Sheared cartridge bolt in headshell

[BigE]

Any idea how to remove a cartridge bolt that sheared off in an aluminum headshell?

 

[maxhifi]

Is the hole threaded, and screw installed from bottom?

 

[BigE]

It appears to be sheared at the top. It is a terminator arm. Unless someone has remounted the other fixings. I bought this recently and did not notice the issue.

 

[MAAC0]

I would try the drill and then remove the remnants from the threads with a sharp jig, Or a dremmel with an engraving bit and try to engrave a line in order for the screwdriver to grab.

 

[BigE]

Here is the other side. It looks like the previous owner was forcing a bolt that was too big.

 

[rayma]

Is the matching hole threaded?

 

[BigE]

Yes.

 

[rayma]

Yes.

I'd try engraving a line, add lots of thin oil, and try unscrewing it from the broken side.

 

[BigE]

so I need to buy a Dremel? It just occurred to me. It could also be the stuck screw has wrong pitch. It too big, else it should not shear. As it was going through from the top. Odd thing to do....

 

[rayma]

It could also be the stuck screw has wrong pitch..

It's common for small size wrong thread screws to shear off.

 

[nigelwright7557]

A possibility is to drill it out and use a bolt and nut with lock washer ?

 

[BigE]

Thanks to everyone for the ideas. I'm going to finally get the Dremel and give it a shot. But first penetrating oil and a dental pick. The shear is slightly proud on one side.

 

[BigE]

A possibility is to drill it out and use a bolt and nut with lock washer ?

I'd rather not. There are two holes behind the threaded ones that are suitable for that sort of mounting.

 

[BillWojo]

If it's not seized up in the aluminum you can usually get them out pretty easily. I run into lots of broken bolts on my job. I usually will use a small center punch and punch the surface of the broken bolt off center but not to close to the edge. We don't want to lock the threads together. At that point I carefully tap the surface with the punch at an angle to try and unscrew the bolt. The center punch mark that you made first is the place you drive it from.

If the threads are not seized up or the bolt bottomed out I can almost always get them out. The last resort is drilling and tapping.



BillWojo

 

[BigE]

Thanks Bill. That's going to be the first effort

 

[wiseoldtech]

so I need to buy a Dremel? It just occurred to me. It could also be the stuck screw has wrong pitch. It too big, else it should not shear. As it was going through from the top. Odd thing to do....

Well, if you want to perform operations such as this, yes, you must have the proper tools on hand and..... know how to use them.
It all comes with the trade.

 

[maxhifi]

Mark center of broken screw with a punch, drill hole as large as you can while still leaving some screw left, and then use these to get it out

Irwin Industrial Tools 53535 Spiral Screw Extractor Set, 5-Piece Irwin Industrial Tools 53535 Spiral Screw Extractor Set, 5-Piece: Amazon.ca: Tools & Home Improvement

I'm pretty sure the smallest one has a good chance of working here. It may also just come out while you are drilling.

 

[BigE]

What size tap is the cartridge bolt supposed to be?

 

[levistubby]

Presumably the screw is steel. Be very careful when trying to drill it as the drill will easily wander into the softer aluminium arm. You really need a drill press.


I would drill a small hole right through the screw (small enough to keep away from the threads). Then gently use the tapered square tang of the miniature file to try to turn the screw in either direction until there is enough showing to get hold of. Gently heating the arm with a hair dryer should help as it will expand away from the steel screw.

 

[BigE]

sounds like I should take it to a machine shop.