Bar slot ?'s

[qbilder]

Sorry for all the questions. I'm kinda new to CSMing. Have always had chainsaws but nothing real big til now.

The bar slot in the bigger saws are wider than small saws. For instance, my ms390 can run a 25" bar, 3/8, .063". My 084 can run the same specs, but not the bar would need to have a wider slot. I cannot interchange the same bar between the two saws, even though they can run the exact same chain. When buying a bar, how do I know it will fit the 084? Is there a number or measurement I should be aware of? Thanks

 

[excess650]

Stihl uses at least (3) different bar slots. The smallest saws get the really small bars as used on the MS170, 200t, etc. The next size(12mm) fits the 024 through the 066/660. The 088/MS880 uses a larger bar, 14mm slot IIRC, that is share with some of the older, larger Stihls like the 090, 076, 070, 056, etc.

 

[MHouse1028]

I ran into the same issue with my two 084's.it makes it alot harder to find the long bars for the big stihls

 

[qbilder]

Say a fella could machine new studs to use 12mm bars on the 084. Would the narrower bar create a dangerous problem?

The 14mm slot bar is 1.25" from tip to tip at the base. The 12mm slot bar is 1" from tip to tip at the base. Am I going to cut my face off if I try this?

 

[excess650]

I doubt that it would cause an issue. Husqvarna uses their large bar mount for all current saws from 365xt to 3120. What you'll need to check is the bar tail contours, oiler hole and adjuster hole locations.

I'm looking at A Bailey's catalog and see Oregon bars in the 12mm mount to 42", WP (Cannon) to 50", and the 14mm WP from 37" to 84".

Be aware that you'll lose ~6" bar length when using the mill, so a 42" bar will work on a 36" mill, but the 36" mill will only cut 34" width max. You may want an auxiliary oiler on longer bars depending upon how long the bar is and how much your saw puts out.

I'm in the process of moving up from a 36" bar on my 066BB to a 42" on my 3120. On my 36" mill I'll only gain a couple of inches maximum width, but the 3120 shouldn't have any problems chewing through where my 066BB seems anemic.

 

[BobL]

I have made up bar bolts for both directions.

These were made so an 066 could use big bars without adapters.

The extra length is so that my mills can bolt direct to the bar bolts rather than the bar.
I've also machined up some adapters from some 14 mm tensile steel bolts that slide over the 12mm bolts on the smaller saws, adapters can also be mades from coiled springs.

I also machined up some 12 mm bolts so the 076/880 can run the smaller bars but I have never used them

In terms of mechanical loads on bar bolts while milling, this is not a problem if the bar is held at both ends. The 14mm bolts used on big bars and big saws are only required when long bars are held at one end as in regular cutting.

One issue I noticed with replacement bar bolts is that they need to be very tight on the saw housing or they will come loose. Being reluctant to really crank down on these I used loctite to hold them in place but then this becomes a PITA when you want to change them. An alternative is to cut the saw housing end threads on the bolt somewhat oversize but then they all need to be oversize. After I got my 441 which handles everything up to 18-20" my 066, 076 and 880 all have big bar bolts on them

 

[qbilder]

Very cool, Bob. That's pretty much reverse as to what I was thinking of trying. I just want to be sure the narrow bar won't make it easier for the sprocket to throw chains off.

 

[qbilder]

What you'll need to check is the bar tail contours, oiler hole and adjuster hole locations.

Good thinking. Will do that.

 

[qbilder]

Looks like going smaller on the 084 isn't going to be easy. The bar adjuster is offset to the head of the screw that holds on the chain guard plate, so the offset equals the slot width on the bar. Could put bushings on the studs of smaller saws to use the 084 bar on them, but putting small bars on 084 isn't going to happen with simple stud swap.

 

[TPA]

You can get large mount bars from 16" to 84" so you shouldn't need to adapt to the smaller mount unless you really want to.

The first four numbers for the large mount bars is 3002, so go to ebay and type "stihl 3002"

The large mount "3002" bars are common to 050,051,075,076,084,088, and 880. I think the 070 and 090s have a different mount, and the 056 uses the mid size bar mount.

You can also search ebay for a bar from each of those power heads, for example "075 bar"

 

[TPA]

I used loctite to hold them in place but then this becomes a PITA when you want to change them.

Have you tried Nylok or equivalant product. They make a high temperature version called Nytemp. It's a nylon coating that is meant to be applied to a couple of threads. It does not act like a glue like loctite does, the nylon coating just increases the friction like a nylon inserted nut does. I think its a liquid that you can apply to the stud threads.

 

[BobL]

Have you tried Nylok or equivalant product. They make a high temperature version called Nytemp. It's a nylon coating that is meant to be applied to a couple of threads. It does not act like a glue like loctite does, the nylon coating just increases the friction like a nylon inserted nut does. I think its a liquid that you can apply to the stud threads.

The nylon type coatings work well for vibe but the main problem is when the bar nuts are undone sometimes that will undo the bar bolts if they are not well and truly held in place.

 

[BobL]

You can get large mount bars from 16" to 84" so you shouldn't need to adapt to the smaller mount unless you really want to.

I think he already has the smaller bars ?

 

[qbilder]

I think he already has the smaller bars ?

That's correct. I was just trying to pinch pennies by using the same bar on any saw I have.

 

[qbilder]

The first four numbers for the large mount bars is 3002

That is very handy to know. Thank you! Makes it much easier to know if a bar is suitable or not.

 

[mtngun]

You also have to ensure that the oil hole is in the right place.