What did you do today?

[CCWKen]

Around corners, the outside needs to turn faster than the inside of the roller(s)--like an auto differential going around corners. Not sure how you'd make that happen with a seam welder. When doing auto upholstery, it helps to raise the panel at an almost right angle so the foot/needle is seeing a flat seam in the vertical. (non-walking foot machine)

[3 Phase Lightbulb]

Around corners, the outside needs to turn faster than the inside of the roller(s)--like an auto differential going around corners. Not sure how you'd make that happen with a seam welder. When doing auto upholstery, it helps to raise the panel at an almost right angle so the foot/needle is seeing a flat seam in the vertical. (non-walking foot machine)

Or just power one wheel and let the other wheel spin freely. Or just use one powered in the center instead of two wheels.

[Black Forest]

Or just power one wheel and let the other wheel spin freely. Or just use one powered in the center instead of two wheels.

The two rollers I refer to are a top and bottom roller not side by side.

[boslab]

Melty sewing machine, leister guns are great, they do give nice burns too!, expensive animals
Mark

[MrFluffy]

I've been torn with putting the headstock back together with beat bearings on the surface grinder, but funds for a 6" piece of 2.5" bearing bronze stock, its just not going to happen right now (unemployed, household budgets etc). So I added a shim around the outside of the C shaped bearing between it and its housing, and this snugged up the fit a little too tight but way better than the spindle flopping about previously. So I decided I would try to polish off the high spots with what I had to ease the bearing a little.
I turned a bar to the same od as the spindle and cut tiny axial lines in it 0.002" deep by advancing the saddle back and forth with the spindle stationary to carry some abrasive.


Then worked through the 5 grades I have of abrasive polish finishing up with brasso. This is the closing "shoe" part of the bearing, and you can see clearly the 3 damage spots, I decided to stop here and treat them as oil pockets rather than risking it running out of adjustment because it was too thin. Really glad I did this. Contact surface is way better when tested with blue after than before the operation.


Assembled again, made sure all oil way passages were unobstructed (I'd punched the shim for this, but checked it hadn't misaligned) and filled the well with fresh hydraulic oil, bedded it a little and measured my handiwork with the tenths clock. Pleased so far with the result.
Now I have to fit the oil seals again and run it up for a hour or two, and readjust as everything beds back in to everything else. Feels like every two stroke bike I've ever built, if it doesn't seize during run in it'll be lovely I hope...

[MrFluffy]

And today, I tested my handiwork on the surface grinder head fettle after getting to and getting the head back on the machine. Better but no cigar.
The block on the left is before the rebuild, and the one on the right post, although its still settling in.


Everyone seems to say you don't need to balance wheels on this sort of size surface grinder, but I noticed without the hub mounted, the spindle ran smooth and vibration free, but once the wheel was in place, the machine had picked up a new vibration so I feel it was worth checking out. Except I have no balancing rig.
I do however have some vee blocks, two extremely accurate straight lengths of tool steel (taken from a precision electron micrometer stage) some random shims and a box table. I know the "knife" angles are too obtuse but I'll address that in future. I just think its worth testing at least this one occasion. I levelled it to within a fine division on my machinists level so hopefully that's enough.


Then measured up the hub and did some trig and came up with 7.6degrees taper for the arbor, set the compound on my lathe to halfway between 7 & 8 degrees, cut, tested against the hub, adjusted with tiny nudge + relock compound, recut, repeat until blue printed across the two bands. I'll cut the cone shape tomorrow now though.


Taking a few hours each night, it might be rubbish and worn out after it anyway, but at least I'll know I've given it the best shot I could with what I have to hand.

[Cenedd]

Definitely an improvement. The left one looks slightly smeared, the right perhaps a bit grainy but definitely better. You definitely deserve a cold beer. I think you're on the same side of the pond as me but in case you need it to be five O'clock somewhere, it's definitely gone that here!

[RichR]

I'd call that a substantial improvement. The block on the left showed a scalloped pattern across its surface which I don't see on the block on the right.

[MrFluffy]

Cenedd Not quite, I'm in mainland Europe so a hour ahead but I'm originally English which is where all the little language colloquialisms come from.
Looking at that wheel arbor, its also just occurred to me that its only got 2 balancing weights. My mind is trying to work out how you'd balance out a heavy spot with only two weights and failing. I wonder if someone has just lost a weight and left it like that in the past.
Also spent a age digging through the ws sopoko site for if it uses the same hubs as a more common grinder, and no, nothing close, the large end of the taper measures at 1.46", the closest is 1.50" on some large grinders.

Thanks RIch, but I hope there's better to come if I persist.

[Cenedd]

If you have two weights and they are deliberately weighted off-centre then rotating them would allow you to either balance them (for an already perfectly balanced wheel) by making them 180° apart or compensate for an off-balance wheel by having them set other than 180° apart. Difficult to know if this is the case from just one blurry pic of the wheel but I might have hit the nail on the head for a change

[RichR]

... Thanks RIch, but I hope there's better to come if I persist.

With the scallop marks gone, it's possible you may be looking at other issues, such as a wheel that needs dressing to expose a fresh cutting
surface, a different grit or hardness altogether, or possibly grinding wet instead of dry.

[MrFluffy]

Because otherwise I wouldn't sleep thinking about the what if of it, I went back out and warmed the spindle up again after removing the balance weights completely then dressed it in fresh. I agree now it might be the steel composition (its just junk out the scrap bin) or other issues, but it feels smoother again. I'll finish the arbor spindle off tomorrow and see how badly it needs balancing and if I can get it close with just the two weights re-added.

[Mark Rand]

Method for balancing wheel:-
1). Dress the wheel.
2). Arrange the weights so that they are directly opposite each other. Orientation doesn't matter.
3). Place wheel on balancing stand and let it come to rest.
4). Arrange weights so they are at 3 'o' clock and 9 'o' clock positions relative to the resting position of the wheel.
5). Move the weights upwards by equal amounts until the wheel will come to rest in a random position.
Done!

I found I needed a balancing stand when I came to recommission my dust extractor. The fan was out of balance by about 100g.cm or 1.5oz.in. I ended up making a wheel type stand after messing around with straight edges and levels. In the process I balanced all my surface grinder wheels as well. Definitely makes a difference .

Oh:- Jones & shipman hubs are a 15° included angle on the taper. Don't know if that's compatible with what you've actually got. The Sopko site has got the dimensions on their J&S page.

[10KPete]

Mark, what did you use for bearings in your balancing stand? I'm about ready to cut metal to make one and was going to use small, shielded not sealed, ball bearings.

Thanks,
Pete

[MrFluffy]

Method for balancing wheel:-
1). Dress the wheel.
2). Arrange the weights so that they are directly opposite each other. Orientation doesn't matter.
3). Place wheel on balancing stand and let it come to rest.
4). Arrange weights so they are at 3 'o' clock and 9 'o' clock positions relative to the resting position of the wheel.
5). Move the weights upwards by equal amounts until the wheel will come to rest in a random position.
Done!

I found I needed a balancing stand when I came to recommission my dust extractor. The fan was out of balance by about 100g.cm or 1.5oz.in. I ended up making a wheel type stand after messing around with straight edges and levels. In the process I balanced all my surface grinder wheels as well. Definitely makes a difference .

Oh:- Jones & shipman hubs are a 15° included angle on the taper. Don't know if that's compatible with what you've actually got. The Sopko site has got the dimensions on their J&S page.

Thanks, that clears up if you can balance with two weights, I finished the arbor yesterday and tested it on what I had so far, and the hub had a heavy spot without the weights and without a stone mounted. I mounted up a new stone but couldnt get it to balance so will follow your process today and see if I can get it right.
On the wheel type balancer, thats sort of what I'm leaning to when I fabricate a proper one, but I might make it a bit bigger overall so I can balance motorcycle wheels on the same rig too. I've been meaning to make one of them for a few years too :-)

Pete, the tip is apparently to take off the seals and lubricate the bearing with the lightest oil you have to reduce stiction. I read one person used ceramic bearings because they have less rolling resistance too. Making the disc wheels large diameter reduces the effect of the bearing friction on the overall accuracy of the balancer, so the bigger diameter discs the better.