266XP Bar Stud Repairs.

[Bob Hedgecutter]

Okay, here is one for you all to debate.
Recently picked up a nice 266XP that came with an MS201T in a deal too good to pass up.
All in all the 266 is a good strong example- only drawback was some previous owner has done a Bubba to mount Stihl bars on the saw.
Not sure if it wan intentional, or a home workshop make do for a saw that dropped one or both original studs and the owner thought it required a case split to replace them. That idea was put into the "too hard" basket and this is the result of the "fix".



So the front stud hole has been tapped for a bolt- which requires a 14mm spanner to remove- so does not fit a chainsaw scrench. Rear hole has some kind of possibly threaded in stud with a sleeve over that has been epoxied in place.



Removal of the bolt gives open access to the oil tank- so removal means unless saw is sitting in the correct orientation, oil tank empties to below stud hole level.



Rear "stud" to keep the bar from pivoting on the front bolt only.



So what is your solution?
Original bar studs (one of which was still in the oil tank- found by magnet fishing) almost friction fit to the threaded hole.
When viewed with a strong light from the oil tank filler cap- no rectangular head is visible at either stud hole- so guessing the back stud is not as snapped original with a sleeve over the stub remains to take it from D009 to D025.

So how would you deal with it?
Leave well alone?
Continue with one fixing point and Stihl bars?
Sell it to some other mug?
Remove the rear stud and JB Weld in some originals?
Have D009 type studs made to fit the threads of the front stud hole?
Swap out PTO case half for a good one?

What would you do if it were yours?

 

[MadKaw]

Helicoil (or similar) insert.

 

[Bob Hedgecutter]

Helicoil (or similar) insert.

?????? Helicoil what and why for?
Husqvarna studs are press taper fit- not threaded.

 

[MadKaw]

?????? Helicoil what and why for?
Husqvarna studs are press taper fit- not threaded.

Doesn't mean the replacement stud has to be.

 

[Bob Hedgecutter]

Doesn't mean the replacement stud has to be.

So why helicoil?
There are threads already in the case and I would have to either make or buy some other brand of studs to thread in and make it Husqvarna large mount again.

 

[MadKaw]

So why helicoil?
There are threads already in the case and I would have to either make or buy some other brand of studs to thread in and make it Husqvarna large mount again.

All I had was the picture to go on. It looked to me like the threads were damaged. If they're in good shape, obviously there would be no need to use a thread insert.

 

[Bob Hedgecutter]

All I had was the picture to go on. It looked to me like the threads were damaged. If they're in good shape, obviously there would be no need to use a thread insert.

Okay, so we don't helicoil now and stick with the original botch up threads and odd size bolt that dictates we use D025 bars and have to carry a 14mm spanner to adjust things?

 

[MadKaw]

Was there more than one configuration for the 266 over it's history? I tend to be stubborn, and I like to solve puzzles... sooooo, why not use an insert so you could use an m8 bolt instead of whatever was bodged on?

 

[Bob Hedgecutter]

Was there more than one configuration for the 266 over it's history? I tend to be stubborn, and I like to solve puzzles... sooooo, why not use an insert so you could use an m8 bolt instead of whatever was bodged on?

Not for bar studs- no. The 266 is pretty much exactly the same from initial SE to end of run XP's.
So if we put some kind of insert in for M8- are we still using a bolt or two to hold the bar in place?
This is assuming we can find M8 flange bolts that are 13mm hex drive and not 12mm hex drive.

 

[MadKaw]

The M8s in my box all have 13-mm heads. Both straight hex and flanged.

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I understand the long-term reasons for using a stud instead of a bolt when going into a magnesium case.
If you're not going to run it much, the easy fix would be to use bolts.
Longer term, I'd put in the helicoil (Torque Test Channel tested a bunch of variants, Helicoil brand wasn't the best one on their test) and lock in 8mm stud with 242 thread locker and peening the threads.

 

[Bob Hedgecutter]

If you are going to "fix" it, I see no point in a short term fix and the use of bolts still leaves the holes directly open to the oil tank innards just to remove the clutch cover and or the bar/chain.
So for me no- bolts are out.
So is threading for helicoils or any other such screw in thread system followed by loctite to hold threaded studs in place- are you familiar with the internals of Husqvarna oil tanks and how the original studs are held in place?

 

[MadKaw]

If you are going to "fix" it, I see no point in a short term fix and the use of bolts still leaves the holes directly open to the oil tank innards just to remove the clutch cover and or the bar/chain.
So for me no- bolts are out.
So is threading for helicoils or any other such screw in thread system followed by loctite to hold threaded studs in place- are you familiar with the internals of Husqvarna oil tanks and how the original studs are held in place?

No I'm not. My mechanical expertise (such as it is) has been garnered from motorcycles and outboard motors. If you're up for explaining the issue, I would be happy to learn.

 

[Bob Hedgecutter]

No I'm not. My mechanical expertise (such as it is) has been garnered from motorcycles and outboard motors. If you're up for explaining the issue, I would be happy to learn.

Okay, this is a Husqvarna 61 case I happened to have laying about and in two halves and as it is identical to a 266 case- perfect for demonstration purposes.
Note the blank unthreaded holes for bar studs and the upper and lower raised ribs. As viewed from inside the oil tank.



This is an example of the original stud (unpainted) and some aftermarket copy of the original stud (painted)- note the thin rectangular head.



This is the aftermarket stud sitting in place as it would from the factory - so to speak. Note the two raised rib areas top and bottom encapsulate the rectangular section head of the stud to prevent it from rotating.



The unthreaded section of the stud shaft should be a tight taper press fit to the stud hole, thus preventing the stud from dropping back into the oil tank reservoir.

 

[MadKaw]

OK, I get all that... and somewhere along the line the case got, to put it gently, modified, in order to accept a bolt. Right?
So... an ideal fix would be to TIG weld a plug and redrill with a tapered bit to accept a stock stud. Seems to me that would be way more than the value of the saw would justify. I admit I am not the best TIG welder around, and working with Mg would be beyond my skills.
So, why is a threaded stud so beyond the pale? I'm not seeing why it wouldn't work.

Please don't think I'm being antagonistic. (Maybe a bit stubborn... ) I'd happily make a pot of coffee to lubricate this discussion if we were in the same area.

Is it that the vibration causes the threaded insert to loosen despite thread locker and peening?

 

[Bob Hedgecutter]

Okay, the taper is widest on the inside of the oil tank eh? So in order to fill the holes with weld and then redrill to factory spec- one would have to pull the entire saw down to grass roots level to accomplish drilling the holes correctly- unless you are privy to some fancy new drill bit that bores a tapered hole from the narrow side first?

Simple fact of the matter is, the rear hole is untapped and close to original spec- the front hole has been tapped to the original drilling so top of the thread lands are original diameter, or close enough to original and I have the one original stud I found in the oil tank and a bag full of replacement studs that look just like the original.
So the expense and trouble of finding the correct heli coil parts- threaded bar studs that will suit D009 mount but thread into a case- is money and time I dont have to spend to arrive at a conclusion almost the same as original- but not the same.

 

[MadKaw]

Thanks for the discussion, Bob.
Hope I wasn't too annoying. I've always figured the secret of life is to be just annoying enough.

 

[Bob Hedgecutter]

And here is the simple repair- all completely doable from the access provided via the removed oil filler cap.
Small amount of standard JBWeld to take up the slack of the wallowed out and tapped stud holes and a bit of tension whilst it cures.



Not the easiest thing to photograph through the oil fill hole- but standard Husqvarna style studs refitted into a Husqvarna saw that had been visited by Bubba.




Will add a photo of what the rear "stud" was as the saw came to me- could be thought of as ingenious, or Redneck as heck!

 

[Cskyline]

Well it seems this would be a difficult fix and I agree that threads are not the answer with the taper bolt and tank etc . But if I did want to insert a thread in soft metal I would use an ez-loc insert have used them for years they hold better than the original threads in soft metal.