Thread Repair in Al Cylinder

[calcutta250]

I am working on a Husky 394xp. The side av cylinder thread is stripped. I was thinking about getting JB Weld and plugging it and retapping it. But I’m worried about the thermal expansion.

Ant advice and recommendations would be help. I’m a machinist by trade so I would immediately think freeze plug. But I don't have all the tool needed.

 

[Canadian farm boy]

Heli-coil or timesert or get the stripped hole welded full and then drill and retap.

 

[calcutta250]

Heli-coil or timesert or get the stripped hole welded full and then drill and retap.

Ya I thought about a helicoil. I may go that direction.

also the hole that holds the chain plate on is stripped. So it’s magnesium. Might to decide to heli coil that too.

 

[Maintenance Chief]

Ya I thought about a helicoil. I may go that direction.

also the hole that holds the chain plate on is stripped. So it’s magnesium. Might to decide to heli coil that too.

Epoxy doesn't like vibes in that application. Heli coils work well.

 

[Al Smith]

Depends but often times an M5 hole will tap out to M6 . Use a spiral point first then a bottoming two flute tap . Don't even waste your time trying to use a 4 flute tap on aluminum .It will go in but often times won't come back out .

 

[AVB]

Depends but often times an M5 hole will tap out to M6 . Use a spiral point first then a bottoming two flute tap . Don't even waste your time trying to use a 4 flute tap on aluminum .It will go in but often times won't come back out .

Just got to know the tricks when tapping aluminum as I use 4 flute to tap most aluminum holes here. The main thing to use the right cutting fluid [its not oil] when tapping and back out several times to clear the chips.

 

[calcutta250]

Depends but often times an M5 hole will tap out to M6 . Use a spiral point first then a bottoming two flute tap . Don't even waste your time trying to use a 4 flute tap on aluminum .It will go in but often times won't come back out .

I hadn’t really thought about going up a size. I’ll give that some good thought.

I’ve tapped a lot of holes in various metals. I appreciate the advice though.

 

[Wonkydonkey]

Just got to know the tricks when tapping aluminum as I use 4 flute to tap most aluminum holes here. The main thing to use the right cutting fluid [its not oil] when tapping and back out several times to clear the chips.

can I ask What fluid you use

 

[AVB]

It simple as can be. 90% isopropyl alcohol. I learned this from my machinist friend as I breaking taps too. It something to do with aluminum properties so that makes the difference. OIl causes the chips to stay too close the cutting threads and jam the tap.

Since then in 5 yrs I have only broken one tap and that while doing a steel mower deck using oil as I should, just got too aggressive turning the tap.

 

[calcutta250]

can I ask What fluid you use

In aluminum WD40 works great. My second choice and first choice for most everything else is Tap Magic

 

[Al Smith]

More times than not I use "tap magic" for aluminum .I've got several small cans before I retired .Other than that about any oil will work but again only use two fluke taps never four fluke because they will bind .Small taps aren't that expensive on flea bay most of the time . They do make three fluke taps but those are for larger holes than you'd find on a chainsaw .---more --

 

[Al Smith]

Now talking about holes a tip .Rule of thumb drop one thread spacing and that's the hole size on metric or SAE .SAE threads are given in threads per inch .Metric is spacing thread to thread or land to land .A simple one 3/8" -16 would be 5/16". Now of course you can look it up on a thread chart .