String trimmer blade opinions

[JRM]

I'm looking at a blade for my fs91r to be able to cut heavier weeds/brush than a line trimmer can handle. I see some different designs from a 3 blade to something resembling a circular saw blade. The 3 blade deal looks like they could be sharpened but I question the effectiveness of the cut without bogging the machine down. It looks like they could potentially get wrapped up in the weeds. What works best for you?
Thanks!

 

[Bill G]

This has been widely discussed many times so it will be interesting to see the new opinions.

 

[TheJollyLogger]

I agree on the 3 blade, too easy to get a little aggressive and stall. I like a good, emphasis good quality saw style on anything up to 1", and then the disc with chainsaw teeth up to 3-4".

 

[JRM]

I agree on the 3 blade, too easy to get a little aggressive and stall. I like a good, emphasis good quality saw style on anything up to 1", and then the disc with chainsaw teeth up to 3-4".

Do you have a recommendation on brand?

 

[KRP]

Does your FS91r come with the solid shaft? I have the FS80r with the flexible shaft and I did not like the 4 blade, too much vibration.

 

[TheJollyLogger]

Do you have a recommendation on brand?

I'm always going to go with stihl, but any decent name brand should be OK, just avoid the Amazon 5 for 10s and the Chinese knockoffs

 

[Bill G]

This is my Stihl FS550 that I ran the Stihl three blade on today. The Stihl 3 blade is a heavy bllade and I am not sure I would run it on a small unit

 

[Snowd]

I run the Stihl brush knife (3 blade) on my FS130 and it does very well on brush less than 1 in.

 

[JRM]

Does your FS91r come with the solid shaft? I have the FS80r with the flexible shaft and I did not like the 4 blade, too much vibration.

Yes it is a straight shaft.

Edit : it also has the solid shaft.

 

[ChuckMI]

https://www.amazon.com/dp/B08HYXSHJ...industrial&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw I have the Forester version of this but don't see it on Amazon today. An FS91 can't handle anything bigger than a 7" blade in this style.

 

[JRM]

https://www.amazon.com/dp/B08HYXSHJ...industrial&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw I have the Forester version of this but don't see it on Amazon today. An FS91 can't handle anything bigger than a 7" blade in this style.

My owners manual states 200mm blades but I can see the advantage of staying smaller when power is a factor.

My book does not list part numbers for anything nor any other important specs.
Are the arbors all the same size on these blades?
I see I will also need an adapter kit to mount the blade, I imagine these are model specific. The book is of no help here either.
I see mention of a limit stop in my book but the illustration is poor. It looks like a smaller deflector? There must be more to it.

I see a trip to the dealer is in my future.

 

[Bill G]

My owners manual states 200mm blades but I can see the advantage of staying smaller when power is a factor.

My book does not list part numbers for anything nor any other important specs.
Are the arbors all the same size on these blades?
I see I will also need an adapter kit to mount the blade, I imagine these are model specific. The book is of no help here either.
I see mention of a limit stop in my book but the illustration is poor. It looks like a smaller deflector? There must be more to it.

I see a trip to the dealer is in my future.

When you run a big blade on a underpowered trimmer it will be ineffective. It is no different then putting a 36" bar on a 026. Keep the RPM up with a smaller blade.

 

[hacskaroly]

The 3 blade deal looks like they could be sharpened

You are correct, the tri-blade brush cutter can be sharpened, the back side of the package it comes in has a sharpening guide which will help you to keep the cutter balanced as you sharpen.

You will be looking for blades which have a 25.4 mm arbor, the smaller 20 mm arbors will not fit and are meant for the FS 311 and up.

Stihl states that the approved blades for the FS 91R include the Grass-8 (4001 713 3803) and the Brush Knife (tri-blade) -250 mm (4112 713 4100). If you have the FS 91bike handle setup with the double strap harness and the limit stop, then the Scratcher-200 mm (112 713 4201) and Chisel-200 mm (4112 713 4203) are approved.

I see I will also need an adapter kit to mount the blade, I imagine these are model specific

No, the rider plate, washer (sometimes set in the rider plate) and the nut are not unit specific and will fit all trimmers FS 56 through FS 131. Sometimes you can get a kit with just these three things, other times they will also come with a deflector plate and a barrier bar. These kits usually average between $30 and $36 USD.

 

[JRM]

Stihl states that the approved blades for the FS 91R include the Grass-8 (4001 713 3803) and the Brush Knife (tri-blade) -250 mm (4112 713 4100). If you have the FS 91bike handle setup with the double strap harness and the limit stop, then the Scratcher-200 mm (112 713 4201) and Chisel-200 mm (4112 713 4203) are approved.

All GREAT info, thank you!
Can you explain to me what the limit stop is? In my book it just looks like a different deflector but the illustration does not show the greatest detail.

Am I correct in assuming they recommend the bike handle model only for the scratcher and chisel blades for greater control?

 

[Oletrapper]

I'm looking at a blade for my fs91r to be able to cut heavier weeds/brush than a line trimmer can handle. I see some different designs from a 3 blade to something resembling a circular saw blade. The 3 blade deal looks like they could be sharpened but I question the effectiveness of the cut without bogging the machine down. It looks like they could potentially get wrapped up in the weeds. What works best for you?
Thanks!

I run an FS 95. Oldie but goodie. My preference is the 3 blade polycut head. It uses 3 nylon blades which are replaceable. Takes out weeds and small brush (1/4" or less) effortlessly. For larger brush, I use the circular saw blade scratcher tooth, which is mounted backwards and drags rather than cuts through the brush.
https://www.ebay.com/itm/234549884825
Above is the stihl polycut .

https://www.stihlusa.com/products/t...ers/trimmer-heads-and-blades/circularscratch/Above is the stihl scratcher blade
Happy weed whacking. OT

 

[hacskaroly]

Can you explain to me what the limit stop is? In my book it just looks like a different deflector but the illustration does not show the greatest detail.

You are correct, the "limit stop" is the deflector. There are several different types depending on which trimmer head/blade you are using.

Usually when looking at the limit stop, they have representations of the different head/blade types and will have a circle with a slash through the ones you should not use with them. Typically the limit stop will be plastic for the auto-cut, poly-cut and grass/tri-blade brush blades, however when you start getting into the more menacing looking blades, there is a metal limit stop which can be used.

Am I correct in assuming they recommend the bike handle model only for the scratcher and chisel blades for greater control?

Yes, you are correct, especially when used with the "backpack" harness (comes with the FS 131, all others FS 56 - FS 131R come with the single strap harness), other wise you will need to purchase a separate backpack harness for about $75 - $85 USD depending on the size you nee (L, XL).

 

[fields_mj]

I'll give another vote for the Forester 9" blade with the chainsaw teeth. I've used it on everything from tall grass to 3" honeysuckle. On anything much under 2" across, it rips through it instantly.

 

[JD Guy]

In addition, the “limit stop” is designed so the cutter (circular blade) pulls the small saplings into the limit stop. Without this there is a significant chance that the blade will run right past the sapling and towards your leg or ankle.
Agree that a trip to your dealer is appropriate as the additional parts you will need cannot be sourced elsewhere, with the exception of your choice of cutter.

 

[JRM]

I'll give another vote for the Forester 9" blade with the chainsaw teeth. I've used it on everything from tall grass to 3" honeysuckle. On anything much under 2" across, it rips through it instantly.

I was looking at that one, interesting design. What sized machine do you have?

 

[fields_mj]

I was looking at that one, interesting design. What sized machine do you have?

I have a 56 FS. It's a little small for that blade, but if I keep the rpms up, it will handle it. Ideally, it would be best to having something noticably bigger than 30cc. 2" brush is no problem for it, it just takes a second or two to recover. On stuff that's 1" and under, the machine doesn't really acknowledge that it hit anything. My older brush blade is a Stihl, and I think it has 5 points on it. No comparison between them. My Stihl brush blade will cut tall thick grass and briars, but it has to work on a sapling for at least a few seconds. The Forester blade cuts through tall grass, weeds, briars, and saplings like they aren't even there. The only negative to the Forester blade is that it doesn't evacuate the cut grass worth a darn. If I'm going through thick tall grass with it, I use it like a scythe and make long swipes letting the grass/weeds fall over and lay flat and then go back for another swipe.