Paul, what is a good way to eliminate quill play?

TIA,
 

gerryr

Member
Joined
Sep 22, 2005
Messages
5,353
Location
Billings, MT, USA.
I sharpen every bit before I use it the first time. I've purchased too many that were dull right out of the package.

William, you'll go blind if your quill has any play in it.[:D][}:)][:D][}:)][:D][:0]
 

mikemac

Member
Joined
Sep 4, 2006
Messages
269
Location
Ottawa, Ontario, Canada.
You might want to check that the bit is perfectly centered in the chuck... i know I usually just put my bit in, and tighten it up with the key in one spot, but if I bother to check, I can sometime find that tightening in all 3 spots reveals that they weren't all the same 'tightness'(for want of a better term)[:D]
 

mick

Member
Joined
Mar 13, 2005
Messages
2,608
Location
Decatur AL, USA
This is all based on drilling on the lathe but I've noticed this with certain of the "plastics" we turn. I've tried to pay close attention each time it happens and here's my thoughts.
It happens to me more with any of the blanks that CSUSA calls "celluloids" i.e. Crimson Marble, Amber Marble etc..... and most of the Fleck blanks from AS. I've never had it happen with any PR blanks either ones I'm bought or made myself. I've determined that the more "rubbery" the blank is the more likely I am to have this happen. I've Started paying close attention as I'm drilling and have found out as the drill bit gets deeper into the blank the scrap material won't work out of the flutes of the bit because its sticking together from heat generated by the drilling. Sharper bits don't seem to stop the heat in this type material. If you don't back the bit out and clear the flutes often enough this material will start to force itself out of the flutes and will cause the blank to rotate in an eccentric rotation as the material "rolls" over between the blank wall and the bit. As this happens the portion of the blank already drilled will dig in to the cutting edges of the flutes enlarging the hole. This is why the sloppy part of the hole is always from the end you started drilling to close to halfway in. This is in no way a proven fact, just something I've observed and tried to figure out. Anybody have any better evplaination I'd be more than happy to hear it and will gracefully sit corrected....[:D]

On another note depending on what style of pen I'm making I fix this problem by gluing with thick Ca, centering the tube as near to the center of the larger portion of the hole as possible and filling in with more thick CA while standing the blank on end. If the pen wall isn't too thin, again depending on style of pen, you'll never notice the hole was larger than needed!

One more thing, when drilling longer blanks such as perfume pens I've started drilling from what will be the base, or larger part of the pen. That way if theis does happen you can easily use the CA fix and never know it happened.
 

Paul in OKC

Member
Joined
Jul 26, 2004
Messages
3,089
Location
Oklahoma City, OK, USA.
Originally posted by wdcav1952
<br />Not to hijack the topic, put Paul mentioned quill play. My drill press has a tiny bit of quill play, but doesn't seem to deform the hole enough to notice. Paul, what is a good way to eliminate quill play?

TIA,
Nor sure if you can. Most have a little set screw on one side, but that will only help one way.
 

Fred

Member
Joined
Feb 18, 2007
Messages
3,557
Location
N.E. Atlanta, Georgia U.S.A.
You mention that the bit has small raised areas on the side of the bit from tightening in the drill press. If you mount the bit and one of these is burrs is in the way that could throw the bit out of alignment. Reverse the bit and using a file, re-round the mounting end. I might suggest doing this on the lath with the bit all the way into a chuck, that way you don't stand too much of a chance in bending the bit if you get overly aggressive in filing the burrs off.

Many bits feel sharp but they seem to cut better for me if they are re-sharpened prior to use. A Drill Doctor is an excellent investment, but only if one takes the time to use if often. Check for them on sale at Sears or e-Bay. [:)]
 

workinforwood

Member
Joined
Mar 1, 2007
Messages
8,173
Location
Eaton Rapids, Michigan, USA.
Lots of interesting thoughts, thank you. I'm buying a new bit tomorrow. In the mean time, I drilled 7/64 or something like that, which is a fraction smaller than 7mm, then redrilled with 7mm. Still a bit of looseness in the first half of the acrylics, but not so much that they are unusable. Drilled some corian and some wood with the 7mm bit and the holes are absolutely perfect. So maybe it's not so much the bit as the material, but I'll grab a new bit anyhow. Sanded the bottom of the vise too, as it seemed to wobble a bit side to side like the wood on the bottom was warping. Must be china wood [;)]
 

ed4copies

Local Chapter Manager
Joined
Mar 25, 2005
Messages
24,523
Location
Racine, WI, USA.
I'm amazed no one has said this, especially Mick, who has "Nailed" the problem.

Put cool water in the hole. Drill about half an inch, empty and fill with cool water again.

Problem solved.

They don't call me the "resinator" for nothin!!!! (Well, Chris calls me that, anywho!!!)

Try it, it works!!! (Use your old bit, the new one will do the same thing.)[:D][:D][:D]
 

workinforwood

Member
Joined
Mar 1, 2007
Messages
8,173
Location
Eaton Rapids, Michigan, USA.
Sounds interesting, so I'll sure give that a try. I know your so right on the new bit Ed! I just got home and tried the new bit, same results. Only happens on acrylics and only certain ones too, as some of the acrylics drill perfect. Happy to hear about the water...thank Mick and Mr Resonator.
 
Status
Not open for further replies.
Top Bottom