PDA

View Full Version : advice needed - drilling out to insert a bearing



dockterj
05-23-2008, 02:44 PM
I'm helping a friend work on his JD140 garden tractor. The spindles are 1" but the bores in the front axle are worn oversize and sloppy. There are no bearings so I thought I could bore them oversize and insert sleeve bearings. Was wondering if 1-1/8" bearings would be too thin for this? But my real question is this - guess I was taking too long so my friend asked the machine shop that did the engine what they thought and they said drilling would be fine??? I didn't think a drilled hole would be round enough, straight enough, or close to the right size. Am I nuts? I don't think my sherline can handle this but maybe it can if I take light cuts - otherwise could I use one of those expanding hand reamers?

SGW
05-23-2008, 03:05 PM
Given that you'd be trying to drill out an oval hole, I'd be dubious about drilling too. In addition to the concerns you list, there would also be the problem of accurately locating the hole. Of course you'll have that problem if you bore the hole too, but at least then it will be where you choose to put it, not where it just happens to end up.

dp
05-23-2008, 04:49 PM
Take a trip to the local Harley dealership and ask to see a front wheel bearing from a late model touring bike. Sounds like it might be what you need.

J. Randall
05-23-2008, 11:08 PM
You don't need anything very high tech, or high precision for this application. I would drill or bore to get them as close as possible, and grab some sort of tough plastic and make my bushings from that. If you use something that is a little bit self lubricating, you won't have grease or oil attracting the grass and dirt. This would work for wheel or kingpin type bushing, or both. I thing bearings would be a little bit overkill.
James

Racerx
05-24-2008, 02:28 AM
Are you SURE that wheel doesn't have bearings? Are we talking about an old JD 140 and not a newer Home Depot POS? Most lawn tractors use greaseable bushings in the front wheels, usually some kind of sintered iron. I guarrantee an old JD 140 will have replaceable bushings. To replace them, simply reach through the middle of one bearing with a long punch and drive the other side out, hitting first one side, then the other. After you get new bushings from JD, drive those back in with a big hammer, using a socket or something as a driver.

wierdscience
05-24-2008, 07:55 AM
Most likely they will look something like this when you drive them out,if you have a Westernauto or Snapper dealer near you they will most likely have them,if not bore and sleeve away.

http://www.mfgsupply.com/m/c/9-7258.html?id=cDtKsDYu

dockterj
05-24-2008, 06:21 PM
Thanks for all the advise - yes this is an honest to god - 1/4" steel framed John Deere 140 (not the new "heavy duty 12 guage frame" big box models)! This is the bearing where the spindle goes through the axle, so I guess this is the kingpin, right? Early model 140s had 3/4" spindles and replacable bearings but the later models went to 1" spindles and no bearings. Some of the guys over at weekendfreedommachines.org have had the axles bored to take sleeves but most of them said "had a machine shop do it". I figure you could either bore it on a mill with a boring head (or line boring on the lathe) or drill and/or ream it. Seems like one of those expanding hand reamers might do the job but I've never used one so don't know how much (or how little) they can cut (couple of thous?) in a pass and also how badly the reamer would follow the egg shaped bore? Bearings are cheap enough that I'd probably just buy them as my scrap box doesn't have anything I could make into bearings. Looking at the stock bearings for where the axle mounts to frame I think 1 1/8" OD sleeves would be perfect.

jdunmyer
05-24-2008, 08:33 PM
When the bearings in my mower's guage wheels finally went to pieces, the hubs were all bell-mouthed. Turned out that I couldn't easily find replacement wheels, so I bored out the old hubs and welded in new ones, turned up from some pipe. Much heavier than original, and bored to take flanged bronze bushings from the local hardware store. Made new axles from some 3/4" rod, drilled for grease down through the center. Better than new now.

Did the boring on the B'Port with boring head. Found the original hub to be MUCH harder than I would have guessed.

spkrman15
05-24-2008, 10:01 PM
Personally, if you can, i would line bore them, insert a new bushing, make sure there are channels for the grease to go. You probably only need to drill where the greas fitting is.

Expandable reamers, in my exprience are fragile.

Rob :)

dockterj
05-24-2008, 11:34 PM
Cool Rob - that's what I was looking for. I'll see if I can cobble up something to line bore them - turns out i was wrong on the wall thickness and should probably look at 1 1/4" OD bearings. Need to make sure the axle won't be to thin then. Thanks for all the good info, guys!