Green Tractor Talk banner

1 - 16 of 16 Posts

·
Registered
Joined
·
610 Posts
Discussion Starter #1 (Edited)
I'm getting my Gravely Promaster 100 ZTR ready to sell (since I have a new ZTrak) and I'm getting pretty anal about getting it in tip-top condition. I guess because it's fun and the old girl can have a long productive life with a new owner.

Anyway the front anti-scalp roller has had a bunch of slop in it for years and since I have the mower in the air on my 2 post vehicle lift I thought I might as well try to restore the roller as much as possible. I pulled the shaft and the contact point on the shaft and the bracket is very worn, you can see the groove worn in the shaft in the picture.

I measured the diameter of the old shaft and amazingly I found some round rod laying on my lathe the right diameter (~0.62") and even a little longer than I needed. The odds of that happening again are about zero, I was expecting to rummage around my steel stock for half an hour looking for a rod.

I really didn't need to chuck the rod in my lathe but it was a good excuse to play with it. I faced one end, cut to size, faced it then added a chamfer on both ends. A Scotchbrite abrasive pad made it nice and shiny. Then off the vertical mill to drill the holes on each end for the cotter key keepers. Using the mill's vise was much easier than trying to use a drill press for this small diameter rod. I used a centering drill and then drilled to size.

Now I have to figure out how to deal with the elongated holes on the bracket that holds the roller - it's easy to see how worn the holes are from the picture. I'm currently leaning toward adding fill with my TIG and then drilling to finished size. I thought about cutting those ears off and making new ones but that's a bunch of work. Another idea was to tack weld washers but they would eat into the shaft rather quickly.
 

Attachments

·
Premium Member
Joined
·
4,695 Posts
Very nice. Since you have a lathe I would drill the hole round, then machine a stepped bushing to fit the new hole and tack weld the step part of the bushing to the bracket in a couple spots.

At least you didn’t mention just welding the rod into the bracket. I had someone do that on something I bought.:laugh:
 

·
Registered
Joined
·
529 Posts
John, I'm with Herminator, bush it. If you have access to a reamer, drill & ream and install an oilite bushing. If one hole is higher/lower/more forward/more rearward from other hole, who cares! This is an anti-scalping roller and should not be touching the ground. If the roller ends up a little "cock-sided" it ain't gonna hurt! Bob
 

·
Registered
Joined
·
610 Posts
Discussion Starter #4
Woot!

Brilliant idea from the Herminator:bigbeer:.

Since I already had the shaft made I didn't want to machine a stepped bushing so I made them the thickness of the mounting bracket. I was considering making them from brass stock and somehow welding brass to steel but I've never done that and I'm not sure that's even possible so I made them from 1" steel round bar. I wanted to use the shop press to press a brass bushing in but due to the shape of the bracket I didn't think that wasn't possible (unfortunately.)

I think I'll use TIG process with no filler rod to melt the bracket to the bearing in three places - should do fine. I suppose I could drill a couple of holes in the joint between the bracket and bearing and use filler rod.

It would have been nice to have somehow improved the design - maybe with a real sealed bearing or even use bearing steel for the bearing material but I don't have any (I'll order some for shop stores.)

To my surprise, this has turned out really well and the new shaft and bearings line up really well. I never know what to expect when enlarging a hole, especially one that large. Tomorrow I'll TIG the bearings and put it back together. I felt the rear anti-scalp roller and it has a bit of slop but not enough to spend the time fixing. When I showed she who must be obeyed the shaft I machined she thought I was nuts for spending so much time on the roller since we're selling the Gravely.
 

Attachments

·
Premium Member
Joined
·
4,695 Posts
When I showed she who must be obeyed the shaft I machined she thought I was nuts for spending so much time on the roller since we're selling the Gravely.
Looks good but yes wives will think like that. However doing the little extra is why she is still your wife and the good Karma from the new owner might be just the little extra that gets you into heaven if it’s a close decision.

Nice lift. When I poured my shop floor I dug 4 trenches 6’ x 2” that would be a foot deep so I could put one of those in 2 places. I don’t have a lift but the concrete is still there.
 

·
Registered
Joined
·
610 Posts
Discussion Starter #6
I think you only need 5” of concrete for this particular Atlas lift - it is the 10,500 pound model. They aren’t that expensive and it’s a very useful piece of shop equipment for the DIY guy, once you have one it’s like why did I wait so long.
 

·
Registered
Joined
·
2,681 Posts
I was considering making them from brass stock and somehow welding brass to steel but I've never done that and I'm not sure that's even possible so
Yes it is possible but it isn't welding.

Welding is joining two like metals by melting the base material. However they have to have a similar composition and melting point which isn't the case when you are talking brass and steel.

Brazing is a method where you can join two similar or unlike base metals. The temps are much lower and the base metals are not melted. This is the technique you would use to join brass to steel.

There are pros and cons to each method. Which is why some processes could call for brazing two like materials that could have been welded. For instance, the lower temps reduces risk of thermal distortion of the base metal. It can also produce a cleaner finished product without the need for going back and grinding the

Is There A Difference Between Brazing And Welding?
 

·
Registered
Joined
·
610 Posts
Discussion Starter #8
Brazing - DOH! Of course, I don't know why I didn't think of that - I've brazed steel and brass before. I'm setup to do brazing, GTAW, GMAW and SMAW processes in the shop.

I had another DOH moment last night when I realized the shaft for the roller DOESN'T ROTATE :laugh: - it's captured so all of the bearing talk is superfluous.
 

·
Registered
Joined
·
529 Posts
John, Shaft DOES rotate! Maybe it's not supposed to...by design... but it rotates in use. Look at the pics of your shaft in your first post: heavy/deep wear marks where shaft turned in elongated holes that you bushed (from shaft wear).

Hmm, I can see brazing with GTAW or GMAW, but SMAW? I've never heard of a brazing rod used in a stick welder. Bob
 

·
Premium Member
Joined
·
7,883 Posts
John, I think you really bought a new mower so that you could tinker on / re-build the Toro. :kidw_truck_smiley:

No worries. I won't tell your wife. :lol:
 

·
Registered
Joined
·
2,681 Posts
John, Shaft DOES rotate! Maybe it's not supposed to...by design... but it rotates in use. Look at the pics of your shaft in your first post: heavy/deep wear marks where shaft turned in elongated holes that you bushed (from shaft wear).

Hmm, I can see brazing with GTAW or GMAW, but SMAW? I've never heard of a brazing rod used in a stick welder. Bob
I think he was just listing the type of welding he is equipped to do. Brazing is typically done with a Oxy/Acetylene torch. At least that is how I do it. You want to heat the base metals and use capillary action to pull the material being used for brazing into the joint. It can be done with an arc type welder but at least in the home setting most use a torch.
 

·
Registered
Joined
·
529 Posts
To me, brazing is like soldering, just a higher temperature and a different filler material. I don't think (??) there's any melting of base metals. Bob
 

·
Registered
Joined
·
610 Posts
Discussion Starter #13
John, Shaft DOES rotate! Maybe it's not supposed to...by design... but it rotates in use. Look at the pics of your shaft in your first post: heavy/deep wear marks where shaft turned in elongated holes that you bushed (from shaft wear).
The shaft is captured with a cotter key - a bolt in the eye of the key is bolted to the bracket. Through constant motion, the cotter key wore away some permitting some movement which led to other parts being able to move, etc. etc. It's not designed to move but it did over time. I think it's simply an inadequate design. Another problem is the height of the roller bracket is fixed to the deck - it can't be adjusted up and down.

Hmm, I can see brazing with GTAW or GMAW, but SMAW? I've never heard of a brazing rod used in a stick welder. Bob
sennister is correct - I braze with an oxy/acetylene torch. The other processes are the 'official' descriptions for MIG/TIG/stick welding processes (not necessarily in order.)
 

·
Registered
Joined
·
2,681 Posts
To me, brazing is like soldering, just a higher temperature and a different filler material. I don't think (??) there's any melting of base metals. Bob
That is correct. Then main difference is when welding the base metal is melted and when brazing it is not. The capillary action used when brazing and the process is very much like when doing copper plumbing work. I think the main difference is the filler and temps to a point but they are basically the same thing.

About the only time I am brazing is when I am trying to join two different base metals but technically they can be the same. When dealing with different base metals at different melting points you really can't weld them as you would just have a mess. That is where brazing comes in.

This explains the difference between soldiering and brazing pretty well. The biggest difference is as you pointed out. The filler material and because of that the melting point of the filler. Soldiering is normally lead, tin or other like alloys with a low melting point around 300c. Brazing uses copper tin zinc and alloys with a much higher melting point above 500c. That is why you soldier copper plumbing not braze it. The temps are too high and you would be melting the copper pipe. However the process is pretty similar.

What is the difference between brazing and soldering? - Quora
 

·
Registered
Joined
·
2,681 Posts
Also nice job with the lathe work. I have my dad's old Atlas 618 and I am always looking for an excuse to use it. He had gotten a newer Delta (I think) metal lathe and had the old Atlas sitting in the shed. One day I asked him about it and said he could just as easily store it in my "shed" aka shop.

It is fun to find an problem like that and figure out what it will take to fix it rather than run to the parts store all the time and take the easy way out.

I look at it as a way to justify having the shop.
 

·
Registered
Joined
·
610 Posts
Discussion Starter #16
Also nice job with the lathe work. I have my dad's old Atlas 618 and I am always looking for an excuse to use it. He had gotten a newer Delta (I think) metal lathe and had the old Atlas sitting in the shed. One day I asked him about it and said he could just as easily store it in my "shed" aka shop.

It is fun to find an problem like that and figure out what it will take to fix it rather than run to the parts store all the time and take the easy way out.

I look at it as a way to justify having the shop.
Thanks! I've had a lot of fun with the lathe, I have stamps for three suppressors and machined two, need to start the 5.56mm can. I learned a bunch with that project. I try to keep a variety of steel, stainless steel, brass and aluminum stocked for the odd project or repair, it's really come in handy. Out here I just can't make a ten minute run to the hardware store and it's more fun to make a part anyway.

Since I have a bit of time involved with making the bearing I thought I better make a test bearing and practice welding (TIG) it into a similar bracket. I found some steel the same thickness as the Gravely bracket, made a 1" hole and tried to just melt the bearing and the plate together with no filler rod but that was going to require way too much heat. So I added a little filler and that worked quite well. I haven't used the Miller TIG machine in months but I did an okay job after practicing on my test parts.

Too bad I don't have any Gravely red paint to paint the bracket (LOL.)
 

Attachments

1 - 16 of 16 Posts
Top