Stripped thread hole repair question

[Armosh]

Has anyone ever attempted to use some brazing rod to fill a stripped hole in a saw? Then drill and tap it to the original size? Say for a chainbrake screw hole or a starter or dog mount? Would it even be possible due the magnesium case? Just want to hear some thoughts and possible solutions besides helicoils.

 

[singinwoodwackr]

Has anyone ever attempted to use some brazing rod to fill a stripped hole in a saw? Then drill and tap it to the original size? Say for a chainbrake screw hole or a starter or dog mount? Would it even be possible due the magnesium case? Just want to hear some thoughts and possible solutions besides helicoils.

Haven’t tried braising cuz I’m afraid I’ll melt the magnesium
i have, however, drilled, tapped in a 5/16” or 8mm bolt, secured it with JB weld and then drilled/tapped for 5mm/.08 and done well In a cylinder…muffler bolt hole.
am in the process of repairing a very bad top cover bolt hole in a 372. Stay tuned…

 

[a. palmer jr.]

I wouldn't try brazing it myself but I might try drilling and tapping it for a helicoil or an insert.

 

[singinwoodwackr]

I wouldn't try brazing it myself but I might try drilling and tapping it for a helicoil or an insert.

Mine was to badly augered out for a heli…I tried

 

[Bob Hedgecutter]

If it is a flogged out 5mm hole- thread it for 6mm, usually dont even need to enlarge the original hole.
If it is the like of a starter cover and you dont want to carry 4mm and 5mm hex tools with you- make the fixing slot or phillips so you can get all 4 out with the same tool in the field if you need to say replace a starter rope or something.

 

[singinwoodwackr]

If it is a flogged out 5mm hole- thread it for 6mm, usually dont even need to enlarge the original hole.
If it is the like of a starter cover and you dont want to carry 4mm and 5mm hex tools with you- make the fixing slot or phillips so you can get all 4 out with the same tool in the field if you need to say replace a starter rope or something.

Tried that...hole is too big.
I JB-ed a 6mm bolt and drilled for 4mm. It just pulled out. I'll try a 5/16" or 8mm next. The 8mm worked well for a muffler bolt hole in a husky 350.
After that...New case half

 

[Bob Hedgecutter]

Tried that...hole is too big.
I JB-ed a 6mm bolt and drilled for 4mm. It just pulled out. I'll try a 5/16" or 8mm next. The 8mm worked well for a muffler bolt hole in a husky 350.
After that...New case half

was more an answer to the OP's situation.

 

[cookies]

u try to braze mag and its likely to run away from you on fire, get a time sert kit and fix it once the right way or end up like the guy above needing a case.

 

[Pjohnson]

They make a twinsert which is a oversized helicoil with a second helicoil inside it.

 

[L34]

The last 066 I done was the old M8 bolt trick.
M8 bolt drilled and tapped to M5.
Drilled and tapped case to M8 loctited in bolt and all good.
Go cut wood.

 

[Armosh]

u try to braze mag and its likely to run away from you on fire, get a time sert kit and fix it once the right way or end up like the guy above needing a case.

I was figuring that would be the case. I got a 359 with the chain brake handle screw hole is wallowed out conically. No idea how that happened. Came to me that way. So I can't really go up a size and it uses that special screw with the big collar on it for the handle to pivot on.

 

[spuldup]

In the mag I have used JB weld. I would not think applying fire to mag would end well. In plastic, 5 minute epoxy works well.

None have failed me yet.

 

[ZeroJunk]

The last 066 I done was the old M8 bolt trick.
M8 bolt drilled and tapped to M5.
Drilled and tapped case to M8 loctited in bolt and all good.
Go cut wood.

I have to say I had not thought of that. Cool.

If the threads are just stripped and not wallowed out you can get a little meat by tapping 5MM to 12-24 SAE, and 6MM to 1/4 -20 . 12-24 SAE Allen heads will slip in the recesses in Stihl mufflers.

FWIW

 

[lone wolf]

I have to say I had not thought of that. Cool.

If the threads are just stripped and not wallowed out you can get a little meat by tapping 5MM to 12-24 SAE, and 6MM to 1/4 -20 . 12-24 SAE Allen heads will slip in the recesses in Stihl mufflers.

FWIW

Why not use aluminum round stock, it's easier to tap?

 

[ZeroJunk]

Why not use aluminum round stock, it's easier to tap?

Talking about going to 8MM , most places that screws strip on a saw, weed eater, or blower, there is not enough room for that.

 

[muddy42]

I have found helicoils work well if you take your time and prepapre well. For blind holes that dont go all the way through, you may need to use/make a square cut tap and/or make the helicoil itself shorter.

 

[singinwoodwackr]

I've discovered the hard way that tapping for helicoils requires a second, modified, ie ground, tap to make the bottom of the hole flat with no taper in the depth of the hole. Otherwise the coil tapers at the bottom and your bolt won't seat all the way. Removing coils is nearly impossible and trying to tap them after the fact only breaks taps

 

[muddy42]

I've discovered the hard way that tapping for helicoils requires a second, modified, ie ground, tap to make the bottom of the hole flat with no taper in the depth of the hole. Otherwise the coil tapers at the bottom and your bolt won't seat all the way. Removing coils is nearly impossible and trying to tap them after the fact only breaks taps

Totally agree. Very well explained, thats what I was trying to say.

 

[ZeroJunk]

What I wish is somebody would tell me the trick to getting the hole drilled straight. Doesn't matter much on a screw hole. But, on a bar stud if you are off angle just a little the cover won't fit.

 

[Pjohnson]

I've discovered the hard way that tapping for helicoils requires a second, modified, ie ground, tap to make the bottom of the hole flat with no taper in the depth of the hole. Otherwise the coil tapers at the bottom and your bolt won't seat all the way. Removing coils is nearly impossible and trying to tap them after the fact only breaks taps

Its called a bottoming tap if your looking for one.