[tbk]

Hello all,

I've got an old concave and grate that I'm trying to make square again, lots of heating and lots of beating! It seems to be coming together about as good as I can hope for, but I'm wondering about a few things.

With all the heat and bending is the chrome hard surfacing pretty much shot? Would it be worth my while to run a bead of hard surfacing weld over top of each concave bar? Anybody have any experience doing what I'm trying to do?

Another question, I've been looking for parts to allow me to return tailings to the cylinder instead of just to the accelerator rolls. I've been searching salvage combines here in Michigan, but seems that was not an option most folks took. Can someone point me in the direction of someone that has such an item?

Thanks!

 

[evan]

Buy a new one Will pay for one in one season of cracking grain

 

[scott]

Concave is scrap, if accelerator rolls are doing there job, you should have very few tailings if machine is set right, Scott.

 

[tbk]

Sorry, why is the concave scrap?

 

[scott]

Unless you have a jig to straighten it, it will never be right, heating chrome you will loose chrome and concave will be soft, Scott.

 

[KWO]

If you weld a bead of hard surface on the wear surface ,the heat will pull the concave out of straight . Always weld underneath to straighten. Also with the heat you have used to straighten it will likely have caused the loss of Temper in the steel. It will be soft and back to where you started in no time

 

[tbk]

OK, so are you all telling me once a concave bar is bent it has to stay bent and the only fix is a new concave? I guess I figured the concave bars were mild steel and the hard surfacing gave the wear points durability. All that said, do concave rebuilders start with all new bars? I used heat to bring the "wobble" out of the bars so they were all roughly parallel. This was the concave grate.

 

[scott]

OK, so are you all telling me once a concave bar is bent it has to stay bent and the only fix is a new concave? I guess I figured the concave bars were mild steel and the hard surfacing gave the wear points durability. All that said, do concave rebuilders start with all new bars? I used heat to bring the "wobble" out of the bars so they were all roughly parallel. This was the concave grate.

Yes you are correct, problem being is chrome is gone after heating, I guess depends how beat up concave is, Scott.

 

[KWO]

OK, so are you all telling me once a concave bar is bent it has to stay bent and the only fix is a new concave.

No you can straighten things with a press but you can't use heat

 

[Deadeye]

Send it in to St. Johns Welding if it can be fixed they can do it and it will be straight.

 

[mavis]

I got my return to cylinder parts at Mike's Equipment in Buhler, Kansas, He had several N's and early R's to choose from. I don't know about R50's though.

 

[amos]

Take it to C Trimpe Inc. Seymor Indiana, they know more about concaves than we ever will...and they are less money than anybody else...not to mention their tungsten carbide hardening is the best

 

[tbk]

Well, here's the deal. After being told by EVERYBODY on here that heating my concave bars makes them junk, I resigned myself to new or rebuilt components. I called St. John's Welding and talked to THE MAN. Frankly, what he had to say contradicted everything I was told on here, and I'm guessing he knows what he's talking about.

First off, the concave bars are not tempered steel, they are mild steel (read soft).

Second, you can't put hard facing on tempered steel, it won't stick...gotta be mild steel

Third, they heat up bars all the time in an effort to straighten bent concave's.

Apparently, he was following this thread, and asked me if I was the guy with the problem. Long story short, just cuz somebody said so on the internet don't make it true!

I know all the responders had the best of intentions, but it's a little disheartening when a bunch of guys tell you your wrong. My assumption from the beginning was that it was mild steel since I could not envision any manufacturer using tempered, hard steel in an application that sees stones and other hard bits pass through them on occasion. I'd think they'd want the components to bend, not shatter under stress, wouldn't you?

Regardless, thanks for all the responses. I learned a lot more about this stuff than I
anticipated. This is a great site!