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Re: Cast iron gear

Originally Posted by OPUS FERRO

bcguide



What is the New-Purchase-Price of your machine . . . equipped
with the same Cast Iron drive-train . . . ?

Any OEM with a Boston Gear - you buy a new Boston Gear, and
it is new again . . .

You have received sage welding / brazing advice. I recommend
you execute [per spec.] - every welding/brazing techniques
posted . . .

This exercise is $ futile: but, will produce a wealth of welding
knowledge - that can only be gained - by doing something that
isn't worth doing . . .


Opus

Exactly like reading yet another opus post.🤣

Re: Cast iron gear

bcguide

Originally Posted by bcguide

. . . I have a cast iron pinion gear from a cement mixer . . .

What is the New-Purchase-Price of your machine . . . equipped
with the same Cast Iron drive-train . . . ?

Any OEM with a Boston Gear - you buy a new Boston Gear, and
it is new again . . .

You have received sage welding / brazing advice. I recommend
you execute [per spec.] - every welding/brazing techniques
posted . . .

This exercise is $ futile: but, will produce a wealth of welding
knowledge - that can only be gained - by doing something that
isn't worth doing . . .


Opus

Re: Cast iron gear

Attachment 1712002
Done, could have spend more time making it perfect but its good enough for this project.
Meltedmetal thanks for the heads up on using a soft metal.

Re: Cast iron gear

A corner or edge needs no preheat or post heat, or tooth in this case. Braze or nife55 which ever you are most comfortable with.
Good luck.
Peter

Re: Cast iron gear

Coming to the party late so if I missed something, please excuse me. Can you buy a stock gear from a company like Boston Gear that matches what you have and graft on to the shaft? Again, if this was covered already, I missed it and apologize.

Joe

Re: Cast iron gear

Yes to preheat, slow cool but doesn't need post heat and a carbide burr is the easiest way to clean up any carbon smearing from grinding.

Re: Cast iron gear

I hate to get into a thread late but in this case I feel I must. If you are going to melt the base metal of the cast iron preheat and post heat are needed. If you are going to braze it ( heat but not melt the base metal) heating is only needed until the brass flows aided by the flux if using O/A. Post heating is not needed, just cover the part and let it lay in an area where there is no air movement . The biggest mistake made when brazing is in the prep. If you grind the area to prep it you smear the carbon around and it makes the brass not want to flow into the casting. If you need to grind it out that is fine but the very last thing you need to do is take a carbide burr to the area to take off the carbon smeared layer of metal. This is true if O/A brazing or tig brazing.

Re: Cast iron gear

A few observations.
First one is partly pointless since I'm retired but when we were casting we used to keep at least 2 different sizes of cement mixer pinion gears in stock. They wear out and they are supposed to. You might inquire from the manufacturer or parts suppliers or maybe a local foundry if there is one around.
I wouldn't use something hard to rebuild the pinion gear, brazing is good. Consider the job of fixing the pinion gear versus rebuilding the crown gear.
If anyone has ever lubricated(grease/oil) the crown and pinion on your mixer, take him/her out behind the barn and have a serious conversation. It is meant to run dry, run it that way.

Re: Cast iron gear

Originally Posted by bcguide

never got to the shop today hope tomorrow works out better.
Rondo thanks for the offer but I need to get this fixed and mix some cement next week.
Smith door i would like to know how you would go about building a pinion. If I didn't hate string words together so much we could turn this into farmersam type thread. Let's see id make a dividing head the build a shaper have to go to town have a dinner out buy some 3/4 hss tool steel.... LOL.
I was serious though I would loke to know how you would go about making the pinion
Hope I didn't offend you Sam I really do admire your ability to fabricate stuff.

Your exactly right, most times you just need to get it working. You never really specified, is this a small mixer with an electric motor? If so you would be doing this on the bench. Fire up a charcoal grill and put it in the coals. Do your brazing then put it back in the coals , close the lid, cover if you can and let the fire burn out. Pre and post heat is not as important when brazing as when welding but it will make it much easier. Good luck with the repair.

Re: Cast iron gear

never got to the shop today hope tomorrow works out better.
Rondo thanks for the offer but I need to get this fixed and mix some cement next week.
Smith door i would like to know how you would go about building a pinion. If I didn't hate string words together so much we could turn this into farmersam type thread. Let's see id make a dividing head the build a shaper have to go to town have a dinner out buy some 3/4 hss tool steel.... LOL.
I was serious though I would loke to know how you would go about making the pinion
Hope I didn't offend you Sam I really do admire your ability to fabricate stuff.

Re: Cast iron gear

Yes, cast iron needs lots of preheat. I think around 800 deg's. if I recall but it's been a long time since I brazed cast iron in school. Look online, there are a few video's of brazing gear teeth. You can wrap it in a fire blanket when done or some guys bury cast in dry sand or Kitty litter to slow cool.

Re: Cast iron gear

What pre and post temps/time does cast need?
It does need pre heat no?

Re: Cast iron gear

A pinion I typically make new one out of steel.
The big gear is typically made cast too and pinion wear faster

Dave

Originally Posted by bcguide

I need help making a decision. I have a cast iron pinion gear from a cement mixer I want to build up the gear teeth.
This is what I have in my tool box, certanium 889, avesta 2311, I think it is rhe same as 304n , 308-16, 309 in tig rod and flux coated and gas brazing rod

My go to for cast has always been gas brazing , have not done any arc welding on cast is 25 years.
As I am trying to build up gear teeth and then grind and file to shape I think I would like a tougher and more work able surface then brass.
Thanks all
Scott

Re: Cast iron gear

Originally Posted by bcguide

I need help making a decision. I have a cast iron pinion gear from a cement mixer I want to build up the gear teeth.
This is what I have in my tool box, certanium 889, avesta 2311, I think it is rhe same as 304n , 308-16, 309 in tig rod and flux coated and gas brazing rod

My go to for cast has always been gas brazing , have not done any arc welding on cast is 25 years.
As I am trying to build up gear teeth and then grind and file to shape I think I would like a tougher and more work able surface then brass.
Thanks all
Scott

Many products will "work" for your gear. I like a product called Nickel Silver from Weldcote metals. Great brazing product for steel or cast. It's machinable and then it work hardens when put into service. Just a top notch product. How much build up do you have to do? Maybe I can send you a couple sticks.

Re: Cast iron gear

Well, it was just a thought.
Mike

Re: Cast iron gear

No I would have to grind down the hub and think it would be easier to build up the grear.
I'm going play with it this afternoon.

Re: Cast iron gear

Is there a chance you can shim the drum hub to move it closer to the pinion?
Mike

Re: Cast iron gear

Brass has the closest properties to cast iron except when high heat is introduced such as an exhaust manifold. Get a tiger torch or make a little furnace and braze it. Brass won't be too hard to grind and file to size and is the preferred way to repair cast iron in most cases.

Re: Cast iron gear

Its a cheap old monarch mixer with a crown gear on the tub and a exposed pinion.
I have done a spark and drill test it is cast iron.
I would be better of throwing it away and renting one for a couple of days but 1, it is a 100 mile round trip to rent one and 2. It would deprive me of the fun of fixing it

Re: Cast iron gear

Originally Posted by bcguide

I need help making a decision. I have a cast iron pinion gear from a cement mixer I want to build up the gear teeth.
This is what I have in my tool box, certanium 889, avesta 2311, I think it is rhe same as 304n , 308-16, 309 in tig rod and flux coated and gas brazing rod

My go to for cast has always been gas brazing , have not done any arc welding on cast is 25 years.
As I am trying to build up gear teeth and then grind and file to shape I think I would like a tougher and more work able surface then brass.
Thanks all
Scott

If you're comfortable with bronze brazing, I think it would be a good choice. The bronze would be easy to form and would match the cast iron in wear properties.

Re: Cast iron gear

Is this a differential pinion gear? That certainly isn't cast iron. If it's some other application possibly could be cast iron. Do a spark test to verify. If it is indeed cast iron, I would use 55 nickle rod. What's so bad about brass, that generally wears pretty well if it matches up profile wise and is kept well lubricated .

Cast iron gear

I need help making a decision. I have a cast iron pinion gear from a cement mixer I want to build up the gear teeth.
This is what I have in my tool box, certanium 889, avesta 2311, I think it is rhe same as 304n , 308-16, 309 in tig rod and flux coated and gas brazing rod

My go to for cast has always been gas brazing , have not done any arc welding on cast is 25 years.
As I am trying to build up gear teeth and then grind and file to shape I think I would like a tougher and more work able surface then brass.
Thanks all
Scott