hfmann wrote:...There is a maintenance and troubleshooting section that goes through first "Balancing the Belt Tension" and then secondly "motor belt tensioning." In contrast to the manual, In Jim's video, the tensioning is done first, and then the balancing with the eccentric is done second. It take it you agree with Jim versus the manual. I do. There is no logical point to balancing unless it is done last.
Edma and David - even with the manual I don't get how to use a straightedge to "check that the face of the Motor Pulley is still aligned with the center of Poly-V Pulley on the Idlershaft." (And yes David - Jim didn't do that in the video) All I can tell is when I put a straightedge across the top of the motor pulley, the edge seems to squarely strike the lower part of the top pulley on the idler belt.
straightedge on pulley.jpg
My interpretation is that the side of the straight edge riding flat on the motor pulley should align to that ridge between the two belts in your picture. In other words, aligning the left edge (top edge in drill press position) of the motor pulley to the left edge of the motor belt portion of the idler pulley. This should give the perpindicular/parallel relationships that Edma referred to.
After following all the instructions I ended up with what I thought was a tight belt with little flex, I ended up with fairly even gap on the motor mount adjustment plates.
That's good. Normal, based on my sample of one.
Started up the motor. Ran very smooth and quiet at 500, 900, 1200 rpms. At 2,000 slight rattle (bearing?) and more noticeable at 3,450. Loosening the eccentric bolt, the rattle became less, but still noticeable. It was impossible to rotate the eccentric with screwdriver as instructed in video and manual. This was so with the bolt totally loose. I remember several days ago when there was no main belt tension, it was easy to rotate that eccentric with the screwdriver. What next?
If it won't move at all, the belts may be too tight. See below. But it is normal that it is much harder to turn with both belts on. Either way you turn it, you are tightening one of the already tight belts. So it may take much more torque from the screwdriver than you expect.
I also noticed when I shut the machine off, the main belt and motor pulley were quite warm. Is that normal? Could I have the belt too tight? Yes, it is normal. But yes, also possibly too tight and too warm. There is a pretty detailed thread on this where the OP measured temps with an IR thermometer. You've probably noticed the lack of explicit direction in the manual and video.
As I await further guidance, Thank you.
hal
All things considered I would try backing off the motor belt tension 1/4 turn on both setscrews, redo the motor pulley alignment, and try again on the balancing. The belts get pretty warm pretty fast, especially at higher speeds, but unless you have a way to measure that part is pretty subjective. In my experience if you loosen the motor belt like this it will tighten back up some from the balancing.
"the side of the straight edge riding flat on the motor pulley should align to that ridge between the two belts in your picture. In other words, aligning the left edge (top edge in drill press position) of the motor pulley to the left edge of the motor belt portion of the idler pulley"
From my picture, looks like I may be way off. I'll have to go check that better.
"redo the motor pulley align" I don't understand what process does the alignment.
thanks
(you can see I like the way you did the quote responses - nice)
Referring back to your pic of the straightedge, I think you are off by about 1/3 of the width of the straightedge. Just want to make sure we are on the same page.
What I meant by motor pulley align is the same function that uses the straightedge. It is aligned by the two button head screws at the fan end of the motor. It is steps 3 and 4 in Motor Belt Tensioning. So you'll do the five steps of that procedure, but at step 2 you'll adjust the Tensioning Setscrews each 1/4 turn CCW to loosen the belt a bit. That may seem too loose, but it should tighten back up some when you "balance."
Remember that these two sets of adjustments (tension and pulley alignment) on the motor interact somewhat. When you do step 4, it may change the tension you set in step 2. I would always double-check.
I agree with the above. You should be able to slip a straight edge between the edges of the two belts to see how well they align, along with laying on pulley as described above. You should check the tension if you can't move the eccentric anymore. If the belts are out of alignment that would explain the heat, if it really is too hot, no idea how hot it should get, what you're getting could be fine.
ah ha - thank makes sense to me now. I didn't understand earlier that the bottom screw (away from motor pulley) was belt alignment and the other tensioning adjustment. Now I got it. Can't imagine coming to this understanding without your explanations. Will keep at it.
Also after I get that work done, I'll measure heat with the infrared thermometer I've got.
Looks like tomorrow I'll have time to try these. Thanks to both of you.
Here is a link to that other thread, it's to a post in the middle where the subject of belt temp Vs belt tighness comes up: https://www.shopsmith.com/ss_forum/view ... 27#p251427 Interestingly, I'm not seeing the RPM that generated the numbers. That's perhaps not as useful as I'd hoped. I loosened my own belts a bit after reading this, but there is not enough tension so I need to split the difference and try again.
Note - The writer, in a later post, cites a manual quoting 1/4" deflection of an upper poly-v belt under light pressure. That is an old manual. Later manuals used 1/8" under moderate pressure. IIRC Nick said 1/8" under strong pressure in one of the sawdust sessions. Several choices there, they were all for a "conventional" headstock. To me there is no difference in the upper portion for PowerPro, with the exception of potentially more torque. I don't know the right number, but I'm ruling out 1/4" under light pressure in my shop.
hfmann wrote:
Also after I get that work done, I'll measure heat with the infrared thermometer I've got.
That's a real good idea. All of us should start doing that and checking different parts of the machines so we have some comparative data for the future.
Hi, - Back at it again this morning. You guys sure are patient. Thanks.
"Referring back to your pic of the straightedge, I think you are off by about 1/3 of the width of the straightedge. Just want to make sure we are on the same page. "
Well.. reexamined things this morning and see perhaps I DON'T understand where the straightedge on main belt is supposed to line up on the idler. Maybe we're not on same page. Glad you checked. Here's another shot this morning of the straightedge.
motor pulley straightedge at idler lip
motor pulley straightedge aligned to idler lip.jpg (670.11 KiB) Viewed 1726 times
To me the straightedge is just a tiny smidge below the lip separating the upper and lower grooved sections of the idler. Your note referencing earlier pic saying looks off 1/3 of straightedge width and edma's comment of being able to slip a straightedge between the two belt edges makes me wonder if belts are supposed to be nearly touching?[/color]
distance between upper and lower belts on idler shaft
distance between upper an lower belts on idler shaft.jpg (670.79 KiB) Viewed 1726 times
If the upper belt is supposed to be lower on the idler, I'd wonder how to square that up with the upper drive shaft. Right now the belt looks centered on the upper drive pulley.
upper belt on top drive pulley
upper belt on top drive pulley.jpg (80.75 KiB) Viewed 1726 times
I've edited your pic to show what I think is the misalignment. The lower green line represents the edge of the straightedge and the upper represents where I think it should be (center of the flat between the belts):
Misalignment
belts on idler shaft.jpg (19.3 KiB) Viewed 1694 times
I think the error is smaller in this version compared to the one I made the ~ 1/3 width comment on, or this is a better picture. Straightedge should be long enough that you can ensure it is riding flat on the motor pulley to give the most accurate projection of the line up to the idler, I'd say 8" minimum.
I don't see anything wrong on your upper belt. You can't get the belts any closer together than you have them on the idler. That flat ridge is meant to keep the belts apart. I don't recall if Jim McCann covered the proper position in the grooves in the upper pulley, but I thought he did. The upgrade manual does not specify it.
"I think it should be (center of the flat between the belts):" That solves my puzzlement. I had assumed it was supposed to align with the bottom edge. Okay, back to the readjust that. I'm now using a stiff ruler from a combination square as the straightedge. I think that's giving me a much more consistent and accurate gauge.
To work on the eccentric adjustment I did loosen the belt tension big time and was finally able to turn it. So I kept tightening the tension just to the point where I could no longer turn the eccentric. However, I was surprised how much flex there was in the belt at this point. I don't know how to measure that flex amount. Everything sounds quiet and smooth up to 2000 rpm where I started hearing chatter. No matter where I turned the eccentric I couldn't totally eliminate the noise. It was way noisier at some points than others. Maybe when I get the alignment where it should be, it'll settle down.