clinton Posted January 7, 2012 Share Posted January 7, 2012 I have a Commonsense power hammer that I got running a couple of years ago. When I got it it had no motor and was removed for a barn that was tore down. I got the hammer running and at that time I knew the bearings were shot, but my theory is to use what you have if it works why mess with it. I planned on re-pouring the bearings further on down the road. So here I am further on down the road and i am planning to take care of this repair now and hope that the hammer will hit harder afterwards. So I have a few questions to address before I order the babbitt. How much babbitt do I need? I was on the Little Giant web site and it shows that you need 5 ingots of 4 1/2 lbs for a 50 lb Little Giant = 22.5 lbs if you use all new material. This seems like a lot of material to me. My bearings measure 4 inches long with a 2 inch shaft. Sid's price seems ok on the material at $26.00 for 4 1/2 lb ingot = $5.77/ lb and you know that it is the right stuff for this application. I will be tearing down the hammer this week end and I plan on making a mandrel and collars next week so I may have more questions soon. Quote Link to comment Share on other sites More sharing options...
macbruce Posted January 7, 2012 Share Posted January 7, 2012 Take out the old babbit and weigh it, then get a bit more. You gotta have more than the original amount. Using the old babbit in the mix is ok..... Quote Link to comment Share on other sites More sharing options...
clinton Posted January 7, 2012 Author Share Posted January 7, 2012 I think that maybe 2 or 3 x the material may be a good starting point, there were chunks missing before I ran the hammer also one of the top caps is in two pieces and someone fit a saddle over it to hold in place. I will be repairing that before the bearing pour. Quote Link to comment Share on other sites More sharing options...
peacock Posted January 8, 2012 Share Posted January 8, 2012 I think the amount to pour a 50 LG also includes the clutch bearing which is a large bearing and you have to pour extra so you will have plenty to machine after the pour. I always melt out the old babbit save it and add 1 new ingot(about 4.5#) to it. you want to make sure you have plenty. after it's melted I put a little 20 mule team in it to clean up the dross from the old stuff it's easier to skim. Quote Link to comment Share on other sites More sharing options...
clinton Posted January 8, 2012 Author Share Posted January 8, 2012 Ok thanks peacock, I will be working on this in the coming week unless I find a paying job. Quote Link to comment Share on other sites More sharing options...
clinton Posted January 9, 2012 Author Share Posted January 9, 2012 I tore the hammer down yesterday so I could get a better idea of the current condition of the shaft and bearings. It looks like someone must have turned down the shaft on the rear bearing side it measures right at 1 1/2 inches, the front end is about 1 3/4 inches and does vary by .05 when measured at each side and middle. Also it looks like someone had a hard time removing the drive pulley, it has a couple of chunks missing- and looks like they fabricated a collar to help hold it together. So I am not too crazy about trying to remove it now in order to fit the shaft in my lathe. So now my question is- do I use this shaft as the mandrel or go ahead and make a mandrel like it? Will the .05 taper make a difference? I think it would wear in quickly and with the amount of slop it was running at before .05 seems like a small amount to worry about. Quote Link to comment Share on other sites More sharing options...
peacock Posted January 10, 2012 Share Posted January 10, 2012 If you want to fix this hammer the best you can, build a new shaft. Take good measurments of this shaft, then saw it off on each side of the crank plate and pulley, Center punch as close to the center of the shat as you can, then step drill out the old shaft. This the only safe way to remove the shaft without damage to the castings. With that done make a new shaft, use it as the mandrel for the bearing pour, then install the castings and put it together. You will never regret the extra work Quote Link to comment Share on other sites More sharing options...
clinton Posted January 10, 2012 Author Share Posted January 10, 2012 That sounds like a good option, the crank plate is already loose it will come off no problem. What type of material is best for the shaft? I will need to take it to a machine shop to have the key way cut I am not set up for that, but that should not cost too much Quote Link to comment Share on other sites More sharing options...
peacock Posted January 10, 2012 Share Posted January 10, 2012 I use cold rolled or stressproof shafting. Quote Link to comment Share on other sites More sharing options...
clinton Posted January 10, 2012 Author Share Posted January 10, 2012 Cold rolled should be easy to get, I have some 2 inch mystery metal that was the shaft from a roll down smoke door. I will check with my supplier on the cost of a piece of cold rolled, better to use a known steel if I am going to put the work into it. Quote Link to comment Share on other sites More sharing options...
Judson Yaggy Posted January 11, 2012 Share Posted January 11, 2012 Don't know if it's cheaper than a machine shop, but McMaster sells keyed and partially keyed shafts up to something like 1.75 or 2 inches. If I recall a hammer sized shaft is in the $100 range +/- Quote Link to comment Share on other sites More sharing options...
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