Thread: Keeping up with the Jones

Now that will be an interesting thread!

Had a spare moment today so decided to put the wheel head drive belt in. The drive belts are continuous so this involved taking the grinding spindle apart - as previously stated I wanted to check the bearings anyway, so not a bad thing.
The design is pretty simple but there were some odd parts in there who's function I can only guess at.
I'll apologise up front as I didn't take as many pictures as I should have but it should be straight forward.
Firstly, oil is key. There are two oilers, one directly over each bearing. These drip through and in turn the oil leaks through various slots and holes to oil the peripheral parts. I think the oil leaking through is also meant to flush the bearings out but as volume is measured in drips, it is probably not all that effective (although better than nothing)
P1020812 (Medium).JPG
The casting that they screw into removes, leaving effectively two cast lugs with a bearing in each.
The spindle runs on plain bearings, one end holding the wheel, the flat belt pulley between the bearings and the other end has some sort of device on it which I think is to provide preload on the shaft (more below on that).
The bearings themselves looked to be in good nick - no obvious damage, either from wear or abuse. The inside looks like this (the best photo of about 8 - damn auto focus)
P1030074 (Medium).JPG
You can see an oil distribution slot at the bottom of the bearing. Unlike a cast-in babbet bearing, these look to be something like Phos Bronze and are held in with screws - in the event of bearing wear it should be possible to replace them.
The shaft that sits between the bearings is ground and has a high finish to it. For reasons I don't understand, the bearing surface nearest the wheel is reasonably good but the one on the other end is grooved as if some grit has gotten in. The bearing itself seems fine though
P1030075 (Medium).JPG P1030075 (Medium) (2).JPG

The collar on the left end of the shaft sits against the bearing shown above, but the right end is odd. Shown below is a collar that runs against the bearing flange at the other end with a nut behind it (as assembled in the grinder) with springs on it. The nut screws onto the end of shaft and the springs bear on the collar - I can only assume to provide a force to pull the shaft to a constant position, regardless of temperature.

P1030077 (Medium).JPG
According to the pictures I have, the nut arrangement should be covered with a cover - another thing for the list.
The other odd thing which I am not sure of the function is as below.
From left to right, there is a screw with a small hole in the hollow part, a ball, a spring and a phos bronze pin that if this were a motor I would call a brush. The pin is held against the shaft by the spring pressure but the spring also pushes the ball into the seat in the screw. The ball/ spring part is acting as a one way valve but would require lower pressure in the bearing than atmospheric. As the for the pin, perhaps that is to push the shaft against the top of the bearing, removing slop to allow finishing to tenths?
P1030078 (Medium).JPG
Anyway - I can't run yet as I have to make up belt tensioners, so plenty of time to think that one through.
I'm keen to see how the shaft goes though, even with that wear. Making up a new shaft is not impossible as it is just over 7" long and the grinder can do 7"
Wheelhead (Medium).JPG

Michael

Hi Michael, The springs organised in a collar arrangement look like a bearing preload system although I really wouldn't know since I have little knowledge of that style of bearing system. I didn't think bronze bearings used a preload system but what would I know!? I'm struggling with plain old angular contact bearings! What I do know is those springs and collar arrangement are similar to the preload arrangement for the spindle bearings on my sg but it has tapered roller bearings. Cheers, Simon

The grinder is able to (or is billed as being able to) grind up to a shoulder. To do that, axial float of the wheel would not be allowed so I side with you thinking that it is some form of preload device. I would not have a clue how it should be set up though, so there may be some experimentation required.

Michael

Hi Michael,

Originally Posted by Michael G

For reasons I don't understand, the bearing surface nearest the wheel is reasonably good but the one on the other end is grooved as if some grit has gotten in. The bearing itself seems fine though

If you get grit in a plain bearing, wouldn't it effectively make the bearing "a" lap?

Stuart

I ran my finger along the bearing and it felt smooth as. Whether it was run with inadequate lubrication at one stage? The stuff that was in there was from an earlier run and has since been cleaned out when the belt was last changed? The oil managed to flush it out? I really don't know. As I said I can make a new one if necessary but I'll try it and see.

Michael

Michael, given that the proof of the pudding is in the eating....... are you going to run the grinder and see what results you get before deciding on the fate of that bearing? It may be sweet as.

Originally Posted by Michael G;1879253

The other odd thing which I am not sure of the function is as below. From left to right, there is a screw with a small hole in the hollow part, a ball, a spring and a phos bronze pin that if this were a motor I would call a brush. The pin is held against the shaft by the spring pressure but the spring also pushes the ball into the seat in the screw. The ball/ spring part is acting as a one way valve but would require lower pressure in the bearing than atmospheric. As the for the pin, perhaps that is to push the shaft against the top of the bearing, removing slop to allow finishing to tenths?

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Michael

Michael,

I thought I had seen a similar device in one of the Brown and Sharpe grinder handbooks that I have.... Their beautiful little No.10 tool and cutter grinder has a pair of spring loaded phosphor bronze shoes which bear on the spindle. In their words "springs in back of shoes insure proper contact of spindle and bearings, thus making the bearings self adjusting". End play is taken up by means of an adjustable spring loaded collar located between the spindle bearings.

Bob.

Originally Posted by Anorak Bob

I thought I had seen a similar device in one of the Brown and Sharpe grinder handbooks that I have.... Their beautiful little No.10 tool and cutter grinder has a pair of spring loaded phosphor bronze shoes which bear on the spindle. In their words "springs in back of shoes insure proper contact of spindle and bearings, thus making the bearings self adjusting". End play is taken up by means of an adjustable spring loaded collar located between the spindle bearings.

Brilliant Bob. That would explain it nicely. I am amazed by the little features like that in this grinder though - I hope that when it is going it lives up to expectations. The plate on the front says that one graduation is 2 tenths on diameter. Not even sure that I can reliably measure to that level (5 micron) in my thermally transient garage.

Michael

Bit of a 'two steps forward, one step back' period lately. I mulled over Ash's suggestion in the Cones clutches and belt drums thread (http://www.woodworkforums.com/showthread.php?t=196569) and decided that it was a good idea - but I would need to kick the left side of the overhead frame out to give myself some space. I also had to remount the back bearings because I'd calculated the belt lengths and (as you do) gone to the next size up. Trouble was with the small centre distances and pulley sizes, the tensioners would be pushing the belts into each other.
P1030104 (Medium).JPG P1030103 (Medium).JPG
I have to get the line up right but here is everything with the rear shaft back 14mm, the extensions in the frame on the left and the belt tensioners in place. The next job will be to make up the extensions for the tensioners (I already have made up the rollers) and tweak the shafts/ pulleys so things line up. I could not resist and did turn it over without the tensioner - enough to see that it will work and the wheel head shaft rotates. I do need to get some bracing on there across the vertical members though before final paint as there is a slight shake to it. One advantage of the massive CI construction of the original.

One of the things missing from my grinder was a cover on the end of the spindle for the end float device. Just a simple turning job - a cup 2" deep and 2" bore.
P1030110 (Medium).JPG
The satisfying thing was the fit - you could feel the air cushion pushing back when installing it.

Getting close...

Michael

Coming along nicely Michael. The feeling you get when you make something that fits or works so so well, never gets old in this hobby!

I thought of you today Michael, when I recommenced work on my sheet folder.

Simon

Originally Posted by simonl

when I recommenced work on my sheet folder. Simon

SAY WHAT, you mean it's not finished, yet
Kryn

Originally Posted by KBs PensNmore

SAY WHAT, you mean it's not finished, yet
Kryn

No, not yet. It's a big project and other things always get in the way but I'm back on the wagon! I have till Sep 20th to re-bump the thread which I will do shortly.

Michael, I wouldn't mind seeing a video of the grinder working, or at least running. Just a little too early for that…. even for you?

Simon

I reckon if I get a good run at it I may have power on the wheel in a couple of weeks' time. Power to the work head will be a few months more as there is a tailstock to make as well as getting coolant plumbed in and of course sorting out the drum/ clutch arrangement. Could well be complete before the folder is...

A video is trickier though. Last time I sent a disc to Ewan and got him to load it - I don't have a photo bucket account (and have no desire to have one either). From memory none of the formats here for video are things I can produce even if I could upload. The 9 seconds of gear hobbing was 20M or so? Seems a lot of data for 9 seconds.

Michael

Originally Posted by Michael G

I reckon if I get a good run at it I may have power on the wheel in a couple of weeks' time. Power to the work head will be a few months more as there is a tailstock to make as well as getting coolant plumbed in and of course sorting out the drum/ clutch arrangement. Could well be complete before the folder is...

A video is trickier though. Last time I sent a disc to Ewan and got him to load it - I don't have a photo bucket account (and have no desire to have one either). From memory none of the formats here for video are things I can produce even if I could upload. The 9 seconds of gear hobbing was 20M or so? Seems a lot of data for 9 seconds.

Michael

Looking forward to more pics then if no video. Yes, you may well finish before my folder. But then you're fixing a machine, I'm building one!

Simon