Hole too large

Signed-In Members Don't See This Ad
Woodchipper

Woodchipper

Member
Joined
Mar 15, 2017
Messages
5,965
Location
Cleveland, TN
I have drilled several pieces of acrylic and had no trouble. This one pen is getting to me! I drilled it on the lathe, as the others, but the hole is larger on one end than the other. When I inserted the tube, there is a big gap on one end of the blank. I checked some other blanks on the workbench and they have a snug fit. Keep in mind this bit is short and must be withdrawn, the quill cranked down and reinserted to finish a 2-1/4 blank for a Slimline. Your help is appreciated. I think I quit drinking too early.
Looking at Fisch bits as the instructor at my grandson's pen class said they are longer and work great for longer blanks.
Edit- I checked the quill travel and it is only 2-1/8 inches. If I back it up any more to get an extra 1/4 inch, the Jacobs chuck comes out.
 
Last edited:
Signed-In Members Don't See This Ad
It sounds like you have movement of the drill bit. Maybe either the quill is loose or maybe the tailstock is loose? Just my first thoughts.
 
What lathe? Many small/inexpensive lathes do not have precisely ground/milled ways. The tail stock is not always coaxial and how close to coaxial it is varies.

I am not sure I understand your drilling procedure entirely. What do you mean the quill is cranked down then re-inserted?
 
Turn off lathe, Remove the bit, crank your tailstock back to starting depth, Turn blank around in the chuck, drill remaining half from the other end. While going back into the original hole, your either getting wobble, OR you are getting break out when the drill bit goes thru the far end. Just my guess. YMMV
 
you are getting break out
Click to expand...
The larger hole is where the bit enters the blank when I first start drilling. Lathe is Rikon 70-050VS.
I am not sure I understand your drilling procedure entirely. What do you mean the quill is cranked down then re-inserted?
Click to expand...
The travel of the quill is too short even for a 2-1/2 inch blank. I have to stop the lathe, move the tailstock forward while cranking the quill back, then start drilling again.
 
Last edited:
I have the Rikon 70-220VS and ran into the same issue every time I drilled. I'm convinced the quill wobbles sometimes in the tailstock. Not much, but enough that pens can be a problem or if I'm drilling to use a 7/8" or 1" IX collet. I snugged the allen screw on the front side of the tailstock down into the quill so it wouldn't move, then backed it off just enough for the quill to move smoothly. Whenever I drill, I tighten the quill lever down then back it off just enough that the quill will advance then start the hole very slowly. This helps out a lot, but I still get the bad hole from time to time.
 
I drill (bore) my blanks on my Shopsmith using a PSI pen blank chuck. Using the same drill bit and technique, with square blanks, I can have a centered hole one time, and the very next blank will be off center. Or vice versa. Can't figure it out, but suspect it its something I am doing.
 
Have you ever measured the blanks? Are they always perfectly square?

After I reach Max drilling. I shut off the lathe wait for it to stop, THEN back out the bit. Then I turn the blank atound, and finish drilling from the other end. That way I'm only going in each end once. I have a cheap HF lathe, so it wobbles if I loosen the tailstock to back out while it's turning.
 
Last edited:
TT, thanks. Will play around with it today. I have 10 pens for Christmas gifts. I looked at some of the blanks and they are perfect but can't remember if I drilled on the DP or lathe.
I have some 3/4x3/4 hardwood that I will experiment with and see what I can do.
 
BURLMAN said:
I drill (bore) my blanks on my Shopsmith using a PSI pen blank chuck. Using the same drill bit and technique, with square blanks, I can have a centered hole one time, and the very next blank will be off center. Or vice versa. Can't figure it out, but suspect it its something I am doing.
Click to expand...

I also use my Shopsmith and have found that if the blank is not perfectly square my drilled hole may not be exactly in the center of the blank.
I also mark the center of the blank to see if the drill chuck has moved. I wish the tail stock was deeper than it is so as to prevent some of the movement at the Morse taper.
 
The lathe is not aligned perfectly, probably nothing you can do to the lathe, I always make mine a little longer and insert the tube from the exit end and remove the excess blank from the entrance end.
 
Woodchipper said:
I have drilled several pieces of acrylic and had no trouble. This one pen is getting to me! I drilled it on the lathe, as the others, but the hole is larger on one end than the other. When I inserted the tube, there is a big gap on one end of the blank. I checked some other blanks on the workbench and they have a snug fit. Keep in mind this bit is short and must be withdrawn, the quill cranked down and reinserted to finish a 2-1/4 blank for a Slimline. Your help is appreciated. I think I quit drinking too early.
Looking at Fisch bits as the instructor at my grandson's pen class said they are longer and work great for longer blanks.
Edit- I checked the quill travel and it is only 2-1/8 inches. If I back it up any more to get an extra 1/4 inch, the Jacobs chuck comes out.
Click to expand...

I get the same thing on my damascus from time to time. it was from not clearing the bit enough. the shavings in the flutes act like sandpaper when jammed up. my solution was clear more as well as like ed says drill a pilot hole first. just my 2 cents worth.
 
The lathe is not aligned perfectly, probably nothing you can do to the lathe, I always make mine a little longer and insert the tube from the exit end and remove the excess blank from the entrance end.
Click to expand...
I would still have a big gap between the blank and the tube. I can see down in the blank and it would require a lot of CA to fill it. I'm thinking of going to Two Ton Epoxy that I used for installing fishing rod grips. It's thick and shouldn't run like thick CA.
 
Beautys_Beast said:
... After I reach Max drilling. I shut off the lathe wait for it to stop, THEN back out the bit. Then I turn the blank atound, and finish drilling from the other end. That way I'm only going in each end once. I have a cheap HF lathe, so it wobbles if I loosen the tailstock to back out while it's turning.
Click to expand...

What happens if the bit wanders or is off center when you begin drilling?

Artisan iron designs said:
I get the same thing on my damascus from time to time. it was from not clearing the bit enough. the shavings in the flutes act like sandpaper when jammed up. my solution was clear more as well as like ed says drill a pilot hole first. just my 2 cents worth.
Click to expand...

I've suspected this on a few of mine. Thanks for clearing it up.
 
gtriever said:
Beautys_Beast said:
... After I reach Max drilling. I shut off the lathe wait for it to stop, THEN back out the bit. Then I turn the blank atound, and finish drilling from the other end. That way I'm only going in each end once. I have a cheap HF lathe, so it wobbles if I loosen the tailstock to back out while it's turning.
Click to expand...

What happens if the bit wanders or is off center when you begin drilling?
Click to expand...

Then your having a bad day. Always start drilling SLOWLY. Although I may start taking Ed's idea, and drilling a pilot hole first.
 
Woodchipper, I just recently had that problem with the hole getting larger at the entrance site. It was for a seam ripper blank, my quill does not travel far enough to get the bit all the way through, I have a Jet 1014VS. I backed out the bit, moved the quill closer to get through the blank, re-inserted the bit and the hole was oversized.

I fixed this by when I need to move the quill towards the headstock to have enough travel to get through longer blanks I put the drill bit into the hole before starting the lathe and that fixed my problem. That way you won't have to turn the blank around, I have had problems when I did that.
So just try, for longer blanks, to start the lathe up after you move the quill further to get the extra drilling length and put the bit into the hole before starting up. It worked for me, maybe it will solve your problem, good luck.
Tim.
 
Last edited:
Tim, tried that too. I'm going to see if I can fine-tune my drill press for drilling.
I made sure all the screws and locking gadgets were tight or snug to prevent any play in the quill or tailstock. Same with the chuck and headstock.
 
Is the over size hole is on the bit entrance side of the blank? Stop the lathe or drill while withdrawing the drill bit, insert the drill bit into the hole before starting the lathe or drill.

Check drill bit for bends. Roll on the top of a flat surface (like a table saw) to detect bend drill bits. They can be bent even when new!
 
Last edited:
I do not max out the Quills travel, I only drill a short distance., back it up and push into the hole and restart. I do this all the time. It takes longer but it works in keeping hole straight.The further the quill is extended, the more movement/vibration there is. When you consider the length of the bit and the quill, well its pretty far out there. Good Luck, Carl
 
I recently drilled a large hole completely through some wood pen blanks.
The blanks were all about .750" to .797"and none of them were exactly square. The hole I drilled was a 43/64 (.672")reduced shank jobber drill bit. No smaller bit was used prior to the 43/64" bit.
Each time I tried to make sure the drill bit was drilling the center of the blank and I drill half way thru from each end. I marked the centers with a 3/32" drill bit about 1/8" deep before starting the process. I did 3 of them and they all had some degree of difference where the holes met in the middle. None of the split or blew apart. When I drilled them, I backed the bit out about 6 times on each end and I DID NOT start the lathe for the next plunge with the bit inside the blank.
Then, I tried another one but this time I ran a starter bit into the centers.
When I began the drilling, I made sure the blank was spinning centered by noting the starter bit hole. I made sure it was not wavering.
This time there is such a small difference where the holes met in the middle it is almost not noticeable.
If the blank is running true to center and the lathe is set with the axis of the chucks aligned, the blank should not even move from center when you start the next plunge. If there is a wobble or vibration, then something is not set correctly.
 
The problem is the lathe. A wood lathe isn't designed to maintain accuracy when loosening the tailstock and retightening it. There is discrepancies when doing this. The tailstock has enough play, that it will not tighten back into the same position without some extra precautions.

The only way to ensure a perfect hole, is to use a metal lathe using the auto-feed. First, chuck the blank and use a center drill. Then move the tailstock into position to support the end of the blank. Turn the blank round and then flip the blank end for end. Repeat the above steps on this end. Now the blank should be perfectly round from end to end. Back the blank into the chuck until only about an inch protrudes and using the center drill hole, drill the blank just past half of the length. Now flip the blank end for end and repeat. This should result in an almost perfect hole that is round and centered, assuming the tailstock isn't moved during the procedure and depending on the accuracy of the metal lathe. It will still be better than using a wood lathe.

This method is quite involved, but you only get out, what you're willing to put in.

I apologize for the lengthy response.
 
It's good practice to start the hole with either a centre drill or a spotting drill before continuing with a conventional drill bit. Centre and spotting drills are not expensive.
 
Oh, great. Now I have to tell SWMBO that I need a metal lathe?
I experimented on an acrylic blank. One part I drilled about halfway, stopped the lathe, backed the tailstock out, cleaned out all the fuzzies, inserted the bit, started the lathe and drilled the rest of the way. Very accurate with virtually no gap between the blank and the tube on either end.
The second one a bit different- I drilled and backed out the tailstock and reinserted it while running. This reamed the entrance so that I had to drip thin CA into the gap. Just finished the second filling of CA. Hope it comes out so I can turn it tomorrow and finish the pen.
 
Terredax said:
The problem is the lathe. A wood lathe isn't designed to maintain accuracy when loosening the tailstock and retightening it. There is discrepancies when doing this. The tailstock has enough play, that it will not tighten back into the same position without some extra precautions.



The only way to ensure a perfect hole, is to use a metal lathe using the auto-feed. First, chuck the blank and use a center drill. Then move the tailstock into position to support the end of the blank. Turn the blank round and then flip the blank end for end. Repeat the above steps on this end. Now the blank should be perfectly round from end to end. Back the blank into the chuck until only about an inch protrudes and using the center drill hole, drill the blank just past half of the length. Now flip the blank end for end and repeat. This should result in an almost perfect hole that is round and centered, assuming the tailstock isn't moved during the procedure and depending on the accuracy of the metal lathe. It will still be better than using a wood lathe.



This method is quite involved, but you only get out, what you're willing to put in.



I apologize for the lengthy response.
Click to expand...



If you use a dead center in your chuck, you can turn the blank round between centers and not have to reverse it. Quicker and more accurate. Added benefit is I can "trim" the ends on my sander using a simple fence 90 deg to the sand paper. The ID and OD are parallel.

Danny


Sent from my iPhone using Penturners.org mobile app
 
Dan, not real sure what you are calling a dead center for the chuck. Found some possibilities at WC but not sure.
I have come to the conclusion that filling the gap isn't going to work, like the last one, as the the blank will too thin for a Slim Line and the glue will show through. Arrrgggghhh!
 
Woodchipper said:
Dan, not real sure what you are calling a dead center for the chuck. Found some possibilities at WC but not sure.
I have come to the conclusion that filling the gap isn't going to work, like the last one, as the the blank will too thin for a Slim Line and the glue will show through. Arrrgggghhh!
Click to expand...

paint the inside of the blank, before gluing it up. I do this, just so I don't have that problem. Also, don't use CA glue, use epoxy. Epoxy will fill in the space easier.

Always test fit tubes, prior to gluing. Then if you have gaps, you can add epoxy to the blank first. If you get epoxy in the tube, just use a round file to clean it all out. I do it while barrel cutting, with the blank on the lathe, cleans it out in no time.

P.S. I have ZERO idea what I am doing most times, and am a VERY inexperienced turner, just trying to help, not tell you how to do it.
 
Last edited:
BB:
1. I always check the tube int he drilled blank.
2. As mentioned, the Slim Line blank turns down so the glue is highly visible. I had one where I actually turned all the acrylic away and had the glue left.
3. I used a file and the parts fit too loose from unknown reason.
Got some ideas for drilling. Ed Brown has a video on drilling- he orients the blank to the drill bit and then secures it in the vise. I have done this and it works. I found that many of the blanks aren't square and wobble in the pen chuck. Turning and then drilling, IMHO, takes too much time, especially considering the time it takes to turn acrylic as opposed to wood.
 
Woodchipper said:
TT, thanks. Will play around with it today. I have 10 pens for Christmas gifts. I looked at some of the blanks and they are perfect but can't remember if I drilled on the DP or lathe.
I have some 3/4x3/4 hardwood that I will experiment with and see what I can do.
Click to expand...


Since you have a drill press, that is the way to go using a pen blank chuck. A long (enough) drill bit will help also. Go slow. With time and experience you will learn how fast you can advance your drill for a clean hole. In my experience, using the lathe to drill the hole slows down your production time also. Downside to this is you will have to invest in a quality drill bit and blank chuck. But, with time they will pay for themselves.
 
More4dan said:
If you use a dead center in your chuck, you can turn the blank round between centers and not have to reverse it. Quicker and more accurate. Added benefit is I can "trim" the ends on my sander using a simple fence 90 deg to the sand paper. The ID and OD are parallel.

Danny


Sent from my iPhone using Penturners.org mobile app
Click to expand...


The issue with using a dead center in the chuck would be, the center has a Morse taper and can't be held square or concentric to the chuck. Therefore, a dead center with a straight shaft would have to be produced (I haven't found any to purchase) so, using the chuck is a simple solution. The hole is still very accurate with this method, since the blank will be turned concentric to the chuck and not a center, and eliminating another connection to create deflection.
Of course, the point is moot, if one doesn't have a metal lathe to begin with.
I have access to one via my neighbor.
 
Terredax said:
More4dan said:
If you use a dead center in your chuck, you can turn the blank round between centers and not have to reverse it. Quicker and more accurate. Added benefit is I can "trim" the ends on my sander using a simple fence 90 deg to the sand paper. The ID and OD are parallel.



Danny





Sent from my iPhone using Penturners.org mobile app
Click to expand...





The issue with using a dead center in the chuck would be, the center has a Morse taper and can't be held square or concentric to the chuck. Therefore, a dead center with a straight shaft would have to be produced (I haven't found any to purchase) so, using the chuck is a simple solution. The hole is still very accurate with this method, since the blank will be turned concentric to the chuck and not a center, and eliminating another connection to create deflection.

Of course, the point is moot, if one doesn't have a metal lathe to begin with.

I have access to one via my neighbor.
Click to expand...



With a metal lathe you can easily make a straight shaft dead center using 1/2" drill rod. Very useful for turning between centers too.


Sent from my iPhone using Penturners.org mobile app
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom