Quantcast

Drill Bit Sizes - Pen Turning

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

Hesh

Established Member
Joined
20 Feb 2011
Messages
126
Reaction score
0
Location
Camberley, Surrey
I've just ordered some more upmarket Pen Kits as I need to make a few leaving gifts for work and noticed the drill bit sizes are all in imperial. I've got a mountain of Metric bits but no imperial sizes and was wondering if the sizes are absolutely critical (if so I'll order some) or is the metric equivalent ok to use.

Sizes I need are

27/64 which is 10.7156 (10.5mm?)
25/64 which is 9.9219 (10mm?)
15/32 which is 11.9063 (12mm?)

Would appreciate any coments from all the Pen Turners out there.

Steve
 

nev

Established Member
Joined
21 Jan 2011
Messages
4,858
Reaction score
10
Location
The green and wetter end of the M4.
IMHO If you use PU glue that expands a bit on setting you can get away with the 10mm and the 12mm but the 27/64 is too tight for 10.5 and a little too loose for 11mm.
If you want a 15/32 jobber pm me your address and I'll pop one in the post. I bought a box of five when i was looking for the same and if i get to the point where I break 4 I'll give up woodworking!

If you have difficulty finding the imperial sizes funeturnz have some sets.... http://www.ebay.co.uk/itm/Woodturning-H ... 4602e35976
 

jumps

Established Member
Joined
29 Nov 2010
Messages
937
Reaction score
0
Location
kent
Steve,
I don't think there's a simple answer to the general question. A lot depends on how they arrived at their recommended dril bit size in the first place - some will be metric tubes marketed for the US market and hence quoting imperial sizes. There's also a small variation in the 'glue gap' that can be inherent in the recomendations - here I may go a little tighter if the wall thickness after turning is going to be thin and I'm confident I can drill very cleanly.

Generally I now measure the tubes when I get a new kit type and work from there. Even to the extent of testing with a bit of scrap if I'm not sure.

btw if the 27/64" is for the Sierra kit, it's a 10.5mm bit - an example of why you can't generalise!
 

Hesh

Established Member
Joined
20 Feb 2011
Messages
126
Reaction score
0
Location
Camberley, Surrey
Nev, thanks very much PM sent and appreciate your advice.
Jumps - yes it is for the sierra and have plenty of 10.5mm bits so that's a start thanks for the advice.

Will experiment with the tubes and bits once they get here and will look at taking any slack up with different glues once completed I'll post the results.

regards

Steve
 

CHJ

Established Member
Joined
31 Dec 2004
Messages
20,068
Reaction score
33
Location
Cotswolds UK
And don't assume the next batch of kits have the same drill requirements. Not unknown for a tube with a differing wall thickness to be supplied.

And as already eluded to, best to always drill with with drillbit to hand and a sample of the wood/plastic if you have a spare sample, especially if it's one that has been sharpened, a small deviation in the web offset at the point can make a considerable difference on the resultant hole size.

In fact if you have a drill that is a fraction too small in diameter, sharpening off-centre can be employed to make it drill oversize.
 

Hesh

Established Member
Joined
20 Feb 2011
Messages
126
Reaction score
0
Location
Camberley, Surrey
Thanks Chas, I will have to remember to check each batch and not do my normal trick of believing they will all be the same and you never know I might not waste as many.

Steve
 

Neil Farrer

Established Member
Joined
3 Jan 2012
Messages
233
Reaction score
0
Location
Hitchin
This has got to be the most debated and repeated topic on pen turning forums. I make around 2,000 pens a year. If you would like me to justify my point of view I am happy to. Last time it ran to around two pages of A4. Simply, get the right size drill. And that means the right size drill for the tubes, not what some suppliers (not manufacturers) say. Some, including the larger shops in the uk have been knwon to do a metric conversion. Bear in mind that other than 7,8 and 10mm tubes almost all others are imperial, so if a kit says, drilll bit required 10.5mm - beware!!! similarly 14.5mm or whatever the metric conversion is for 37/64.

Inevitably you have to go to the larger size metric drill bit. If you do that and then drill a soft wood, spalted beech for example, the hole will be even bigger. It won't work. The correct size drill bits will cost you around £1.50 each. You can pick these up from any engineering supplies shop, don't order them from the woodturning supplies shop beacuse they wont have them and where they do they will be expensive. The colt drills are good, but only the bits larger than 8mm, so 11/32 10mm 27/64. Te 7mm and the 8mm suffer from deflection if there is any variation in the density of the wood or if you have any angle whatsoever on the face.

I'm sure that others will have varying views, they always do, its up to you!
 

jpt

Established Member
Joined
23 Feb 2007
Messages
1,183
Reaction score
0
Location
Peterborough
Neil Farrer":ouw1ytw2 said:
This has got to be the most debated and repeated topic on pen turning forums. I make around 2,000 pens a year. If you would like me to justify my point of view I am happy to. Last time it ran to around two pages of A4. Simply, get the right size drill. And that means the right size drill for the tubes, not what some suppliers (not manufacturers) say. Some, including the larger shops in the uk have been knwon to do a metric conversion. Bear in mind that other than 7,8 and 10mm tubes almost all others are imperial, so if a kit says, drilll bit required 10.5mm - beware!!! similarly 14.5mm or whatever the metric conversion is for 37/64.

Inevitably you have to go to the larger size metric drill bit. If you do that and then drill a soft wood, spalted beech for example, the hole will be even bigger. It won't work. The correct size drill bits will cost you around £1.50 each. You can pick these up from any engineering supplies shop, don't order them from the woodturning supplies shop beacuse they wont have them and where they do they will be expensive. The colt drills are good, but only the bits larger than 8mm, so 11/32 10mm 27/64. Te 7mm and the 8mm suffer from deflection if there is any variation in the density of the wood or if you have any angle whatsoever on the face.

I'm sure that others will have varying views, they always do, its up to you!
I dont make quite as many as you but I agree with what you say here, I have a Cromwells branch http://www.cromwell.co.uk/ close to me and if they dont have the drills in stock they can usually get them for the next day, or you can get them amil order.

john
 

Hitch

Established Member
Joined
28 Jan 2006
Messages
639
Reaction score
0
Location
Somerset
I have ruined (as no doubt many others have) a few tubes/blanks purely by drilling the wrong sized holes. Make it too tight and the tube gets half way and sticks.

Measure the tube, then make it fractionally larger seems to work for me, especially in acrylics and harder woods.

Cant remember which pen kit it was but I have a bit which I ended up grinding down a touch to reduce the diameter.
 

Hesh

Established Member
Joined
20 Feb 2011
Messages
126
Reaction score
0
Location
Camberley, Surrey
Thanks Hitch, pen kits and various drill bits have now arrived so now all I need is the time to get into the workshop to go through all of the suggestions. I've turned pens before but whilst I dont mind making mistakes with the standard slimline pens I want to give myself every opportunity to get the more expensive kits right.

I'll let you know how I get on.

regards
 

Hesh

Established Member
Joined
20 Feb 2011
Messages
126
Reaction score
0
Location
Camberley, Surrey
Thought I'd post the result of my first attempt with a reasonable kit which is a Gatsby from pencrafts, also the first time using an acrylic blank (woodland camoflage). The advice re drill sizes came in handy as although I used the "correct size" the bushings I bought with the kit didnt fit the tube so I had to ream the inside of the tube with a small spindle gouge.......... The blank was sanded with micromesh down to 12000 which made it glass like in appearence. The pen is a gift for my brother so no prizes for guessing what he does for a living. Anyway C&C welcome as always.

Regards

Steve
 

Attachments

Top