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I have a question …..

P

PeterB

Apprentice Member
Joined
Jan 13, 2024
Posts
2
Location
Warrington
First Name
Peter
Why are the drill holes in my blanks wider the start of drilling the blank? I am drilling holes in the blank on the lathe, but the drill wanders away from the centre for a millimetre or so leaving the hole with a gap between tube and blank.
I am trying to up load a photo but can’t for some reason.
Any advice welcome.
 
pittswood

pittswood

Fellow
Joined
Mar 14, 2016
Posts
1,343
Location
Rhigos, South Wales
First Name
Kelvin
Only two reasons holes can wander, (1), the sides of the drills cutting edges are not the same length, all drills should be 118° point and you need to start with a centre drill before drill your tube diameter.
(2), Ensure you are not cutting at a negative point.
Even new drills need to be "touched" up before using.
Drill at a slow speed without screaming and don't push the drill in to fast.
Also, I find holding the tailstock quill when drilling helps against any chatter or digging in one side only to start.
Hope this helps.
Kelvin
 
C

Curly

Graduate Member
Joined
Nov 3, 2019
Posts
469
Location
RM of Aberdeen, Saskatchewan, Canada
First Name
Peter
On cheaper lathes the tailstock may not be aligned to the axis of the headstock. Your bit will touch off centre making the hole bigger before straightening some where it exits. Most of the time it can be minimized by holding the tailstock to one side or the other of the lathe bed when you tighten the locking handle. Quick way to check is to put the tips of good centres, one in the headstock taper and the other in the tailstock to see if the points touch.

Pete
 
Chriscb

Chriscb

Full Member
Joined
Feb 23, 2014
Posts
207
Location
Sutton Coldfield
First Name
Chris
What Kelvin said, with emphasis on the centre drill - ALWAYS use a centre drill. Slow and steady is the game, especially in acrylics. I tend to use DeWalt bullet drills when making kit pens.

Do let use know what you've found/how you get on.

Chriscb
 
flexi

flexi

Executive Member
Joined
Sep 12, 2014
Posts
6,520
Location
Maidstone
First Name
mark
It can also be heat build up on acrylic, if the swarfs not clearing it makes the bit a little bigger and friction will do the rest as it tries to exit the blank:duh:
 
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