Alaric

Champion #1 Power Hammer Dimensions

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Many places will require one of their own pattern makers to do any patterns they cast to be sure that shrinkage and drafting is taken into account.

 

Secondly can the bearing cap be made from Bronze?  You should be able to handle casting that at home!

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I talked to the owner of the Foundry and he would prefer they made the pattern but was willing to use one I made if it passed their inspection. The cost for them to make it was in the $750 to $1000 range while casting the caps was approximately $75.00 each.

 

I didn't think of bronze, I would think it would be strong enough, with all the work being the lifting of the Tup and the low RPM I would think Oak would be strong enough, the majority of the load should be carried by the lower bearings. Would you still use Babbitt or use the bronze as a bearing surface?

 

I like the Bronze Idea, I get to pick up a new skill, can anyone think of a problem with bronze bearing caps?

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G'day,

 

I've measured up the bearing cap - they are both the same - and once I have them drawn more neatly, will post the drawings and some images to go with them. A day or two, depending on the weather... If it rains, sooner, it not, later...

 

Now, were I to do this job again, and be, as you note, not fussed about massive, I would be line-boring the main shaft bearings with the caps bolted into place and then fitting bronze bushes, NOT going to all the trouble of pouring and finishing new white-metal bearings. A far better result and far more easily serviced in future, should the need arise.

 

That noted, if you are confident in casting bronze I should expect it to handle to job quite well, if done properly and with a reasonably strong alloy. The female part of the pitman shaft assembly in these hammers is cast from bronze and it sees plenty of energy transferred through it, as well as shock loading. The catch, if it is one, is the entire cap would then need to be redone once the bearing surface deteriorated to the point excess clearance was causing a nuisance. That's assuming you are making the entire cap act as a bearing and not making a bush to fit into the bronze cap. This would leave you making - probably white-metal I'd guess - the bottom bearing shells after pouring them in situ anyway.

 

The quoted cost of the pattern making is pretty high compared against the cost of just two caps, but as we all know, casting is a process where many items are made from one pattern, which is where the economy of mass production comes into play. If you pattern passes muster, I'd probably go with the caps cast in iron then white-metal those... But have a think about line-boring, if you have the equipment...

 

The bearing caps do get a bit of reversing load applied to them - the rear cap gets upward force when the tup is being lifted and the front cap then see the majority of the reaction load, the rear one the minority, as the tup strikes the work, both in an upward direction also. The pedestals of the main frame see bearing forces at opposite positions of the tup, as well as the slow-speed vertical dynamic loads and rotational loads whilst the machine is rotating but not striking a workpiece.

 

If you were going to use oak as the caps and hence the upper bearing material - just for argument's sake - I think you could get that to work quite well. So long as you back it up with say a 1" thick steel flat bar backing piece to avoid the possibility of the oak splitting and letting go of the main shaft. Certainly makes for a simple shape; a rectangle with a half-round midway in one long edge, easily replaced and if kept greased, slippery enough to not present a large amount of friction. It would need to be shimmed so that the excess play can be allowed for as this sort of bearing seats and then wears though. After all, oak isn't going to permit close machining or hand-finishing tolerances as expected from metals. There were plenty of simple, low capacity bearings like this used in the past... Still leaves you to deal with the bottom bearing halves. Or perhaps these are still in your hammer and are good enough to use? If so, please let us know.

 

Regards

Jim Deering

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Wood bearings are still available. The grain is perpendicular to the shaft so the oil will wick through the grain.

What about fabbing up some caps, or just machining a set from a block? A lot less expensive than casting just 2 of them.

I was thinking about bushings for the one I am getting since they could easily be replaced down the road.

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I was being a bit facetious when I mentioned making the caps from oak, my point being these aren't caps for a big V8. I hadn't thought of using the Bronze as the bearing just as a medium to cast them from and I had considered just machining them from bar stock and still may. I'll probably go with having them cast if I can workout the details for 2 reasons learning to make the pattern and making connections in the Foundry world gives me another resource to call on for future projects and I have a tendency to try and put all the things I restore back to as close to original condition as I can. I'm not really set up to be able to line bore the bearings, just machining out the anvil area is going to require some creativity.

 

Thank for all this information, it's a huge help.

 

Now I just need to find time to actualy work on it.

 

Richard

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G'day,

 

Yes, well... Could still use oak, but I'd been wondering why anyone would bother, frankly.

 

I roughed out the deepening of the lower die seat in my hammer (-3mm to make back to square and flat) with an angle grinder. Then, using a gauge I had a mate machine up for me, set about reforming the dovetails and seating area for the die using hand tools. I'd previously welded up the fretted areas and, after a fair bit of work, it all fitted together quite well.

 

Just saying though, line bored and bushed is a lot easier to get everything true, which makes for a better-performing hammer.

 

I haven't had time to get those images and sketches but I haven't forgotten the offer was made either so the info will appear...

 

Regards

Jim Deering

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I plan on making sure everything is true, My machine tool equipment and skills put me in a pretty good position to do that. I've got a plane in my head for a jig that will allow me to accurately alien the shaft and hold it in place while I pore the Babbitt around it for the lower bearings.

 

No big rush on the drawings as I only have time at the moment to pick at this project.

 

 

Thanks,

 

Richard

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I finally found some time to get setup to machine out the lower dovetail area, It’s slow going as the cuts need to be very light since the only thing holding the hammer casting in place is gravity.

Here are a couple of pictures of the cuts in progress.

 

 

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