Lister D - Pully Grub Screw

Any tips on removing very rusty grub screw - have tried penetrating oil and a good blast with a blow torch to get it very hot - but remains solid and my Allen keys just bend.

I could try to drill out but think made of very hard steel and drill won't touch it.

I don't actually need to remove the pully but the gib key sticks out too far and could catch on clothing etc so not very safe ( and looks not very good) so I need to remove the grub screw and then try to remove the gib key and file down so it fits in further.

drill it it will come out, its the wrong key for the pulley and it should be a parallel key, keep the drill well lubricated and sharp.

Maryalice

OK - I will get some cobalt drills and try again at drilling - do you happen to know what size this grub screw will be ??

Thanks for the advice on the Key.

It will be Whitworth but as to the diameter I don't know, you may just get a caliper on it to measure or eye it up to a drill bit by standing the drill shank on the screw head.

Maryalice

Hi there, I had a similar problem with grub screw on a lister d pulley, I bought myself a set of drills from screwfix, they are brilliant, drilled grub screw out in seconds. They were not cheap but you get what you pay for!
https://www.screwfix.com/p/milwaukee-straight-shank-thunderweb-hss-g-metal-drill-bit-set-19-piece-set/552fj

Thanks - I bought some cobalt drills from Toolstation -(https://www.toolstation.com/cobalt-pro-drill-bit-set/p68884)  expensive but hardly touched the grubscrew - I don't know what it is made of but is extremely hard.

I have managed to get the Gib key out with a lot of patience - it is a parallel key but is now well damaged so will be binned and will get a new one. It was just too long and was up against the flywheel gib key so would never have gone in further.

I have also got the pully off with a lot of pulling, lubricating, hammering, heating and cursing

I will try to drill out the grub screw using my pillar drill and freshly sharpened drills - otherwise my be easier and cheaper to try and find another pully.

I drilled out a head stud with my drill bits today and I was very surprised how easy it was. Head studs can be fairly hard!

I also had success - getting the pillar drill onto the screw did the job, slower speed but more force and lots of oil. Managed to re tap the hole and now have a 3/8 unf bolt with a locking nut to nip up the key.

That's great, sometimes just another angle and perseverance is all it needs!
I'm surprised it had a grub screw, most of the pulleys I've had and seen have had a square headed bolt.