Thread: Cash Mill rebuild

Oh well, couldn't stop thinking about it after tea... so went back to it for a bit....
I figured I would start getting used to handling the granite lump.... Not so easy at first
IMAG1293.jpg
A bit too much ink on it to start with, but after wiping it a little and getting used to placing instead of 'plonking' it while hanging on the jib, I started getting the hang of it.
IMAG1294.jpgIMAG1295.jpgIMAG1296.jpg
as the blue was getting thin and the heavy granite plate a bit tricky to handle consistently, I thought I'd have a shot with some contrast and the small = light granite surface plate.
IMAG1297.jpgIMAG1298.jpg
This time I attacked it with the hand scrapers. Oops, I need to get my hand and eye in again... that looks like chicken scratchings again. Actually not that bad, but the photo flash seems to have reflected better on the narrow marks....
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OK that's me for tonight.
The third last photo shows the front bearing and the spindle lightly sitting in place (sealed in with a plastic bag). Just wanted to get a mental picture of how I might arrange a 'tramming arm' (not to tram the spindle of course, but the 'tram' the slide ways).

Looking good Joe,

Seems like the Z way were not too bad on the cash. What setup are you planning on using to test for perpendicular to the horizontal spindle?

Cheers,

Simon

Yes Joe do tell!

I'm thinking a level and jacks, so am interested to see what you have in mind.

Great work so far.

Stuart

OK, here is my current thinking:
Anything I fix to the spindle sticking out while the column is lying on it's back will deflect = no use.
So measuring/confirming the angle with the column standing might be possible. If I could level the machine so the spindle is exactly level, then I could use gravity to confirm a right angle - except that any force, even the force of a test indicator would deflet whateve I hang off the spindle a little... and I would probably not be able to eleminate any angular error either.
So my current solution idea is to leave the column on it's back, install the spindle and fit the horizontal milling arbour. I'd then confirm or correct so it has no runout (meaning it is exactly in line with the spindle). I might even fit the orverarm support to hold it still. I could then hold/clamp on my new 12" 'master square' and then run a height gauge between the square and the slide surface I've been scraping. I figure I could rotate the spindle a few degrees this way and that to check along several lines across the width of the slides.

Please anyone chip in with other/better ideas.

After that, I'll have to correct any error I find on the dovetail surfaces. So I'm hoping that I find no error or very bloody little! I guess I cross that bridge when I get to it....

There is likely to be a little delay in progress, as I jammed my finger quite badly today and I think I need to nurse it for a day or two. Back to electronics for a bit....

I was thinking.. we can assume the the face around the spindle is flat and square to the spindle(ok fine you can check it and if it isnt make it so).
Level that face.
Check the ways are also level.
Job done....... or just started, depending on what you find.

I would think the error would depend just where the wear was. If the wear was mostly in the middle with little at each end then you'll likely be pretty close. If you have a fair bit of wear at the top, a bit more than that in the middle and none at the bottom.....you might have a way to go. We'll see.

Sorry to hear about the finger.... hope it looks and feels better in the morning.

Stuart

There is likely to be a little delay in progress, as I jammed my finger quite badly today and I think I need to nurse it for a day or two. Back to electronics for a bit....

Stuart,
that's an idea I'll check into tomorrow.
The 'face' around the front spindle bearing is actually a counterbore. So making that flat if it isn't might not be so easy.
bearing_mount.jpg
The rest of the face of the machine is 'war finish' i.e. painted as cast and without filler. I intend to level and scrape a couple of rectangels for fitting magnetic gauge bases above and below the spindle sometime in the future - maybe while the thing is lying on its back might be easier.
However that won't help with this.
If that ring is flat and at right angle to the spindle, I could sit a large ring cut to suit in it and then sit my straightedge or prism onto that and check the heights. That looks like a good option!
Thanks Stuart!

I've attached a couple of diagrams from Connelly to illustrate how he does it, but basically he uses a dummy spindle with a truss type indicator holder. If your indicator holder has a decent depth of section then deflection should not be an issue. Some 6 or 8mm rod in a triangular arrangement should do it. You can always check your deflection too - perhaps make up the holder and put an indicator on, jot down the reading and then add a weigh equivalent to the indicator (such as another indicator) and see how much deflection you get.
MTR (Large).jpg

Michael

Thamks Michael. I've got Cconelly's book and will do a bit more reading there. Had been looking at my other references already....

I was going to look at MTR but it occurred that Connoly's tests are shown on a machine like mine where you have the spindle in the middle of the ways with a decent amount of way above the spindle to test as well as below.
Good luck!

Ew

A Cash mill in use at Fishermens Bend during WW2

https://collections.slsa.sa.gov.au/r...3/73/6/VOL2/35