Drilling pen blanks in the lathe - problem

[Jensmith]

Hi all,

I was trying to drill one of my pen blanks on my little Sieg C0 baby lathe today (it is the first time I've tried it) with a 7mm twinland Lip & Spur drill and I only got about 1 cm in, in small stages, clearing the chips, before it started screaming at me, really loud and high pitched.

I was drilling into a spalted horsechestnut blank and it's pretty soft wood so I wouldn't have thought it would cause any problems.

The half blank was mounted in my 3 jaw chuck (I turned it round first) and the drill is static in the drill chuck on the tailstock.

EDIT: I had the lathe running at near it's fastest speed at about 2500 - 3000 rpm

Any ideas as to what might be wrong?

 

[Blister]

Was the Jacobs chuck turning in the tailstok ?

or the drill spinning in the Jacobs chuck ?

unless the drill was blunt I cant see its the drill

but the speed is way to high

 

[Jensmith]

Only the blank was spinning. The drill and drill chuck were stationary and it's a brand new drill.

Could it just be too high a speed then? What speed would you recommend?

 

[Blister]

500 rpm should be plenty , keep withdrawing the drill to clear the cuttings and keep the drill clean

 

[CHJ]

As Blister says, drill speed far to high, at those speeds you are heading for a good demonstration of how to make fire Jen.

 

[laird]

+3. Minimum speed (500 ish) plus frequent withdrawing to clear the bit.

 

[jpt]

As the others have said the speed was way too high I drill them at 500rpm as a max speed.

My guide to drilling on the lathe is HERE which might be of help to you.

john

 

[Jensmith]

Ok, I'll try that tomorrow. Thanks guys.

 

[tekno.mage]

I'd agree with everyone else that you were trying to drill at way too high a speed, but having said that, some wood does scream when drilled (even at a reasonable speed).

I've had ash do it - I was drilling out the centres of some ash pen pot blanks with a 25mm forstner and one of the 4 blanks did the screaming thing even at a slow drill speed and plenty of stopping to clear chips and cool the bit. I later found out why - there was a small split I hadn't noticed in the blank!

 

[como]

I would normally recommend giving the drill bit a wipe with a bit of hard bee's wax or a candle, this will stop the screeching.

But since your drilling for a pen blank, it's probably not a good idea, because the wax will interfere with the glue when you stick the tube in.

However, for general hole drilling on the lathe, a bit of wax works wonders.

 

[Jensmith]

I had another go today and it was much better but there was still a bit of screeching when the drill was being withdrawn so I think it must be down to a wobble of the drill or something when the drill is being withdrawn.

It's not the highest quality lathe in the world.

In the end I switched the lathe off when I withdrew the drill to clear the cuttings and switched it on again once ready to continue cutting and that seemed to work ok. No screeching anyway.

 

[Bluefoxy]

When you are drilling the bit is held in tension and tends not to wander. If you withdraw the drill with the lathe running it will wander as you have relieved the tension. This will cause the screeching and more importantly may enlarge the hole. So you are right to stop the lathe and then withdraw the bit. I'm not familiar with your lathe but I have made quite a few pens and have found that the most difficult job by far is drilling the hole for the tubes. I have also found that the "bullet" type drills are better than lip and spur bits.

http://ukpenkits.com/catalog/extreme-drill-p-127.html

It is also most important that you keep the bits sharp!

Ray