Holes slightly oversize for the bushings

So these bearings are 3/4" OD and 1" deep? What is the ID? 1/2"? You could consider cross-drilling the 1/2" stock that goes through the bushing, and putting pins in there which would keep the bushing between the pins. Then who cares if things are a little loose? It's a swing set, not a Swiss watch!

You can monkey around with knurling the outside of the bushings. Maybe a better way would be to just epoxy them in. Again, this shouldn't be critical.

Grant

David Todtman wrote:

"David Todtman" wrote

Since you say they drop in "almost" all the way through, I assume that they are not loose, just not a press fit. Correct? If it is a close fit, you have a couple of options:

1. Use Loctite sleeve/bushing retainer to glue them in place. I don't recall the Loctite number for this product, but the color is green. It is a high-strength formula. However, I don't know if it will work on oil-impregnated bearings, so you may have to contact the manufacturer for guidance. I don't recommend this, but it may be the easiest option.
2. Drill and tap cross holes in your steel blocks and use set screws to lock the bushings in place. This would be my recommendation. You'll get the added advantage of being able to easily change out the bushings in the future if necessary. I would also put mating dimples in the bushings so the set screws lock positively (in the dimples), and perhaps use some medium strength Loctite (blue) on the set screws so they don't work themselves loose. Note: if you don't put mating dimples in the bushings and you have the set screws come up from the bottom (six o'clock), then the weight and action of swinging on the swing will bear directly on the setscrews and cause them to loosen.

If you do not have a close fit between the blocks and the bushings (i.e., the bushings are wobbly in the holes) then I would either make new steel blocks, or see if you can go to the next larger OD bushings.

I wouldn't. The grease will attract and hold dirt and grit that will get blown into the joint. The resulting mix of grease and grit will make a nice lapping compound to wear away the bushing. The reason for using oil-impregnated bushings is that they are self-lubricating. I would use them as is without additional grease or oil. If you want to get fancy, add rubber dust boots to keep dirt out.

Regards, Michael

An oil port tapped for a set screw would give you 2 features, holding the bushings in place and allowing you to oil them (at 30 day intervals, heh).

You might just want a friction fit without additional holes, so you could make the bushing dimensions change by slightly compressing them in a vise. Trying to compress them lengthwise will expand the OD slightly, and could cause the ID to become smaller at the same time, so you'd want to do this carefully, checking with a pin as you go.

I haven't seen grease work well with these kinds of bearings.. it's too stiff at low temperatures. Oil has always worked well for the applications I've encountered.

I really like this one, sad but true..

Reaming is better than drilling for bearings, you can generally expect a drilled hole to be too large.

WB ...........

First, thanks to all for the ideas. Good food for thought and somewhere in there is something I'll probably use.

this will sound really crude, but if you put some CA glue or the thick locktite in there and then drop in teh bushings they will stay - afterall, there's not much trying to push them out, is there? and, for your application why do you care if the bushing is a bit loose in the steel plate? it's a bearing whether it turns on the ID or the OD, and it's not a high precision high speed machine, it's a SWING afterall. Just use it as is

applications

Yep. Normal procedure is to drill undersize by 1/64" then ream.

In order for you to have succeeded with your project, it would have been wise to have double drilled your hole. By doing it that way, you could have avoided buying a reamer, an item with generally limited usage. Drill bits are terrible instruments in that they don't cut in the center (unless the point is split), they don't cut on size (usually), they don't drill straight (usually), and they don't drill round. By drilling in steps, some of these problems are minimized, especially the one where the drill cuts oversized. Had you drilled a pilot hole, then followed up with a drill either 1/64" or 1/32" under your desired size, then drilled size, you'd have a hole that MIGHT work for your bushing, certainly better than the ones you got.

If you do go the reamer route in the future, be advised that there are two types of reamers, chucking reamers and hand reamers. They are not the same and are not used the same way as one another. Hand reamers cut on the sides and are tapered, chucking reamers cut only on the chamfered end and are virtually straight, having only a few tenths taper smaller towards the shank to minimize seizing in the reamed hole. Hand reamers are not very user friendly, rarely providing a decent hole, and they don't respond well to being power driven. Chucking reamers are difficult to use by hand, and are not intended to be used that way. They do a reasonable job when power driven, but they, like twist drills, do not necessarily provide straight, round holes, though much better than twist drills provide. For pressing in bronze bushings, they work very well, though. That would be the ideal procedure if cost for tooling was no objective.

Your bronze bushings will be oversized, both internally and externally, and rely on properly sized holes to collapse them so the interior is the prescribed size. Using them in sloppy holes will leave the inside diameter well oversized, but as Grant observed, it's a swing, not a Swiss watch.. Oh yeah, knurling the busing would likely be a failure considering they are powder metallurgy, they are not solid objects. They would likely crumble, even if you could come up with a way to knurl them. Again, the bores would still be oversized that way, anyway.

Good luck!

Harold

David Todtman wrote: First, thanks to all for the ideas. Good food for thought and somewhere in there is something I'll probably use.(clip) ^^^^^^^^^ Actually, there are several usable ideas already submitted, but let me add a couple more. First, I suspect that if you just go ahead and assemble it as is, it will work. Most likely, the weight of the swing on the bushing will cause it to rock slightly, and wear into the roughness in the holes, and stay put.

A trick I have used for repairing the clutch pulleys on small offset presses: The pulley comes from the factory with a press-fit oilite bearing, which sometimes works loose and drifts out of its hole. In the field, to save the cost of a new pulley, and the down-time waiting for it, I would tap-drill into the Oilite/steel interface, and then tap of set-screws. Tnhreading a set-screw in, half in the Oilite and half in the steel will definitely prevent the bushing from drifting.

I think Loctite or CA glue would work perfectly well for you, and would be easier, but I just wanted to tell about my idea :-)

Hi,

I hate to be crude; but why not just use a center punch and stake them in place by 2 or 3 well place "pips" on each side?

This is a swing set, after all.

Jim Huds>I am making a set of swing hangers--the pendulum-like structures from which

Actually, I

sources can

Nope,wrong. This is !!!THE SWINGSET!!! Custom made to last a century or more. Next: take on American Chopper at their own game.

There have been a number of suggestions but I'll add these two: For next time, drill about 1/64" undersized and ream or bore to a few thou under then press in the bushings. Might even be worth buying an adjustable hand reamer. You will likely have future uses for it. Are you in the Vancouver area? There is (or used to be) an outfit on SW Marine drive that sells Oilite stock. When I needed some similar bushings I bought some 3/4"-1/2" stock to make them. The OD is significantly (not just a few thou) larger than 3/4 and the ID significantly smaller than 1/2. I machined and cut of my bushings from that.

Ted

Cannot you simply let a chain hang from an eyebolt? That system has worked for a few decades. I used to be a big time swinger and never had one break. It is a swing.

Someone must have been inspecting and maintaining those swings pretty well.

We suspend kid's swinging therapy equipment in a clinic, with steel carabiners hooked onto 5/8" diameter eyebolts, and it's amazing how fast things wear. One time someone brought in and used a piece of gear with an aluminum caribiner and IIRC it wore nearly through in a couple of weeks, no suprise.

We don't use any lube on 'em though, because I haven't yet found anything which doesn't grime up our therapist's hands and clothes when they swap pieces of equipment, which they do quite frequently.

When the suspension parts wear about 1/3 of the way through I swap 'em out and build up the worn places with MIG.

Jeff

Did not know you were building medical devices, Perhaps pillow blocks would work in this application. Mount them upside down and pass an axle thru the pairs. Hang chain from axle. FDA should approve. Kids should be able to swing really high without fear of breakage.