DSC Posted January 25, 2021 Report Share Posted January 25, 2021 I'm having trouble with the wheel head of my Shimpo RK-8. There is a slight vertical wave in the wheel head that is quite noticeable when the wheel is running. I've taken off the wheel head, cleaned the axle and the underside of the wheel head. I've also used a metal square tool and a level to check the flatness of the wheel head and it seems totally flat. When the wheel head is on the wheel, I've levelled it and still I have a slight vertical wave when the wheel is in motion. The wave is better (almost none at all) in the centre and worsens at the edges. At the worst point, the wave is probably between 1-2mm, which is quite noticeable while throwing. Could it be that my wheel head is ever so slightly bent? I just can't understand why I can't see the bend with the square tool. I've also placed the wheel head facedown on my granite kitchen countertop and I couldn't notice any bend or wave; it seemed totally flat. Is there something I'm missing here?? Link to comment Share on other sites More sharing options...
neilestrick Posted January 25, 2021 Report Share Posted January 25, 2021 Is this a new situation that just showed up on an old wheel, or is the wheel new? If the wheel head is flat, then the problem is with the shaft or the fit of the wheel head onto the shaft. Take the wheel head off and see if the shaft is running true. Then give Shimpo a call. Link to comment Share on other sites More sharing options...
DSC Posted January 25, 2021 Author Report Share Posted January 25, 2021 1 hour ago, neilestrick said: Is this a new situation that just showed up on an old wheel, or is the wheel new? If the wheel head is flat, then the problem is with the shaft or the fit of the wheel head onto the shaft. Take the wheel head off and see if the shaft is running true. Then give Shimpo a call. Thanks, Neil. I bought this wheel (used) recently and the problem has always been there. The shaft seems to be running properly, as far as I can tell, and since the problem is a vertical wave in the wheel head, I can't figure out how it can be both level and flat but still have a wave once the machine is turning. I must be missing something... Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 25, 2021 Report Share Posted January 25, 2021 Just a thought: If the wheel head fits over a shaft then loosen it up and make sure it is squarely seated in the hole. Pretty hard to bend a shaft actually. Next likely possibility would be a worn bearing. The up and down motion would be due to the shaft and wheel not being perfectly true or perpendicular to each other in all directions. Link to comment Share on other sites More sharing options...
DSC Posted January 27, 2021 Author Report Share Posted January 27, 2021 18 hours ago, Bill Kielb said: Just a thought: If the wheel head fits over a shaft then loosen it up and make sure it is squarely seated in the hole. Pretty hard to bend a shaft actually. Next likely possibility would be a worn bearing. Thanks, Bill. I've taken the wheel head off, cleaned thoroughly underneath and around the shaft, and it seems to be seated squarely in the hole. Can you elaborate a bit on the worn bearing possibility? Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 27, 2021 Report Share Posted January 27, 2021 It would be great if you could post a little video so we can all see this. Anyway what comes to mind is the possibility the bearing is so worn that the wheel head can wobble slightly. If this was the case I believe with the wheel head stopped you could feel the excess movement by hand just gently moving the head in all directions. There really should be no movement or perceptible rocking. If it rocks a little then likely the bearing or even an outside chance the bearing mount is loose.. You certainly could confirm the up and down movement and be sure it is moving with any fixed object placed above the wheel while the head was rotating. Any fixed pointer with a small gap above the head should confirm this. We did have a person on the site with a similar issue and when she actually put a dial indicator on it it was only a few thousandths. Turned out her initial pointer moved up and down enough to exaggerate things a bit and the dial indicator with its sturdy stand revealed no real wobble. Couldn’t hurt to confirm this wobbles and a short video posted here would likely get better feedback. here is the post https://community.ceramicartsdaily.org/topic/22534-brand-new-laguna-pacific-wheel-head-not-true/?tab=comments#comment-182499 If you follow it backwards you will see the video with the initial makeshift pointer made the head look like it had a significant wobble and the dial indicator with its sturdy stand confirmed it was an illusion. Not saying that is your case but that much wobble in a bearing ought to be detectable by hand and I find it very unlikely that the shaft is bent but could be an outside possibility I guess. Her initial video https://youtu.be/8kSSl7pJXOk looked like a bit of a wobble for sure. Link to comment Share on other sites More sharing options...
Hulk Posted January 27, 2021 Report Share Posted January 27, 2021 OP, I'm curious too, please post a video clip! If the shaft runs true, perhaps the wheel head is bent? I'm not finding an image depicting the underside of the casting; if it is not made with thick webs (see Brent wheel heads...), a bend may be possible, given a heavy enough impact. If so, better the wheel head bends than the motor shaft, eh? Regarding the thread Bill linked (above), I had set up a little test, concluding: "Seven thousandths o' vertical runout, ya, that'd bother me. Try propping up your favourite bat with a seven thousandths wedge? Deal Breaker This piece of paper, folder over, is closer to eight thou..." The clip clearly indicated seven thousandths runout, which may not look like much as defined by the gap between the jaws of your calipers, however, it's a lot when under your hands, err, my hands, at the wheel (...set up and test for yourselves afore decrying!). Whilst I believe one could definitely get used to that much (even more) runout, I don't want to. Link to comment Share on other sites More sharing options...
DSC Posted January 28, 2021 Author Report Share Posted January 28, 2021 Thanks, all, for your help so far! Here are a couple photos and videos to try and help you see what I'm dealing with. As far as I can tell, the shaft is strong and not moving. The wheel head also seems totally flat (I've checked with a metal level, a metal square tool, and on my granite kitchen countertop). So... I'm still stumped. Any further ideas? video of moving shaft video of waving wheel head Link to comment Share on other sites More sharing options...
Hulk Posted January 28, 2021 Report Share Posted January 28, 2021 That's more than enough vertical runout to bug me! Looks like the shaft has a flat where the wheel head's set screw meets up. When the wheel head is set on the shaft and the set screw(s) not tight, how much play is there - does the wheel head sit firmly against that washer (supported by the split ring); can the wheel head be rocked at all? ...there should be a big washer that sits between the split ring and the wheel head; perhaps you do have the washer, as there is a greasy imprint against the bottom of the wheel head, ok. In the first vid clip, looks like the shaft isn't running out. Try touching somewhat against the top edge of the shaft as it is turning - no horizontal runout? With the big washer in place, down firmly against the split ring, does the washer run out (vertical) at all? In short, where's the trouble? Shaft, interface, wheel head casting. Is the shaft running perfectly true? Is the wheel head set square against the shaft: looking at the split ring and the big washer, are they firmly square, no vertical runout; looking at the top of the shaft, is there a burr, deformed bit, or somewhat that interferes with the wheel head's seating; how tight is the fit - is there any play when the wheel head is set down tight against the washer and set screw backed out? If the shaft does indeed run true, and that big washer is a firm and square base for the wheel head, then the fault should be in the casting - the surface not square with the hole. If you can get your hands on a wheel head from a matching Shimpo, a swap check could tell lots. If not, try setting the wheel head upside down on another (good) wheel (or a banding wheel) center it up and check how the hole looks when spinning - any runout? Good that the wheel head is flat; it appears to be in good shape, that is, not much wear. The casting seems beefy enough - I like the eight spokes. When the wheel head set screw tightened, is there any perceptible play - any direction - in the wheel head? After alla that, you may find a way to work with the runout - where you center up your clay without depending on the surface of the wheel head, then cut away the uncentered skirt of clay. And finally, you might be able to shim the wheel head level, else shim your bats level. Please do post back what you find... Link to comment Share on other sites More sharing options...
liambesaw Posted January 28, 2021 Report Share Posted January 28, 2021 Look down in the wheelhead hole to see if there's anything that would stop it from fully seating. The shaft itself looks like it's running true, although it looks like at the base of it the retention clip is cockeyed. I think the wheelhead just isn't fully seating. Make sure your hole is clear all the way to the bottom, that the clip isn't getting in the way, and if everything is kosher, try seating it with a mallet. Link to comment Share on other sites More sharing options...
Mark C. Posted January 28, 2021 Report Share Posted January 28, 2021 a RUBBER mallet. Link to comment Share on other sites More sharing options...
neilestrick Posted January 28, 2021 Report Share Posted January 28, 2021 The top of the shaft isn't flat. If there's any horizontal play between the shaft and the hole in the wheel head, when you tighten up the set screw it's going to kick it out of level. Based on what I'm seeing, I think it's definitely a case of it not seating properly. I think a couple well placed taps with a rubber dead blow could get it aligned. Tighten everything up, tap it, then retighten if needed. If it's a problem with the casting, like if the hole isn't perpendicular to the top of the wheel head, then that's a bigger problem, and a new wheel head may be in order. Link to comment Share on other sites More sharing options...
Hulk Posted January 28, 2021 Report Share Posted January 28, 2021 :| How's the depth of the hole in wheel head compare to the length of shaft from the top of the big washer to the top edge of the shaft? Can a piece of paper be firmly caught between the wheel head and the big washer? The wheel head is supported by the washer, which rides on the circlip. Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 28, 2021 Report Share Posted January 28, 2021 3 hours ago, DSC said: So... I'm still stumped. Any further ideas? Just an observation, I put on the noise canceling headphones and the bearing sounds horrific ....... if that is what I am hearing. And, like our former experience with this wobble your indicator bounces so I am at a point where a dial indicator might reveal this is really smaller than it appears. It does look annoying though, that’s for sure. If it’s really minor say .010 or less then wear and tear on the bearing and wheel head might be the answer which means R&R the bearing and possibly new wheel head. Personally at some point if the bearing is fine I might choose to mill out that small deflection. Don’t know if you have access to someone with machine shop services. Afterward you definitely would know the head to shaft relation is perfect. Link to comment Share on other sites More sharing options...
neilestrick Posted January 28, 2021 Report Share Posted January 28, 2021 It does sound horrible, but that's kind of normal for RK wheels! Link to comment Share on other sites More sharing options...
liambesaw Posted January 28, 2021 Report Share Posted January 28, 2021 Lol yeah that's true, mine sounds worse but it's not the bearings it's the ring cone drive parts Link to comment Share on other sites More sharing options...
neilestrick Posted January 28, 2021 Report Share Posted January 28, 2021 1 hour ago, liambesaw said: Lol yeah that's true, mine sounds worse but it's not the bearings it's the ring cone drive parts I've never seen a quiet RK. Shimpo has made the loudest wheels ever (RK) and the quietest wheels ever (Whisper). There's no middle ground with Shimpo! Link to comment Share on other sites More sharing options...
Algoessailing Posted January 30, 2021 Report Share Posted January 30, 2021 Mark the high spot with a grease marker as it is spinning, then remove the wheel, turn it 90 degrees and replace the wheel. Mark the high spot again. If it is a bent wheel, the marks will be in the same place. If they are not, it is shaft related Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 30, 2021 Report Share Posted January 30, 2021 1 hour ago, Algoessailing said: If it is a bent wheel, the marks will be in the same place Opposite place? Bent shaft, same place, bent wheel opposite place I believe. I am not sure he can rotate his wheel though it’s keyed I believe. Link to comment Share on other sites More sharing options...
liambesaw Posted January 30, 2021 Report Share Posted January 30, 2021 I just want to know if the percussive maintenance worked Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 30, 2021 Report Share Posted January 30, 2021 58 minutes ago, liambesaw said: I just want to know if the percussive maintenance worked For thousandths of an inch? Scary! Better mark the high spot accurately. Link to comment Share on other sites More sharing options...
liambesaw Posted January 30, 2021 Report Share Posted January 30, 2021 3 hours ago, Bill Kielb said: For thousandths of an inch? Scary! Better mark the high spot accurately. No for seating the wheelhead with a mallet instead of setting it on. My rk2 needs a few taps, the wheelhead sits pretty tight on the shaft, even though it's keyed. Link to comment Share on other sites More sharing options...
Algoessailing Posted January 30, 2021 Report Share Posted January 30, 2021 11 hours ago, Bill Kielb said: Opposite place? Bent shaft, same place, bent wheel opposite place I believe. I am not sure he can rotate his wheel though it’s keyed I believe. If the wheel head is bent, the high spot is in the wheel, so it will reveal itself in the same place no matter how it is mounted radially to the shaft. Picture gluing a nickel to it. If the shaft is bent, changing the wheel head radially will change where the marks are on the wheelhead. But if it is keyed, it won't work as you said. The photo above looks like a smooth bore in the wheel head bit I wasn't sure Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 30, 2021 Report Share Posted January 30, 2021 13 hours ago, Algoessailing said: Mark the high spot with a grease marker as it is spinning, then remove the wheel, turn it 90 degrees and replace the wheel. Mark the high spot again. If it is a bent wheel, the marks will be in the same place. If they are not, it is shaft related 46 minutes ago, Algoessailing said: If the wheel head is bent, the high spot is in the wheel, so it will reveal itself in the same place no matter how it is mounted radially to the shaft. Picture gluing a nickel to it. If the shaft is bent, changing the wheel head radially will change where the marks are on the wheelhead. But if it is keyed, it won't work as you said. The photo above looks like a smooth bore in the wheel head bit I wasn't sure I get your point, spin the wheel both times and record the new high spot if it exists. The top quote was worded a bit static. Link to comment Share on other sites More sharing options...
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