On my sawmill I have a boom loader which is motorized to slide in and out. To achieve this, I put a 3/4" threaded rod into a sprocket with 3/4" hole. It was a sloppy fit so I wrapped it with shimstock to tighten the fit, drilled a hole thru the assembly and drove a roll pin thru it. It was makeshit at best and doesn't turn true. I want to redo it with a 5/8" Acme rod (because I have it and 3/4" is gross overkill for this application) but need advice on fastening the rod to the sprocket short of taking it to a machine shop. I have scoured McMaster for Acme fittings and couplings but came up short. Any neat and clever ideas from the top?
Attach shaft to a sprocket
- Thread starter MillWeld
- Start date
over the last couple years i've dragged home a 20-or-so year old mill/drill and a 70 year old lathe. while i'm not a machinist, it's hard to get out of the mindset of turning or boring something in a case like this.
an acme rod is basically the same as a threaded rod, but with more square cut threads, so you're in the same situation. i can't visualize the entire application of this setup, but how about this:
mcmaster must have sleeves in that size? how about getting a 3/4 outside diameter and a 5/8 inside diameter sleeve. cut the sleeve to match the thickness of the sprocket, then drill and pin it all like before. to stabilize and minimize wobble, get a locking collar with a set screw for each side. short of resorting to machine shop tools, i don't know how to do anything different.
an acme rod is basically the same as a threaded rod, but with more square cut threads, so you're in the same situation. i can't visualize the entire application of this setup, but how about this:
mcmaster must have sleeves in that size? how about getting a 3/4 outside diameter and a 5/8 inside diameter sleeve. cut the sleeve to match the thickness of the sprocket, then drill and pin it all like before. to stabilize and minimize wobble, get a locking collar with a set screw for each side. short of resorting to machine shop tools, i don't know how to do anything different.
SandburRanch
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Does MillWeld have a welder? As mentioned fit it with a bushing but then weld it after you have laid the acme rod in an angle iron and rotate to check for sprocket face and rim run out. If the bushing is too loose to maintain alignment it can be tightened both on the shaft and in the sprocket by doing a 3 row equidistant sharp center punch knurl.
Kernopelli
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Without knowing what kind of sprocket you need I was thinking you might be able to use a standard sprocket hub and tap it for the appropriate acme thread and size. They do generally have a groove for keystock which would complicate the tapping process but not make it impossible with a little imagination. Surplus Center has examples of hubs and sprockets like I am referring to but these hubs are available at many farm supply stores and the sprockets are available to weld on separately.....I've used them many times. Or You could simply use the hub w/o tapping it and use collars on each side to ensure a tight fit etc.
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