Husq 550xp. Does this require new block??

[Stoke Wood Project]

The thread shown circled here, which holds the chain brake handle, has been threaded completely. Does anyone know the best way to fix it, or is it fubar?

Cheers all

[spudulike]

The original screw has some sort of coarse screw thread. Options are to tap oversize, use an insert or helicoil the casting but from the pic it looks like the hole is now non central which may be a big issue.

Another issue is that this is a safety device and any "lash up" may fail just as you want it to work.

You can either stick with the original screw and know this to be a custom affair with a big flange to it and then match the thread for the repair or, use a standard M5 thread and use a screw and a custom bush to make up the form of the original screw.

The other option is to stick a screw right the way through and use a lock-nut on the back side of the alloy casting.

Very difficult to tell - perhaps a local decent engineer may be able to help but you have to ensure there is no compression between the hand guard and the alloy making the guard stiff and the chain brake operates as it should.

I guess you could drill straight through the original screw and then put a longer M5 screw through it with a lock nut on the back of the alloy to hold it in place!

Edited March 20, 2021 by spudulike

[Stubby]

1 hour ago, Stoke Wood Project said:

 

The thread shown circled here, which holds the chain brake handle, has been threaded completely. Does anyone know the best way to fix it, or is it fubar?

Cheers all

 

If its been " threaded completely " then there is nothing wrong with it . Do you mean the thread  been stripped ?

[bmp01]

20 minutes ago, Stubby said:

If its been " threaded completely " then there is nothing wrong with it . Do you mean the thread  been stripped ?

Here we go again....  

Think OP is going to find Spuds answer slightly more useful. For entertainment value we'll give you 9/10 for effort Stubby. I'm in agreement btw.

 

 

[Stubby]

Just now, bmp01 said:

Here we go again....  

Think OP is going to find Spuds answer slightly more useful. For entertainment value we'll give you 9/10 for effort Stubby. I'm in agreement btw.

 

 

😁😁👍

[adw]

There is so little material in this area it is very difficult to do a permanent repair, it’s not just the centre thread it’s raised section to centralise the the hand guard in that area, I fear another crankcase, or at least half crankcase.

[Stoke Wood Project]

The original screw has some sort of coarse screw thread. Options are to tap oversize, use an insert or helicoil the casting but from the pic it looks like the hole is now non central which may be a big issue.
Another issue is that this is a safety device and any "lash up" may fail just as you want it to work.
You can either stick with the original screw and know this to be a custom affair with a big flange to it and then match the thread for the repair or, use a standard M5 thread and use a screw and a custom bush to make up the form of the original screw.
The other option is to stick a screw right the way through and use a lock-nut on the back side of the alloy casting.
Very difficult to tell - perhaps a local decent engineer may be able to help but you have to ensure there is no compression between the hand guard and the alloy making the guard stiff and the chain brake operates as it should.
I guess you could drill straight through the original screw and then put a longer M5 screw through it with a lock nut on the back of the alloy to hold it in place!

Thanks very much for your comprehensive reply.
It's off centre, so I think it's beyond repair.
I want to make sure the chain brake functions properly

[Stoke Wood Project]

There is so little material in this area it is very difficult to do a permanent repair, it’s not just the centre thread it’s raised section to centralise the the hand guard in that area, I fear another crankcase, or at least half crankcase.

Yeah, that's what I'm now thinking. Thanks for the reply.

[Macpherson]

39 minutes ago, adw said:

There is so little material in this area it is very difficult to do a permanent repair, it’s not just the centre thread it’s raised section to centralise the the hand guard in that area, I fear another crankcase, or at least half crankcase.

Hi, If this is into Mag alloy it could be a perfect candidate for a HTS 2000 repair without taking the engine apart.

 

I know this method has been rubbished on here before but totally wrongly imo, since finding this method a good few years ago I've managed to save many things that would have previously been unrepairable and scrap... it for sure works on magnesium alloy castings

 

And to the OP... it's readily available on ebay and if you thought it worth a go... cleanliness and following the instructions to the T is the key to a possible easy fix, any questions, just ask. cheers.

 

 

[bmp01]

11 hours ago, Stoke Wood Project said:

Thanks very much for your comprehensive reply.
It's off centre, so I think it's beyond repair.
I want to make sure the chain brake functions properly

How about a turned (lathe) insert epoxied in ? Could have a rim on it .... so a "top hat" insert, put in from exhaust side.

Benefits are, it won't come out, top hat rim is thinner than a nut, can have the location nose on it, can take a proper thread most likely a size down on the self tapper cack.

Concerns: is there enough meat to centralise the hole and can you then file / drill a reasonable hole (doesnt need to be perfect if the insert is glued in).