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Tips on older Bush Hog attachments?

22K views 23 replies 10 participants last post by  Canary Al 
#1 ·
I am thinking about adding another Bush Hog [Brush Hawg, Bushwacker - whatever] attachment and was wondering what to look for [and what to avoid] in older 1950s/1960s/1970s-era units.

Are there some bad models that you want to steer away from, and, if so, then how do you recognize them?

Ultimately I would like to "mod" the unit, so that it would be able to take one of the really large saw blades.

Something like these:







Thanks!
 
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#19 · (Edited)
:howdy:
forgive the resurrection of this post, but I think the question I have relates to this posting pretty well...

Were there different Model 106 assemblies?
:dunno:

I seem to have one deck labeled 106 with a large Hex bolt topped fitting on top, slightly protruding... and another deck labeled 106 with a much more promonemtly protruding square bolt head topped fitting on top of the assembly...

The deck I have with the hex shaped top plug has the sloped shaped end attachments with the roller ball... came with the 450 project

Hopefully I can grab some photos this weekend to illustrate...

*edit* found online examples...

my first guess is that these variations indicate production run adjustments over time.... :fing32:
 

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#4 ·
The first Gravely 30" deck used a counter-clockwise drive that Gravely called a left rotary knife mower. The next ones were the 85-A, 185, and MA-601 (like the lower picture). These all share a common parts list. As far as I can tell, they are the same. Then came the MA-106. All of the drives after the 106 were made for the quick hitch.
 
#5 · (Edited)
The 30" Gravely 106 mowers have the strong, reliable, one piece casting W/6 bolt flange, that bolts the unit together.

Older 30" decks have only 4 bolts, seen in your lower pic, that hold a seperate gearbox lower plate to main casting AND deck, via threads in the casting. This design makes them dramatically weaker resulting in leaks & looseness from banging it up & vibration. Early 30" decks had a seperate top plate, you can see the unique retainer at top of the shaft spin & they spin backwards.

As to whether there are "some bad models" it depends on your goal/interest. If you're restoring an early 50's Gravely L one of the early 'spinning top' decks can be very good. For rugged use 106 & newer designs are best.
 
#8 ·
As I said "For rugged use 106 & newer designs are best." You know what a 106 looks like. The "newer designs" as arcam said "were made for the quick hitch" so you'd need a quick hitch adapter to run one.

I'm not sure all the newer ones were QH, but these decks look like flying saucers. Instead of simple vertical bolt on front & rear skirts w/welded sides, the housing is stamped in one big piece w/long sloping projections front & rear, to prevent things from being ejected.

The 106 is be the most common. IMO the much less common flying saucer would be kind of a shame to cut down to make a saw. No idea how the new gearbox compares w/106.
 
#9 ·
The 106 is be the most common. IMO the much less common flying saucer would be kind of a shame to cut down to make a saw. No idea how the new gearbox compares w/106.
The gearboxes newer than the 106 are not as good. They use grease instead of oil and their castings are not as beefy and they use blades with square holes that fit on shafts with flat spots on them which results in (the 2 decks that I had come across) internal gears with broken teeth. Your better off with traditional blades with round holes so if the blade has to spin it can and I agree with Dunbarmule that it would be a shame to cut up one of these decks being that they are not made anymore. - Kris :rauch10:
 
#16 ·
I know it looks terrifying & unsafe.
As I posted in the past, the 28" carbide blade I use is very controllable & smooth. Once you get all that Gravely steel between you & the blade & maKe sure nobody is in front of it, it's actually quite fun to use.
I've cut stumps, saplings, even plowed through some thick brambles & I feel very confidant in using it whenever needed.
Anyone who wants to add additional safety of guards & covers has my additional respect. I do after all make a portion of my living enforcing OSHA & EM-385 regulations on construction projects.







I have a Gravely 18" with it's dedicated obsolete gearbox, it looks cool hanging on the wall but I've never used it.
 
#18 ·
I know it looks terrifying & unsafe.
As I posted in the past, the 28" carbide blade I use is very controllable & smooth. Once you get all that Gravely steel between you & the blade & maKe sure nobody is in front of it, it's actually quite fun to use.
I've cut stumps, saplings, even plowed through some thick brambles & I feel very confidant in using it whenever needed.
Anyone who wants to add additional safety of guards & covers has my additional respect. I do after all make a portion of my living enforcing OSHA & EM-385 regulations on construction projects.


I have a Gravely 18" with it's dedicated obsolete gearbox, it looks cool hanging on the wall but I've never used it.
I too have one of the original saw blades and drives but instead will use the 28" saw on the 106 or QH drives. Deck will be modified to have a wedge cut out like in photo one of NBS's but with angle iron on top to reinforce the V. Plus if someone has to have an original unit, I can get another. Gravely sold the guards for the early and 106 drives as an option.
 
#21 ·
Thanks for posting the pic of that deck Canary Al, I was concerned there was something wrong with my deck, because I had to space the blade way up the shaft, similar to what your pic shows.

:fing32:

I would have thought the blade would be down close to the nut, to protect the nut. :dunno:
 
#23 ·
Those are actually blade height adjustment washers, you can adjust the blade height in 1/4" increments by how many of the washers are on one side of the blade or the other. Just make sure you leave one washer on the bottom. Probably good to leave at least one on top too.
 
#24 ·
Thanks for the ID Don. Now I'll have to be learning what that means. I'll be digging into this sometime this Fall. I definitely have some Bushing to do. So far my son in law has done it all with an L and a lefty deck that came with it. Best gift I ever gave him in my opinion. Ha Ha! At least from my perspective.

I worry that it might be somewhat unsafe (the lefty) so I saw this for a very friendly number and made a move. I plan to go over it carefully as i do most Gravely that I take in. That's why I jumped in on this thread.
 
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