Drilling Advice on Spectraply

[Daniel2025]

Hello group. I'm needing some advice. I've had excellent results using the PSI 12" Lathe with tailspinner. I beleive the centers line up Very well.
I'm using a 1/2" drill chuck and a pen blank holder that screws on the 1 x 8 threads. Using a brad point 7mm bit, it runs true. No wobble.
RPM's are lowest about 480. Moving very slow, backing out every 1/2" or so to remove the shavings, minimal heat build up. Works great except the exit hole is always off center. Not a real problem for thin pens. I've done these with drill bit in the headstock, and also in the tailspinner. No difference either way. I not getting in a hurry.
I've tried with rpms about 700 no change. Happens only with the spectraply, Not hardwoods or acrylics.
Perhaps this is just charactoristic of the multiply??

Thanks for any input

DAVE

 

[jttheclockman]

It is not with spectraply woods. They are firmly glue in place. I suggest trying a machine bit instead of the brad point bit. Make sure your bit is not bent. Make sure the headstock and tailstock are lined up straight.

 

[bugradx2]

Do you cut your blank prior to drilling it or drill into a "final length" blank? Could it be chipping out a little ?

 

[Daniel2025]

It is not with spectraply woods. They are firmly glue in place. I suggest trying a machine bit instead of the brad point bit. Make sure your bit is not bent. Make sure the headstock and tailstock are lined up straight.

When you say machine bit, is that another unique bit, or just your common everyday drill bit?

Thank you

Dave

 

[Daniel2025]

Do you cut your blank prior to drilling it or drill into a "final length" blank? Could it be chipping out a little ?

I always cut my blanks before drilling,

Thanks

Dave

 

[MRDucks2]

Two things that have contributed to this for me.
1- Brad point bits need to be extremely sharp to work well. I am talking cut your finger if you bump the flute sharp.

2- I find this one a bit embarrassing after I figured it out, but I was bottoming my blank in the pen jaws. In other words, the end of the blank was against the back of the jaws/face of the chuck. By ensuring I allowed the "jaws" to actually hold the blank with a gap at the back it really helped my hole alignment.

 

[jttheclockman]

When you say machine bit, is that another unique bit, or just your common everyday drill bit?

Thank you

Dave

Common drill bits. Does not matter the angle of the bit.

 

[bugradx2]

After re-reading this, you're saying the same setup and same bit do not have this issue with other woods, correct? I wonder how hard those wood types are vs spectraply.

Could your drill bit be off just a hair and therefore cause the non circular hole? Try swapping to a brand new bit and see if you get the same issue in your spectraply.

I've had issues in the past where I've blown out the end of a blank and now cut them longer than I need for drilling, drill the hole and then trim to the length I want. This does not sound like your issue though.

 

[gbpens]

If the exit hole is off center then your blank is not parallel to the drill bit. While laminated woods such as Spectraply can cause a bit of drift when drilling it is usually the setup holding the blank or a dull bit.

 

[Daniel2025]

I just completed the pen using a regular bit ( new non brad point) with 135 degree edges. This blank came out much better. Its odd because the brad point bit has been working great, It could be getting a bit dull. Just something to look out for, learning process.

Thanks Guys

Dave