I am starting a rebuild on a 25lb Little Giant trip hammer and need to build up the pivot holes on the toggle arms. I watched a few videos on the internet and one fellow drilled out the worn holes and pressed bronze bushings into the new holes. I would think that the bronze would not withstand the forces that will be generated by the hammer blows but just wondering if anyone has used this method?
I was planning on welding up the worn holes and then redrilling them back to the original size. Has anyone any tips on rebuilding a trip hammer, I talked to the people from little giant and there is a video on rebuilding that I was thinking of getting.
Thanks
kelly
The Little Giant folks would certainly be the ones to ask.
Why not just buy new toggle arms?
Karl B. Andersen
Journeyman Smith
I've rebuilt a number of LG hammers, using Bronze bushings.....and if done right, will make a LG hammer run like "a singer sewing machine!"
Here's the BIGGEST thing you have to understand/be away of when rebuilding any LG hammer. These hammers were INTENTIONALLY BUILT WITH "SLOP" IN THE DESIGN! This was with the knowledge of things expanding/contracting with heating/cooling, and also leaving room for lubricant.
IF you install bronze bushings, you have to leave "room" in all the bronze bushings. If there isn't enough "slop"/clearance, the hammer will "lock up" when you turn it on.
I've rebuilt a number of hammers, both 25 and 50lb models, and found that at least .015" clearance is needed between the bronze and the "pins", with .020" being ideal on 25lb models, and .020"-.030" on 50lb models..... if using chainsaw bar lube as lube for the hammer.
Whatever you do, when rebuilding a LG of any type, DO NOT use hardened pins or bolts to connect any parts!! The original pins where dead soft materiel, and were considered "sacrificial" parts. This was done so that the pins would wear, and not the part(s) they assembled. If you use hard pins or bolts to assemble original LG parts, the parts will quickly wear, and then you'll have to spend big bucks to replace the part(s), or have them fabricated.
It's along the same lines as using a forging hammer that is softer then the anvil.....a hammer is easy/cheap to repair replace, where an anvil is not..... likewise, soft assembly pins in an LG are the cheapest and easiest parts to replace....where as if you wreck major parts......
If done correctly, using the correct assembly parts/pins, bronze bushing will improve the operation of a LG hammer significantly, and provided it's kept lubed, will increase the hammers
longevity immensely. Just for an example.... I bronze bushed a new style 25lb hammer in 1989, and ran that hammer every day, until I sold it in 2006 to pay for my air hammer....and as far as I know, it's still going strong at a shop in Alaska.
Ed Caffrey, ABS MS
"The Montana Bladesmith"
www.CaffreyKnives.net
I tried to purchase a new front bearing cap from Little Giant but the hammer is from 1904 and they have very limited parts so I machined my own. It’s good to know that bronze bushings will work and I might try them. I have lots of work to do on it like pouring new Babbitt bearings so I will keep researching and bugging you guys as I go. Thanks for the information. Kelly
IF you do go the route of bronze bushing.....don't forget the fly wheel! It's the largest, and potentially the most difficult to replace, but it makes the most difference in an overhaul.
Ed Caffrey, ABS MS
"The Montana Bladesmith"
www.CaffreyKnives.net
I have poured Babbitt many years ago and I did a tinning process as it was a journal bearing. For those of you who poured It on a trip hammer before do I need to do the tinning process with this type of pour? The seats for the main shaft Babbitt on the hammer had holes drilled into the frame so the Babbitt could not turn with the shaft so I think I might not need to do the tinning process, any thoughts?
