560Dennis

Sharpen blades on Rotaty Cutter , How Sharp ?

Recommended Posts

Not sure if I can save the mower.

 how sharp do you resurface the blades ?  

About what angle should it cutter edge be ?  

Can you balence it ?  

 

Share this post


Link to post
Share on other sites

When at county we had a bench with a 4" x 2" channel iron bolted flat to bench and used a C-Clamp to hold blade down. Then used a 8-9" a disc grinder to sharpen blades that protruded to side of bench. A new blade will give U a guide for angle.... about 45*. I Ground blades sharp, but may depend what U R mowing with or without hidden objects. Never balanced   ,  j ust count grinder passes same for each pair of blades.

Share this post


Link to post
Share on other sites

I'll take some photos next time I'm out here here , I don't have a mfg name for it . It's old and honestly has a nice size gear box compared to the new ones. It takes the abuse I give it and I should put a slip clutch on it. 

 

Share this post


Link to post
Share on other sites

i'm guessing this is a bush hog ? My opinion is to make the blades sharp ! I would also say 30 - 40 something degrees also. another opinion i have is a sharp blade doesn't go through the whole machine but a dull blade will , meaning it takes more force to cut with dull blades. hope this helps 

                  Jason

Share this post


Link to post
Share on other sites

I would say we do ours about 30ish degrees. We make them fairly sharp. Not fillet knife sharp, but sharp. As long as you don't have a lot of rocks or the like it will cut almost like a finish mower.

Share this post


Link to post
Share on other sites

Sharper the better, like they said, downside is the sharp edge goes away quick when you hit stuff.  No bigger, sharpen again.  The idea of "balancing" a brush hog blade is kinda Rediculous, imo.   It's a 20some pound blade, that's  all wrapped up in what it's cutting.    shap, shift down, rev it up, and it will cut great. 

Share this post


Link to post
Share on other sites

I have built up the edges of the blades-----in particular the outer corners; (so to make the blade full length again) with my welder using several stringer type beads.  (6011 rod-----7018 better)

Then grind down to a relatively sharp edge.  Bottom of blade needs to be flat with angle/slope on top side.  

With worn corners--------strips of uncut or walked down grass begin to show up.

Good to look at new blade for pattern to work with.  Never have worried about balancing.

edit:  don't sharpen down to "knife sharp"------leave a little edge;  will help avoid chipping from rocks, stick,s, etc.

DD 

Share this post


Link to post
Share on other sites

I have thought about hardfacing mine with some rod I have.  Anyone done this?

Share this post


Link to post
Share on other sites
7 hours ago, Rawleigh99 said:

I have thought about hardfacing mine with some rod I have.  Anyone done this?

Hard surfacing would work but if you hit something hard , it could chip blade. Years ago you could buy hard surfaced or regular blades for Cub Cadet mower decks.

Share this post


Link to post
Share on other sites
18 hours ago, Rawleigh99 said:

I have thought about hardfacing mine with some rod I have.  Anyone done this?

I wonder how the metal of the blade you weld to would like it, I always thought blades  were a harden steel . Most harden steels when you weld on them the weld is hard but the metal next to the weld softens a little bit.  On really hard steels like cutting edges you can have the weld and base metal separate at the bond joint from different reactions to the heat. I think those hardened edge blades were heat treated to avoid delamination and other malfunctions.  Can anyone tell me more?

 

If if you try it let me know, I think it may be an interesting fix

 

11 hours ago, Rainman said:

Hard surfacing would work but if you hit something hard , it could chip blade. Years ago you could buy hard surfaced or regular blades for Cub Cadet mower decks.

Good point, they do make a couple different rods for hard facing with differing purposes, I wonder if an abrasion resistant hard facing would work better?  Like used in buckets and shovels?

Share this post


Link to post
Share on other sites

I have an opposition view on blade sharpening depending on what you are cutting.  I see the BUSH HOG as requiring a sledge hammer wood shattering blow to heavy brush and not a knife edge.  For long blade and edge life an edge around 3/16 at edge is fine. This is especially true if you are rocky terrain.  Also works well on tobacco, corn and cotton stalks.

A sharper edge can be tolerated on a good pasture weeds but even then a 1/16 edge is SHARP. Really sharp blades beat themselves to death in heavy use even on light weeds.

 

 

 

 

 

 

 

 

 

Share this post


Link to post
Share on other sites

Never have done any hard facing on Bush Hog blades-------but I don't see why it wouldn't work if applied correctly.  Adams Hardfacing from west Texas used to offer hardsurfaced blades for use on most all tillage implements.

In just building the blade up-----I did my welds and then cooled slightly with water------so to try not lose the temper in the blade.

I was concerned that the new edge might chip away from base metal------ but it worked out fine.  Sure don't want to get edge too thin-------or it will chip out as Oleman described.

Now-----I don't know about that sledge hammer edge.  I do know a dull axe will work you to death!!!!:o

I cut mostly grass and weeds------including my yard------so prefer a sharp blade for a better finish.

DD 

 

Share this post


Link to post
Share on other sites

My opinion, from personal experience sharpening rotary mower blades is a waste of time and effort. My 25 year old Farm King 6 foot rotary cuts just fine on dull blades. I think I might have sharpened them once in all those years and in no time I hit a rock which likely took off the edge. Still cut as good as ever. I can't see any difference in horsepower requirements or cutting ability. I've put a few dents in the sidewalls over the years from rocks flying off the blades but never had to fix or replace one. They are a swing back type blade. Dull as a hammer but somehow it leaves a nice even field behind itself. 

Share this post


Link to post
Share on other sites

I had mine resharp once . But it wasn't to an edge. My shop tech said he felt it shreds the left over brush stalk some it can't regrow quick . I said why not , I tried it in brush  and does shred , but I see replacement blades at tractor supply and they are sharp edged, so ❓for gras sharp  and for brush dull , what do you think about it ❓

Share this post


Link to post
Share on other sites

I ran a tree mower for seven years. The cutter head design was similar to the "bush hog" style of tow behind mowers. Just a lot bigger and heavier. Most of the time our new blades were un-sharpened, just flame cut to a square edge. We tried a flame cut bevel leaving about 3/16" leading edge (sharpening). Most of the time it was unnecessary as it took away wear material and reduced the weight (momentum) of the blade. The only time I think that sharpening was a benefit was when we were cutting a large amount of big willow or other hard to cut trees.

Share this post


Link to post
Share on other sites

Our hx15's blades were rounded off and it just laid the thicker ragweed over.  The ragweeds are real bad because the old man doesn't believe in spraying or burning pasture off.  Sharpened all the blades to a knife edge and it cuts soooo much better.  Sure they've rounded off some since but it's nothing a light touch up won't fix before I start again next year.  It shouldn't take 30 min a blade the next go around either since I'm not working with a rounded off cutting edge. 

Share this post


Link to post
Share on other sites

I guess this just goes to show it depends on your application: shredding versus cutting!  Lots of good responses, thanks!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now