The top shaft in my Little Giant trip hammer had some play in it that was causing the clutch pulley to hang up and not release fully. Also wanting to true up the shaft to add a band brake,and have it work properly,I decided to pour the babbets in the hammer sockets and caps.
The first thing to do is pull the hammer apart and thoroughly clean all parts and surfaces. Your objective is to melt the babbet out of the pockets to reuse it, and to be able to run a micrometer on the shaft to see where you stand on the condition of the shaft, as far as out of round or undersized.
If your shaft is close to standard(on a little giant 50lb.-the shaft should be 2″). You can rent the pouring mandrel,collars, laddle, shim blocks, spacers,babbetrite daming compound,chian and bungee, and finish gasket-shim set from Sid at little giant for a very small fee and shipping. You certainly can’t make it for that. If you happen to need babbit Sid also sells that in small easy to melt blocks.
When you find out the condition of your shaft, if it is out of round or undersized the nice thing about babbit is that you can place the shaft in a lathe and turn it till it’s true again and the babbits will pour to that size. You won’t be able to use Sid’s mandrel at this point but making a pouring shaft out of some turn, ground and polished, is an inexpensive solution to your situation.
If your shaft has to be replaced, be aware of the tapered keyways in the flywheel and spider. That means you have to push the part one way pull the keys then press it off. Measuring the keyways at both ends will tell you what to do.
Now that you know where you stand, and have some sort of plan, you are ready to begin.
Cleaning up the babbit areas before you melt the old babbit out is a good idea to keep less impurities in the babbit when your melting for your bearing pour. Melt out the babbit with a torch and protective clothing is required as this material will burn you.
The proper gear would be a respirator to protect you from Lead fumes, eye protection (preferably a full face shield), gloves (heavy or heat resistant), and some sort of leather apron in case of a spill. This material is heavy due to the lead content.
- Clean up all your surfaces with a wire brush or if you have a small sand blaster, that works well also.
- Flat file all the parting surfaces.
- Roll babbitrite into pencil size shapes( 3/8″ x 10″)
- Press babbitrite into recesses in collars.
- Assemble two inner collars on shaft.
- Place the shaft after you have put a coating of soot (from an oxy-acet torch, set real rich), onto the brass spacers — one in each cavity – (this centers the shaft up and down in the cavity). Left to right alignment is eyeballed. The soot on the shaft acts as a release agent for getting the shaft out of the babbit after the pour. Other products can be used such as white out, white shoe polish, or dykem. Soot is easiest to clean up on the shaft after, but the other products can be used on shims, matching surfaces, and collars, to make them release easier.
Use chain and bungee to hold shaft down to keep it from moving.
Slide inner collars into position-pressing Babbitrite against journal to form seal.
Install end collars — pressing to form seal.Use additional Babbitrite to make certain of good seal wherever needed.
Preheat to approximately 350-375 degrees (a good method to tell the temperature you are at, are tempil sticks which indicate the heat that they are labeled for). Keep the flame away from the babbitrite. It will harden and shrink away if allowed to get to hot — this causes it to leak.
Have babbit heating while preheating the journals. The babbit is hot when a pine stick held in it for 3-4 seconds comes out with a little brown scorch. Avoid Excessive Heating. Water and moisture will cause this molten metal to pop out with steam so your pot and laddle should not be dipped or used while wet or damp. The impurities can be skimmed off with a spoon or flatbar so the pour will be clean (just skim the surface). An old cast iron pan makes a good melting pot as long as it’s dry and not cracked.
Pour melted babbit into lower half of each bearing. Be sure to get it full / pouring as fast as you can safely? Don’t mess around. Allow it to cool for 10-15 minutes.
Remove shaft and collars from the machine.
Dress parting surfaces with flat file. Get babbit down,flush with cast iron.
Roll out more Babbitrite and press into collars again.
Install two center collars on shaft and soot up the shaft. Set the shaft back into the bottom bearing halves.
Install metal spacers (approximately 3/16″ thick) using a release agent on them.
Place bearing caps on top of spacers, and Install bolts, snugging them lightly. Check the ends to see if additional Babbitrite needs to be used at spacer area. If any places look like a possible leak a small amount of furnace cement can be wiped on to stop leaks also.
Tighten all the bolts.
Install the end collars / press all four collars against frame tightly to seal. Use additional Babbitrite to seal.
- Preheat caps only to approximately 350-375 degrees.
- Have babbit heating /check tempurature.
- Pour babbit in the top half through the oil holes. POUR QUICKLY.
- Allow to cool.
- Dress parting surfaces with a flat file.
- Dress bearing ends to flat and check end play in shaft file more if needed
Sid’s rental kit offers the collars that are all machined to give you the extra poured bosses for taking up end play in the shaft also allowing the clutch to work better.
Small folds and lines in bearing are acceptable.
Drill oil holes and cut oil grooves in the top half.
Clean and burnish bearing surface. (Scotchbrite pads work well) wiping in the direction that the shaft turns helps keep oil against shaft during break in. Dulling the very edges where the bearings come together helps to keep the sharp edges from wiping the oil from the shaft.It is a good idea when dulling the edges to stop 3/16 – 1/4″ from ends so as not to allow the oil to run out the ends of your bearings.
Oil and assemble.
Adjust bearings with shims — slight drag — no up and down play.
Readjust after 3 or 4 hours of operation.
Never allow to get loose enough to have any play up or down.
These directions should take some of the homework, preperation, and difficulty out of the repair of your trip hammer.
Author: Ralph Sproul – Bear Hill Blacksmith