[jakeru]

Can someone recommend to me a TIG rod or stick electrode, and recommended process (TIG or stick) to use for building-up, and/or hardfacing to restore and improve these old "Merry Tiller" rotor-tiller blades?

I think they started out with sharp, 90 degree edges, like the new ones pictured below, they just got the large radiuses worn in from decades of scraping against big rocks and through dirt.


The worst wear is the outer blades. The thickness of the steel blades at the trailing edge (where they are not worn down at all) is 1/4".

I have ready access to TIG, which can do stick as well (AC/DC), although I've never stick welded before. With a little bit more hassle, I can also use an oxy-acetylene outfit.

I've got some E70S6 TIG filler rod in hand, and some 309L stainless filler. Would stick be a better process for this besides TIG? I might have a few stick electrodes of some type for steel welding floating around somewhere, no idea what they are though, and never tried using them.

I was wondering about trying a hardfacing rod that might some grit of tungsten carbide in it, to keep the blades from wearing down again scraping against rocks. What processes besides O/A can be used to add hardfacing? I'm thinking maybe build up the tines with some "cheap" type of steel build-up material first, and then switching to some type of hardfacing for the outer edge layer; would this be a wise strategy.

These blades do occasionally hit on a really big rock in the ground bringing them to an abrupt hault, but there is a spring loaded V-belt clutch that in that cases limits the peak forces somewhat. Thanks for any guidance.

[GWD]

These tines aren't the worst I've seen. They have been worn to a radius but don't seem to be any shorter.

One choice, as you mentioned, is to weld on 4" chunks of 2" x 1/8" flat stock and then hardface the leading edge with Stoody 31 or something similar. The flat stock will stick out the backside a bit but it will just help till the soil if the engine has enough HP to run the larger blades through the ground. Mine were done with 7018 on a stick welder with the Stoody rod applied as the last step.

Another choice is to hardface the tines as they are. It will work fine. Just check them yearly and add hardfacing when necessary. Build-up is not really necessary as long as the full tine length is there. A couple of tractor PTO rototillers were done that way when new and the original shape is holding up fine. In fact, they need another application of hardfacing so thanks for the reminder.

The tungsten rods are insanely expensive and are more for wear than for impact (like against large rocks) so may not be best for the application. Others may know more about it.

[jakeru]

Just mixing up soft (non compacted, large rock free) soil, the current tines do indeed work fine, but the machine becomes a bear chewing through compacted soil with rocks, which I've been known to do with it.

The radius on the outer tines seems to cause the machine to "dart" sideways unexpectedly when it encounters a rock on either side of the outer tines. Restoring the more "sharp" edge would I have a feeling make it easier to keep the machine headed straight, and perhaps help it to better grab and flip out the rocks on the sides as well.

The other symptom that may also be happening from the worn edges, is that occasionally a rock gets flipped up from behind and can become lodged (stuck) between one of the inner tines and the chaincase. This might happen less if the tine had a less worn edge, as it wouldn't try and push the rock sideways into the chaincase as much.

I have a really old school, "Oxy acetylene welders handbook", (Copyright 1943 & 1960), which although has a whole chapter on hardfacing, it only references specific alloys of seemingly outdated "Haynes" brand names (Haynes alloys, Haynes Stellite, and Haystellite).

Thanks for the tip on Stoody 31! Found their catalog... reading about the different hardfacing options should keep me busy for a while I want to see if they offer a bare TIG rod version of this.
http://www.thermadyne.com/IM_Uploads/Do ... _Final.pdf

Also, you've got me thinking about welding on the metal plates idea... rather than doing the extensive build-up I'd otherwise need to do to restore the original shape. It would definitely be a lot quicker.

[GWD]

Building up those tines to original would not be my choice. It would take a lot of material, many days, be expensive, and would invariably end up being a grinding project afterward. Buying a new set of tines would be preferable.

Welding flat bar on the worn tines makes the tines look like paddles instead of diggers but it works well. They would definitely need to be hard faced. Two layers recommended. Stoody makes a good product. That plan would be the quickest, cheapest, and most efficient way to restore the tines. As mentioned, I've done it and it works fine in rocky soil (size of baseballs).

Stick welding would seem to be the applicable process to do the job since the tines wouldn't have to be cleaned up and the flat bar can be just slapped on with 6011 rod. That doesn't seem to be an option so maybe someone else can lend some thoughts.

O/A would heat the original tines quite a bit and since they are probably hardened it would affect that factor.

Not sure if new (or reconstructed) tines would kick sideways any less or would prevent the trapping of large rocks in the frame. It is doubtful.

[jakeru]

Thanks GWD! Got any pictures of your modified tines?

[GWD]

Thanks GWD! Got any pictures of your modified tines?

Give me a day or so.

[jakeru]

That'd be great. Thanks!

[GWD]

Here ya go:

[jakeru]

Thanks! You know what the say about a picture being worth a thousand words? It's true!

[dav]

I think you should stick weld it to hard face it all, although (im sorry) i forgot wich electrostick is best. and you should definetly start to learn to stick weld, thats will help you alot in the near future. i first learned to weld on a 7018 rod and it my favorite thing to use, let alone do. u can probably weld your hand to any surface with stick, its way more versatile...and cheap(er).
but those are all opinions and im no pro, sorta

[welder57]

i downloaded a hardfacing manual from lincoln which i found at this site. can't find the link but if you email me back i can send it as an attachment if you'd like
sdamico@rochester.rr.com

[jakeru]

Well the weather was very nice today, I got the urge to fix my 'tiller. I just did the outer tines, the ones that matter the most. The way they are worn, they would throw the tiller sideways when they hit rocks on the outer edges of the trench being 'tilled.

I used Tig, with a torch mounted on/off switch to control the heat for the build up operation. I just got down there and did the operation right on the ground. I melted on quite a few 3/32" E72S6 filler rods on this, and probably about 150psi or so from my argon tank. It was a little windy and I did this outside, so I used the big #8 cup I usually use for stainless, and tried keeping the tungsten not stuck very far out. It seemed to work well. Setting some downslope on the machine let me vary the heat pretty effectively with the torch switch by toggling it on/off to either grow or shrink the puddle as desired. By the last time, I totally had the hang of it. I figured out how to distort the puddle shape as it was freezing by where I would hold the filler in the puddle as it was freezing - I could persuade it, either left, right, or out.

I also fixed the broken end of the clutch cable, by building up solid loop of 309L stainless right onto the broken, frayed ends of the cable.

I gave it all a try and tilled up a good trench, and it worked great! If I get more time maybe I'll build up the worn inner tines next. The only real problem with them is, every so often a rock can get flipped up and out of the ground, and can get lodged between the worn inner tine surface and the crankcase, which locks up the tiller. Building up the worn tines rectangular shaped would put an end to that for good. Maybe I'll just call it good though.

I didn't do any hard facing, but this is definitely a big upgrade from the way it was before.

[jakeru]

Here are the "after repair" pics