Grapple Build, suggestions for bushings

[willysmb]

I am going to be building a grapple for my new tractor. When it comes to plate steel I have no problem. I have a CNC plasma table, welders, etc so building the actual grapple I have no problem with.

I have little experience with hydraulics but I have a good connection for that so I am just going to turn that over to a pro.

What I need some help with is suggestions for what I should do for bushings. Assuming I go with a typical tractor supply cylinder like the one listed below what should I do as far as bushings?



Cylinder
Grizzly Tie Rod Cylinder, 12 Stroke x 3 in. dia. - For Life Out Here

 

[KYErik]

Ask your local steel supplier about thick walled dimensional tubing. I used some for bushings for a project about 10 years ago. You can drill it and tap it for grease fittings. It was not cheap- I think it was about $15-20 per foot.

 

[willysmb]

I might be overthinking it. Lets say the bolt I am going to use that attached the top of the grapple to the bottom is 3/4". If I were to get a bronze/brass bushing with an ID of 3/4" and an OD of 1" and then press that into some 1.5" .250 wall DOM (1"ID) then would that work for my purposes?

 

[KYErik]

Yes- that is the most professional way to do it- but most heavy equipment uses greasable steel bushings.

If you were wanting to save some time and $, I would just use the 3/4" ID dimensional tubing for the 3/4" hinge pin, then drill/tap it for a grease zerk and use the plasma cutter to make a 1" diameter hole in the frame of the grapple then weld the dimensional tubing in place.

 

[Tractor Seabee]

I have used forged steel shaft couplings. Get the ones with no key-way. They are drilled and tapped for set screws which may work for zerks. Just cut to length needed. The wall thickness is roughly 1/4" so distortion from welding is minimal. I run an expandable reamer through them after welding. Line up is your biggest problem probably. A heating tip and 20 ton press helps there. I order them on Amazon. IMHO for the intended, use bronze bushings are an overkill and probably wear faster anyway due to the impact loads. I kave never seen them used on implements, only rotating shafts.

Ron

 

[GLyford]

If you happen to have round stock on hand, a drilled hole works too. While a lathe is easiest, if you use the pin to locate the bushing before welding it in, how centered it is in the stock doesn't matter as long as the pin is in the right spot when you are done.

There are a couple of thread sizes for zerks, I usually just use 1/4-28 (NF) ones because they are easy and I can find them everywhere, but if you have 1/8 pipe tap that works too.

If all the other zerks on the machine are metric (6-1mm, I think...?) matching those isn't a bad idea. But if they are BSPF I would stick to something easier to get.

 

[Shaneard]

I might be overthinking it. Lets say the bolt I am going to use that attached the top of the grapple to the bottom is 3/4". If I were to get a bronze/brass bushing with an ID of 3/4" and an OD of 1" and then press that into some 1.5" .250 wall DOM (1"ID) then would that work for my purposes?

That will work great but be prepared to ream the 3/4" bore out after pressing in/welding because with my experience with bronze/brass bushings they almost always close up after pressing in. It's hard to bore them out to the right size before pressing them in because you don't know how much they will close up.

 

[mike69440]

Search Results Shaft Collars Set Screw｜MISUMIMISUMI USA

Nice pieces, cheap.

 

[DuckSlayer1017]

Search Results Shaft Collars Set Screw｜MISUMIMISUMI USA

Nice pieces, cheap.

+1 for Misumi. Decent prices and you have lots of options.

 

[Tractor Seabee]

+1 for Misumi. Decent prices and you have lots of options.

I first looked at shaft collars. Shaft couplings are longer and have thicker walls. Most collars are less than 1/2 long. I googled shaft couplings and came up with many sources and settled on Amazon due to free shipping.

Ron