reible wrote:OK now I can see what you are talking about... this is termed hysteresis or lag. I went out to the shop and put on one of my 12" disk sander on then clamped the end of the idler shaft as it comes out the other side of the housing. I adjusted the table height flush with the outside edge of the sanding disk. I made a fine line on the edge of the disk then turned the disk clockwise and made a mark on the table that aligned with the disk mark. I then rotated the disk counter-cloclwise and made another mark. When I measured the distance between the marks I got .155".
So a bit of math, the length from the center of the disk to the edge is 6" (to be honest I didn't measure this) I come up with about 1.4794 deg.
I got this shopsmith in 1976 and upgraded the quill since then... still no lag like you have??
Ed
Hi Ed!
The amount you measured .155" rotation on a 12" circle would translate to close to 1/8" on a 10" circle, wouldn't it? No, I'm not trying to get into a math thing here. (ha!:D ) Just trying to find out if normal lag is 1/8".
In your opinion, is the advice I gave JC correct?
Octogenarian's have an earned right to be a curmudgeon.
Chuck in Lancaster, CA
Just had to add my two cents, I had the same problem a year ago. The setscrew in the top of the headstock that retains the quill was worn. If you remove it there is a round part on the bottom that rides in the slot in the top of the quill. look at the round part and see if there is a flat spot on it that was worn into it by the quill rotating, you might have to use calipers or a micrometer to measure if it is out of round. If you need a replacement it is a special Shopsmith quill retaining setscrew. Do not try to use a regular setscrew to retain the quill.
If the setscrew is worn and you have to order a new one you can get buy for a few days by just rotating the old setscrew 1/8 turn from the current position. Also check that it is installed correctly. I think you bottom it out then back it off 1/8 - 1/4 turn.
I just could not lay back so I retook all my measurements of the lag to verify it for a second time.
Taking advice from all of you I extracted the quill with bearings and spline shaft.
Took a caliper and measured each spline all along. Found no apparent or unreasonable wear (if any). Compared every spline and found that the average variation was only 0.04" which is well within acceptable tolerances for equipment like this.
I then blew all the components to clear out any saw dust. Waxed and dry lubricated the parts and reassembled the pieces since I could not find anything of notice.
After assembling all the components I made a second measurement of the lag, and don't ask me how or why (or whether on reassembly I rotated parts), when I measured again I found a lag of 0.132 which is as close to 1/8" as possible.
If things baffle, this one does because I cannot vision any way I could have two readings even if I had rotated the spline and engaged different grooves.
I had my son with me when I took the measurements and he cannot explain the results either.
All I know is that till I experience something similar I will continue to run the SS. I still do not know what I learned.
Thank you all for your patience.
Embarrassed to say it, JC, but I can't seem to find anyone around here at Shopsmith who can tell you exactly what you learned. It seems to us that the lag you are measuring has more to do with how well the splined end of the drive spindle (518207) fits the nylon coupling (514083) at the end of the drive sleeve (518145) than it does with the bearings in the quill. My guess (and it's only a guess) is that what you've learned is that this lag increases with normal wear and tear, and that you may be able to temporarily reduce it by removing the quill and replacing it so that different splines on the spindle engage different slots in the coupling.
As for the tolerances on the quill bearings, we measure that by runout or how closely they hold a center. Runout affects the precision of your woodworking far more than lag. The maximum allowable runout for a 2-bearing quill when it's new is .001". The old one-bearing quills could hold .005" on a good day with lots of coffee.
As for the tolerances on the quill bearings, we measure that by runout or how closely they hold a center. Runout affects the precision of your woodworking far more than lag. The maximum allowable runout for a 2-bearing quill when it's new is .001". The old one-bearing quills could hold .005" on a good day with lots of coffee.
Where is the proper place to measure this runout? I'm sure I've seen it, but cannot locate it now. I have a 1954 greenie. The original quill had some play in it. I replaced it with a single bearing quill that has no noticable play. The problem is there appears to be what might be a slight bend in the spindle. This is noticable with a long drill bit and sometimes I get upper cuts from the back of the saw blade even though I think everything is properly aligned.
I did buy the dial caliper from Shopsmith. If I take one of my blades and spin it by hand with the dial indicator located near the edge of the blade, I get a wobble of about .007 per 180 degree turn. I have tried this with two different arbors and two different blades just to make sure it wasn't a blade and/or arbor issue. Both blades lie perfectly flat on the table. Does that mean I need more coffee?
Why are you concerned about the lag? It is not a metal lathe that requires precision. Runout is many times more important. Somewhere in a past post, someone, maybe Nick, said to put wheel bearing grease into the Drive Sleeve inside splines. Push the quill shaft into the drive sleeve until grease comes out and you can bottom the shaft. I do it to all Shopsmiths I repair or rebuild. I do it to both the gilmer and poly-v drives. It helps eliminate some noise when the splines were dry.
Bill Mayo
Nick wrote:[As for the tolerances on the quill bearings, we measure that by runout or how closely they hold a center. Runout affects the precision of your woodworking far more than lag. The maximum allowable runout for a 2-bearing quill when it's new is .001". The old one-bearing quills could hold .005" on a good day with lots of coffee.
annbill.mayo wrote:"Why are you concerned about the lag?..."
Bill Mayo
The answer is - Because! In the past year, I had noticed a lag never noticed it before - was a little concerned if something was wearing out. Then jcbrowne posted his question, mentioning a lag (we called it "play" for a short time) of .425". Now that seems a little excessive! The lag on my 510 is 1/8". I wondered if that is within a normal range.
Seems to me that if repeated wear on the drive and ring assembly (514083), or the splines on the spindle could cause the lag to increase.
In another part of the machine, I've witnessed excessive wear inside the control sheave shaft, causing the short key to roll and wear both the key and the keyway so they were no longer squared. I pictured a somewhat similar thing happening inside the drive ring and the on the spindle splines. I realize that one key is not too comparable to a spline with it's multiple protuberances so that comparison may be far fetched, but it appears that this type of wear happened to jcbrowns unit. The Control sheave shaft is bronze and the short key is steel. The bronze shaft will wear faster than the key - especially with scant lubrication. That's what happened to me. I didn't know, and still don't know if there is lubrication on the spindle shaft.
Octogenarian's have an earned right to be a curmudgeon.
Chuck in Lancaster, CA
Well, I thought I had resolved my problem when today I found the lag increased again to what I had found initially.
This time I decided to take the power plant to pieces and check everything (meanwhile give it a full reconditioning).
In doing so I noticed play in the spindle assembly (62) within the quill (59). I extracted the spindle assembly and found that both bearings were worn out completely due to lack of lubrication (dry as the desert). Obviously not sealed units.
I extracted the head bearing and expected to find a sleeve (spacer between bearings) as on most other machines but instead discovered that the second bearing (the smaller one) in fact is mounted from the splined end with the spline inserted into the collar/spacer and retained with an expansion pin.
This pin had play and accounts for the excess of 1/8" lag I discovered.
I will change the bearings and reinsert an expansion pin and see if now this issue is resolved. I imagine it will also reduce vibrations and consequently noise.
Nick, Is there any reason the spindle assembly is made in 2 pieces instead of one with a sleeve/spacer? The way it is assembled presents too many possible points to wear out and create play. In fact this assembly does not offer the best rigidity to the output spindle (blade mount).
Other than the fact that the second bearing is smaller than the first one [both could be the same size] I would see no reason to explain why the spindle assembly is made this way.
) Just trying to find out if normal lag is 1/8".
