Welcome to Project Dalek

You need to be a member in order to access our content.


Click Here To Join!


For instant access to the plans and all Forum features, choose Active Membership.


Flat Bit Or Forstner Bit For Drilling Ball Joint

4 posts in this topic

I've got these two 4" beechwood wooden balls for ball joints:




What should I use to drill out the 1" and 1.5" diameter holes: a flat spade bit or a forstner bit?


Thanks for any help you can offer.




Share this post

Link to post
Share on other sites

Hi Ian,


I drilled a pair of Birch wooden balls for my build using flat bits. I advanced them pretty slowly and they cut ok. I bolted the balls between two pieces of wood with circular holes in - just like the way they are held in the Dalek itself, then clamped the whole thing to the pillar drill table.


When I did mine I drilled each one halfway, then turned it upside down and drilled it through until the holes met in the middle. They lined up well, but I did have the luxury of a pre-drilled 6mm pilot hole to keep them on track. If you can find a drill long enough to make one I'd start with that.


Best of luck with this!




Share this post

Link to post
Share on other sites

Hi Ian. Personally I would go with the forstner bit. The flat/spade bits are very hard to control and not very accurate either. You also seem to get a lot of break out as well.


The forstner bit gives a more accurate and cleaner cut. As Jonathan says above, try to pilot drill the holes first then widen with the forstner. Nice balls by the way!





Share this post

Link to post
Share on other sites

To report back here:


With one vote for each, I let the friend whose pillar drill I was using have the deciding say – and he suggested forstner. So I bought a couple of Planet Long Series forstner bits, and drilled out those holes. Drilling all the way through, I splintered the exit holes a little, and a couple of the screws holding the supporting frame together grazed the balls – but nothing a little filler can't fix.


Things I'd do differently next time:


- Use a pillar drill with sufficient vertical movement to drill a ball in one go. The bits were plenty long enough, but there wasn't enough vertical movement in the drill to descend 4 inches. So halfway through drilling each ball, we had to stop the drill and wind up the base plate. The bit head helped keep everything nearly aligned around a vertical axis, but there was a little lateral movement, resulting in a slight kink in the tunnel. I had to do a lot of hard sanding afterwards inside each hole to allow easy passage for the tubes.


- Lots of good bracing. I used an old resin ball joint bracket from my disassembled dalek, with screws in each corner onto a wooden base plate, to hold each ball in position. But there was a lot of vibration, which may have contributed to a not-quite-perfect cut.


- I'd consider drilling 9/10ths the way through from one side, and then turning the ball over and cutting in from the other side to avoid any splintering of the exit hole.





Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now