Drilling on the lathe question

[jleiwig]

So my PSI collet chuck arrived yesterday and I just now had a chance to take it out and look at it, and I ran into a couple questions.

On bigger pens like the baron and such that have different diameter holes, can I drill all the way through with one drill size, then cut the blank into the pieces I want, and then drill out the second piece? It shouldn't matter should it? Since the collet chuck is what centers the piece?

 

[TomW]

Should work. I would prefer cutting the blank first, since stopping, clearing the bit, restarting, stopping, clearing the bit, etc, etc,etc. aint my favorite activity, and 2 shorter blanks lessen that task....but that's just me.

Oh, and drilling the entire blank would require longer drill bit than I own...

Tom

 

[John M]

i cut them too. I dont have enough travel in my tail stock to drill some pens, like the click pen. I have to start it, get most the way through, then loosen the tail stock and push the rest of the way. You would have better luck cutting them since you would have less hanging out the the chuck so they should be more true.

 

[Rick_G]

I cut them as well. Drill bits long enough to do the whole pen in one shot tend to be more expensive and will be more prone to wobble producing a whole that is not exactly what you want.

 

[ldb2000]

I cut most of my blanks to size first then drill them on the lathe .

 

[jkeithrussell]

I have the same collet chuck set. Overall, it works great, but when you are drilling, stop every now and then and re-tighten the collet. It will work loose while you are drilling. If you don't tighten it up, the collet/blank will start to wobble.

 

[Jordan303]

Dont want to hijack the thread...but also dont want to start a new thread. I just started drilling and I prefer to cut the blanks first and i don;t have a power saw so I use a hand saw and just mount the wood in the chuck. Works way better then the miter box they gave me (im talking bout the psi 24TPI hand saw and miterbox).

ANyways when I drill let's say I use a 7mm drill bit for slimline pens. The tubes always have extra room to play...should I use a 6mm bit? What can I be doing wrong?

 

[Randy_]

For those of you that have the PSI chuck, does it have the same self-extracting feature as the Beall that requires the special technique for seating the collet in the chuck or do you just stick the collet in the chuck and screw the collar on??

 

[ldb2000]

You stick the collet in the collar then thread the whole thing on the chuck . It is self extracting but only with the PSI collets that come with it the ones from 800watt are just a hair smaller . If you tighten very tight the collet stays in the chuck .

 

[Randy_]

Thanks for the info, Butch.

I haven't ever looked up the specs for an ER32 collet and measured them to see how they match up; but an alternative possibility is that the PSI chuck is just a hair over spec. Since my collets from 800watt work just fine in the Beall collet chuck, I'm inclined to think the problem might be with the PSI chuck or maybe you got some undersized collets from 800watt?? I don't recall ever seeing another comment about the 800watt collets not working on the PSI chuck.

It would be interesting to know where the problem lies!!

 

[Rifleman1776]

For those of you that have the PSI chuck, does it have the same self-extracting feature as the Beall that requires the special technique for seating the collet in the chuck or do you just stick the collet in the chuck and screw the collar on??

I have two PSI chucks and am not familiar with what you mean by "self extracting".

 

[jleiwig]

I have two PSI chucks and am not familiar with what you mean by "self extracting".

The er32 collets are designed so that when pressure is relieved they expand slightly and should slightly "pop" out of the bore due to the angle of the collet being greater than the angle of the bore. In reality it does not happen very well even on high end production machines.

 

[VisExp]

Justin, I think you would be better off cutting the blanks first for the same reasons that others have mentioned. You will find the drilling to be more accurate. I round the blanks to 3/4", then cut them and then drill them.

 

[Randy_]

I have two PSI chucks and am not familiar with what you mean by "self extracting".

Frank: What I was referring to is the design feature that allows the chuck collar to engage the grove cut in the collet and pull it out of the chuck body as the collar is unscrewed. "Self-extracting" may not be the correct technical term; but it was the only thing I could think of when I made the post.

 

[KenV]

It is a trade off between process and precision. Your chances of an error in drilling goes up with the length you drill as you introduce more opportunity for Murphy Effect.

It also depends on how big a hole in what kind of medium --

A creative pen turner named "Eagle" provided a couple true sayings to the craft before he left us. One of them -- "the objective is to drill the center of the patten" to which I add - that the center of the pattern is not necessarily the center of the blank. Often I find the center of the pattern is not the center of the block of material I am working with.

Better precision and repeatability will be to center patterns on shorter pieces and drill less length. Machinists will use a short stiff center bit to start the hole and then drill successivly larger holes to minimize drift. To a machinist, drilling is an approximation, not a high precision operation.

So depends for me on what I am doing -- a piece of FOG (found on ground) wood or a piece of glue and pieces that I have spent hourse assembling.

 

[jleiwig]

Thanks everyone. I was just looking at different ways in case I were to blow through the end of a blank when drilling.

 

[TomW]

in case I were to blow through the end of a blank when drilling.

Just to be clear, when I cut my blanks into 2 before drilling, I don't size the blanks for the tubes, just divide the blank, leaving each as long as possible. Generally leaves 1/4-1/2 inch oversize, which is insurance for blowout. I don't size the blank until the tube in in place.

Tom

 

[jleiwig]

Just to be clear, when I cut my blanks into 2 before drilling, I don't size the blanks for the tubes, just divide the blank, leaving each as long as possible. Generally leaves 1/4-1/2 inch oversize, which is insurance for blowout. I don't size the blank until the tube in in place.

Tom

Which seems to me to be double the work, hence why I asked if it was ok to drill a starter hole through the blank first. I don't plan on blowing out a blank, but accidents do happen.

 

[KenV]

Justin -- what you propose will work, it will not work as well on some situations.

It will probably be fine on most 2 piece pens, but may not give the desired control on other situations.

As a rule of thumb -- process shortcuts are generally done at a loss of degree of control over variability and sources of past problems. Key is to be variable in your processes, so that you have protocols when it matters.

I would not use that long drilling process when I wanted to be dead on sure of nailing the center of the pattern on a checkerboarded glueup pen blank. Drifting off pattern by a few hundredths of an inch is visible. I will cut in the middle and make every effort to nail both ends, drilling from the middle of the blank in both pieces to make maximum effort to get matched pattern where it counts. With a capped pen, I match the nib end with the threaded end if the cap and go for making the patterns flow.

The trap is to have one "magic process" as you have multiple objectives and compromises that can fail in important situations. "Oh Scut" situations.

 

[jkeithrussell]

Dont want to hijack the thread...but also dont want to start a new thread. I just started drilling and I prefer to cut the blanks first and i don;t have a power saw so I use a hand saw and just mount the wood in the chuck. Works way better then the miter box they gave me (im talking bout the psi 24TPI hand saw and miterbox).


ANyways when I drill let's say I use a 7mm drill bit for slimline pens. The tubes always have extra room to play...should I use a 6mm bit? What can I be doing wrong?

Are you drilling on the lathe? You may have some wobble -- it sounds like you are getting some slop or wobble and the resulting hole is larger than the drill bit. A 7mm drill bit should give you a fairly snug fit with most 7mm tubes. There should only be enough extra room to allow for glue.