• We invite you to join UKWorkshop.
    Members can turn off viewing Ads!

Grub Screws

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

mr

Established Member
Joined
28 Jun 2005
Messages
1,737
Reaction score
0
Location
Devon
This may be a daft question (sorry) but when fitting grub screws into wood does the predrilled hole for the screw need tapping for the screw thread or do they work in a similar way to a threaded inset ie cutting themselves a grip in the wood as they are driven in?
 

MikeW

Established Member
Joined
15 Apr 2005
Messages
1,933
Reaction score
0
Location
Forest Grove, Oregon USA
mr":kbu0hmpn said:
This may be a daft question (sorry) but when fitting grub screws into wood does the predrilled hole for the screw need tapping for the screw thread or do they work in a similar way to a threaded inset ie cutting themselves a grip in the wood as they are driven in?
Hi Mr,

I tap the holes. I use Allen head bolts for some jigs I've built and for all small hinges I use brass flat head bolts of appropriate size and also tap the holes for those.

Take care, Mike
 

Chris Knight

Established Member
Joined
14 Jan 2004
Messages
6,641
Reaction score
3
Location
SE London - NW Kent
Machine screws hold very well in most hardwoods - better than woodscrews according to some research Lee Valley did years ago. However, repeated screwing and unscrewing will weaken the fixing and there needs to be enough thread engaged to provide a firm fixing.

When tapping, do it just like metal and back off the tap a bit each half turn or so. This makes a cleaner thread than just winding the tap in - which you can do in wood, unlike metal. Use a bit of wax for lubrication for a cleaner thread too.
 

mr

Established Member
Joined
28 Jun 2005
Messages
1,737
Reaction score
0
Location
Devon
Thanks all. Questions definitely answered there. Now off to see if I can find a tap set small enough failing that time for a rethink. THanks again.
Mike
 
Top