How to prevent grub screws from damaging outer diameters

[thehomeengineer]

Hi All

The video explains how I stop grub screws from damaging the outer diameter of a shaft:

Thank you for viewing and hope you find this method useful
The Home Engineer

[mklotz]

If suitable brass is not available there are other options. Lead bird shot, available from reloader suppliers in the USA, or lead split shot available from fishing gear suppliers work well as do spent air rifle pellets.

Still, wherever possible, milling/grinding a flat on the shaft where the setscrew seats is a better solution.

[thehomeengineer]

Hi Marv
Thank you for the alternative options on material selection. I have never used lead but I have used aluminium in the past.
As I am going to have different width, rollers running in bearings I did not want to machine flats on the shafts. This was purely to ensure the bearing would always have 360-degree contact to shaft. Also not using a flat means orientation is never a problem. So many times, I have gone to move a collar and the previous person has not quite lined the grub screw true to the flat and this chews the edge of the flat/shaft and both the bore of the collar and shaft become damaged, making moving the collar difficult if not impossible by hand. I think both methods have their merits.
Thank you again for viewing
The Home Engineer

[Frank S]

I have found several instances where 2 grub / set screws were used in the same hole most likely to insure positive locking.
one such time one of my guys was trying ot disassemble something I noted him really wailing away at a set collar on a bearing nothing was moving and the large expensive bearing was at the verge of being destroyed with 2 hydraulic jacks pushing against the mounting flange a 6 lb shop hammer and a large brass drift and still no movement. I asked him did you take out all 6 set screws? he said I loosened all of them off a couple of rounds. Well take them out and check to see if there are screws under them. Sure enough there were 6 more 5/8 11 3/4" long, pointed set screws once those were removed the bearing could be slid off by lightly tapping around the inner race . The 8" diameter shaft had 6 drilled location holes in it

[thehomeengineer]

If suitable brass is not available there are other options. Lead bird shot, available from reloader suppliers in the USA, or lead split shot available from fishing gear suppliers work well as do spent air rifle pellets.

Still, wherever possible, milling/grinding a flat on the shaft where the setscrew seats is a better solution.

Hi Marv
Last Night I finished machining the fabricated shaft for the ring roller I am currently working on.http://www.homemadetools.net/forum/f...g-roller-66702
As, this is the drive roller shaft there are two keys machined into it. One to drive the die and the other for the turret hand wheel to rotate the shaft/die. As the key locates the die but does not lock it along the shaft, I do not want it to move when in operation. Therefore, I have machined a flat the opposite side to the key for a grub-screw to clamp against, knowing then the orientation for the key has set the grub-screw to the flat. Therefore, no chance the grub-screw can damage the outer diameter of the shaft. UNLESS (the key is not present or the grub-screw is overtightened deforming the flat section to encroach to the shafts diameter.) Can not design out “total stupidity” completely lol
Thank you again for viewing and the posts you submit
The Home Engineer

[jjr2001]

Great ideas one and all. In particular I like Franks note about the double set screws in one hole.
Never thought of that. Good to know.

Cheers, JR

[old_toolmaker]

There have been some very interesting input here on using grub screws and some great ideas for preventing damage to shafts. I also have been in the same situations concerning double set screws and learned that lesson early on the hard way. Funny how we tend not to forget those lessons learned the hard way!

[DIYer]

Thanks thehomeengineer! We've added your Shaft Damage from Grub Screw Prevention to our Fastening category,
as well as to your builder page: thehomeengineer's Homemade Tools. Your receipt:

Shaft Damage from Grub Screw Prevention by thehomeengineer

tags: locking