Removing a rusted saddle grub screw

[umcoo]

I picked up an old Yamaha BB400S a few weeks back with a view to slowly but surely getting it into playing condition again. It's going ok, other than one rusted grub screw in one of the bridge saddles.

My allen key slips when I get hold of it, I've tried pliers to twist it, covered it in wd40, let it soak in a bath of vinegar overnight and it still won't budge. Anything else that I can try before I resort to just getting a new saddle?

Cheers

[KingBollock]

You can try soaking in cola overnight. Then see if you have a flathead screwdriver with a tapered head that you can hammer into the Allen hole and try turning it. Other than that you'd have to drill it out.

[HowieBass]

I think the vinegar solution does the same as cola (converting/dissolving rust). I've seen stuff on TV where people heat up stuck bolts (usually on old cars) to get them out but I don't know if that's practical in this case. You'll obviously need a new grub screw so I wonder if it might be easier to just replace the whole saddle assembly?

[Muppet]

Take it to bits as much as possible and heat it. I used the gas hob (Mrs Muppet wasn't pleased) and mole grips...

[3below]

If none of the above work, you may be able to drill it out and then use an 'easy out' or allen key driven into drilled grub screw to remove the drilled grub screw. Drilling this accurately with a 2 or 3mm bit will require a pillar drill. Simpler answer as suggested is new saddle. Post a picture and some dimensions, you might be surprised what people have in their spares boxes

Edited July 4, 2016 by 3below

[umcoo]

Cheers all. Didn't think of heating in so will give that a try. I guess I could just put a soldering iron on the grub screw to see if that makes a difference.

It's a flat bottom saddle which I can't seem to find too easily online. I'll stick a picture up later when I'm home.

Thanks all

[No lust in Jazz]

One thing that you might try is to remove the offending saddle and rather than try screwing the grub screw out, grip the portion of the screw that's through the saddle and unscrew the saddle from the screw.

[geoffbyrne]

Don't heat the grub screw - it'll expand & be harder to move - heat the saddle which, hopefully, will expand more than the screw and allow it a bit more room to turn.

G.

Edited July 5, 2016 by geoffbyrne

[KingBollock]

[quote name='geoffbyrne' timestamp='1467723827' post='3085630']
Don't heat the grub screw - it'll expand & be harder to move - heat the saddle which, hopefully, will expand more than the screw and allow it a bit more room to turn.

G.
[/quote]
Surely if the saddle expands it'll squeeze the grub screw even tighter?

Wouldn't it be better to freeze it?

Although, causing any expansion and/or contraction might just be enough to break the hold on the screw. So, maybe, heat and then freeze?

[HowieBass]

Reading this online about why heating can help:

"Heat- If you paid attention in chemistry class you would have learned that when you heat and cool metal it expands and contracts. The way that I have used in the past is to heat the head/body of the bolt until it is almost red hot. By doing this the bolt expands due to the heat, and when it cools it will contract thus breaking the corrosion in between the threads. A similar method is to heat the area around the bolt to make the hole it is threaded into actually expand and open up a little bit so that the bolt fits a bit looser and can be threaded out."

[Jono Bolton]

I had the same problem (there's a thread about it on here) but after a month or so of trying to get the bugger out I gave up and just bought a new bridge.

[umcoo]

Yeah, for the sake of completing this thread...

Tried heating with a soldering iron, nothing. After a few days of trying all sorts, I just bought a new bridge and pinched the saddles off it.