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locker support questions
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[B]Is there supposed to be almost no play in the locker support, needle roller and clamp plate assembly? There's a slight amount of play between my rollers and locker supports that I notice with them off the saw. The black oxide finish is worn off the rollers at the contact areas, but they don't seem scored using the fingernail test. I'm not sure whether the rollers are harder steel than the supports, but there's a very shallow groove worn in each of my clamp plates.
It might be possible to press a sintered bronze bushing into the support but it would be preferable to create a new locker support with more area to securely retain the bushing. Another possibility is using inexpensive drill rod of slightly greater diameter than the original needle roller and ream the original locker support for tight fit to the rod. It appears you could build up the locker support only in the area where it retains the needle roller, doubling its thickness and giving it more wear surface. Eg: spot/tig weld a same thickness "patch" over the locker support needle roller hole and drill/ream that out to a tight fit with the original needle roller. If excessive play should develop in the future, replacement with a slightly larger drill rod should yield double the wear life. -
Originally posted by I saw that!The needle roller number changed when Ryobi made the switch to non-countersunk locker supports and pan head screws. Both early flat head screws and later pan head screws are 10-24 x 5/8" size.
It makes me wonder what about the roller changed -- material hardness, perhaps?
I may act as volunteer guinea pig since the replacement parts aren't very expensive. If so, I'll post my findings here.
I haven't disassembled the pin/support for examination but from what I can see the support is stamped sheet and I fear the pin hole was created in the same stamping operation. Dowel pins are hardened, ground, precision components intended to be press fit seated in a hole reamed to exact size. I'd hazard Ryobi sized the support hole for use as it exits the stamping operation without further machining, which would push the error preference to an oversized pin hole.
In any case an oversize locker support hole can be resized after slight buildup via hard solder, brazing, or attachment of an patch. Another possibility is peening the area around the locker support hole slightly and uniformly on both sides of the support which will close up the hole for finish sizing. Hardened dowel pins are quite inexpensive. A quick check found a box of 100 0.25" x 0.75" precision ground pins for under $14.
I should be able to simply flip my clamp plates over to the virgin sides, which will take care of play due to the worn grooves. Alternatively, I could use thin shim stock between the plates and rollers. So, I'm not too concerned about new plate availability after all.
I don't want to do too much removal/reinsertion of screws on this saw, though. The screws are the self-tapping variety and about the last thing I need is stripped or badly worn hole threads in the aluminum.Comment
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Originally posted by I saw that!My plate screws had worked loose, allowing the rollers to rotate against the plates and table pocket, thereby digging into them.
Correct, but early supports have machined countersunk holes. This is probably one reason Ryobi switched to regular holes and pan head screws. The supports could then be stamped in one operation with one jig in one configuration = quicker, cheaper.
The supports are inexpensive, too. Repair operations on the supports wouldn't be worthwhile to me, as I can get a set of new supports plus rollers for a few bucks total -- far less than the labor value involved in repair.
It may all be moot anyway. Having examined the parts and test fit them, I'm much less concerned about excessive play. As it turns out, the play I felt at the support joint was basically lateral (orbital?) wiggle (not the term I'm looking for, but I can't think of it right now, hopefully it makes sense); I didn't have the parts held in place as their normal operation would have them.
There's almost no play when trying to move the rollers exactly perpendicular to the support holes, and there appears to be no ovalness of the holes.
Also, although the roller wear as shown in the pics is extremely mild (seems to be only the black finish rubbed off), the roller can simply be reversed if desired, with the "fresh" end in the support hole. That does nothing for hole wear, but it could help reduce play a little, if need be.
I don't generally use anaerobics unless I'm certain I won't be touching that fastener again for a very long time, if ever. Gunked up threads can be a royal PITA to clean and sometimes even to break free w/o causing damage.
In this particular case, I may upgrade to the 15A motor at some point and even though I'd normally opt for lockwashers, the fact that the clamp plates float pretty much demands Loctite in the bosses.Comment
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Originally posted by I saw that!I don't have the supports (yet), but I'll go out on a limb and give Ryobi the benefit of the doubt and assume they punched them pretty closely to the diameter of the screws. If they're off a little, the errors should be rectifiable via parallelism adjustment of miter base, rip fence and miter slot table (if installed).
the amount of play is very low, even on these old supports. So yes, machining of the holes would have tightened up the roller contact across the length of the hole, as there'd be no secondary shear/fracture, but as you said it would have cost more.
The secondary slide arm functions just to prevent vertical motion of the locker support under vibration and essentially carries no significant weight. It needs only to be snugged to remove joint play. I'd fabricate it from brass sheet and should it loosen due to wear, it can be trivially readjusted. But given the fix and a coat of a MoS2 lubricant on the dowel pins they are likely no longer a maintenance concern.Attached FilesComment
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Originally posted by I saw that!Before the play compensator slide, I'd sooner do as you suggested earlier and just enlarge the roller/pin hole, reducing the new, larger roller on the end that belongs in the main table pocket. If you're into machining, you probably already have various sizes of bar/rod in inventory and a metal lathe. This would seem a little less work than the slide.
The minuscule amount present in my components should be eliminated as soon as the blade contacts the workpiece. The locker bracket should be thrust up and back, securing the [seemingly unworn] support hole firmly against the roller. There should be no wander or vibration (due to these particular components) during actual cutting operations.
In the cabinet saw patient, I measured via dial indicator the play in the locker support around the pins and see about 5mils of lateral movement. While I'll likely zero that out, I did observe flex in the locker bracket casting less than this play but still more than I'd anticipated. After the saw is reassembled I'll make static measurements to determine how significant the error contribution is.Comment
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