Thread: Keeping up with the Jones

I posted the initial news of the J&S in the tool acquisition thread but the continuing adventures should have their own -
I've been looking at it off and on for the last week trying to work out where to start. I have appeals on PM, modelengineer.co.uk and some others to try and get some information. Today the brochure (reproduction) arrived from Tony (lathes.co.uk) and in there was some interesting stuff about the drive system. I did not expect to find one, but it actually has a rear view of the countershaft arrangement. While not necessarily wanting to duplicating it, it is interesting to see the complexity involved.
rear view (Medium).jpg
Maximum rpm suggested for a 5" wheel on this machine is only 3900rpm but as the wheel is consumed there are 2 other speeds so that it can be run efficiently. When you are down to a 3" diameter wheel they suggest hooting along at 6750rpm. Still debating whether to run two VFD's (one for the grinder, one for the workhead) or have a similar set up with several counter shafts. The extra motor + VFD + switch gear etc will probably come close to $500 but would be a lot simpler. (Come to think of it, belts pulleys and bearings would come to...)
Another similar machine (brand is Crystal Lake) had a overhead shaft and in this photo you can just see the long roller for driving the traversing head.
grind.8056.2 (Medium).jpg

Michael

Michael, what size is the drive head motor? Could you substitue a single phase motor for it? Or do you need variable speed for it?

According to the specs, the motor is 1HP 1440rpm. I have always been taught that 3 phase motors are smoother and so for something like this better. The 3 phase makes it easier to adjust speed too rather than lots of belts. (Grinding head is listed as 3900, 5000 and 6750rpm; work head is 375, 686 and 1250rpm - within the range of VFD's)

One thing I haven't worked out is if I have two motors instead of one what the power rating of the individual motors should be. Torque of the wheel motor + cutting torque should equal torque of the work head but one is going considerably faster than the other. As power is torque x speed, ???

Michael

That work head is massive then! Most I've seem (including my Van Norman) are 1/4Hp....

You would be right about the torque - don't know about the power. If the wheelhead torque was less than the grinding wheel torque, the work would stop or be driven. But the power needs to be very little as you say ist torque x rotational speed. I guess the power of the wheel needs to be greater than the workhead or it would slow down/stop?

If you want to try my Heng Tai VFD, feel free. It's currently spare and is only about $65 to replace. Range is 0-70Hz, 0.75kW. Full English manual availalble now

Thanks for the offer Joe but I bought a spare Delta of the right size the other day in anticipation of a 3 phase drill press. That did not happen but the VFD will come in handy.

Michael

Originally Posted by Michael G

As power is torque x speed, ???

Michael

Hi Michael,

Work can be expressed as Force x distance;

Power is the rate of work (with respect to time) and so Power = work/time = (Force x distance)/time
Now, distance/time = velocity (actually it's the scaler equivalent which is speed)

So, Power = Force x velocity;

where force is measured in Newtons and velocity is m/s

Power = N x m/s
= Nm/s; where torque is Nm
= torque/sec

So, power is more equal to the rate at which torque is applied.

Can't help you with anything else though!

Simon

Originally Posted by jhovel

if the wheelhead torque was less than the grinding wheel torque, the work would stop or be driven.

Yes but in practice wont your "DOC" be just limited to which ever has the lowest torque?
The torques have to at least match, but power is fixed.
So, as wheel diameter and work diameter come into it.
So what you are really interested in is how many ftlb at a given diameter?

But as the work is normally spinning at say 10% of the wheel rpm and is normally smaller in diameter than the wheel. Unless its a tiny motor it will be the wheel hp limiting things............ I think.

Stuart

Well I've started. Despite everyone else here on the forum inspiring me not to start a new project before I've finished the last one, some of the things started to annoy me.
Tonight I replaced the handles after removing them to repaint as I found the red particularly garish. I also replaced the modern dome nut on the in feed with a flat nut as all the illustrations show them having. (Chrome on a '30's vintage machine? Pfft!)

P1020318 (Medium).JPG P1020317 (Medium).JPG
I'm particularly pleased with the traverse handle because it is a replacement. The one that was fitted to the unit was from a cheap import lathe I think as it had graduations around the edge. It took some work to find a 4" diameter handle wheel in CI, and then when it got here to make it match the in feed wheel I had to thin and profile the rim down from 3/4" thick to 1/2" thick. The polish on the edge was with 120 emery strip and it was surprising how little work it took. I think it looks much more in keeping now, and more like the original - although again there seemed to be two styles in handle as well.

Tonight's task is to speak with an 89 y.o. guy in the UK about his grinder. I'm hoping that he can help me work some more of this out including what sort of oil is used in the spindle bearings and how best to drive it. Over the last few days I've done some sketching and drive from a single motor is feasible, but requires some interesting V belt step pulleys to get there that will need to be custom made. I've put up a thread in the foundry section asking for expressions of interest if anyone casts Al but in case people miss it...

Michael

Originally Posted by Michael G

Well I've started. Despite everyone else here on the forum inspiring me not to start a new project before I've finished the last one

What a ridiculous concept! I have 3 white boards keeping track of the state of various projects and sub-projects, plus others that haven't even made it *onto* a white board. Go for it - anything you don't finish becomes a new talking point for the beneficiaries of your estate.

FWIW I used a Scotchbrite linishing belt to remove the 'patina' from all my Power SG handwheels etc. Worked great and was quick.

PDW

Looks much better than the red, thats for sure. Can i ask where you got it, looks like a nice handwheel, the one i put on the C10's tailstock was supposed to be 4" but i gave up trying to find one and used a 5" i had.

One thing i must say-WELL DONE! you managed to get something from Tony Griffiths. Despite my collection of machines the man has never replied to a single email of mine. I must have sent 5 or 6 over the last 5 or 6 years.

Ew

Reading through the literature that I have, there is a reference to the tailstock

"Tailstock spindle is prismatic in section so that the adjustment can be made to accommodate for wear without impairing the accuracy of alignment which is impossible with the orthodox cylindrical spindle"

According to Ken (the 89 yo I was talking to the other day), the spindle is almost triangular in section. Anyone got any ideas on how this works? I'm going to have to make up a tailstock and round I can do but I can't get my head around prismatic. (The tailstock takes a 0MT centre and is spring loaded (like a pump centre I suppose) to allow for heat expansion. Not sure how the wear comes in though)

Michael

The next thing to be fixed up on the J&S while I nut out the drive system are the ball handles. For some reason these were replaced by hex head bolts and nuts.

There are two designs used. On the clamps for the bed they are cylindrical with a tapered ball end handle (at 90 degrees to the fastener axis) while some of the fittings use a two ball handle that is at around 80 degrees to the axis.
img15.jpg
The cylindrical type have a slight crown on top just to complicate things. The body was relatively easily to make (I used the ball turner for the crown too). The handle part looked to be a common sort of design (well it is now), so I made up a few of those. I could have made up the ball handles as 1 piece, but there is a flat needed on the bottom of the ball (just visible in the photo below) so I made it as a two piece assembly. (In the photo above the originals look like they were made as 1 piece, but they probably had a drill jig to get the hole at the right angle). These were trickier, as the balls had to be drilled at the correct angle, the area around the hole flattened, the hole counter drilled to allow the handle run out to be within the ball and then tapped. Here are the parts after assembly but before drilling out for fitting to the grinder. I only need one ball handle at the moment but once I cast up a tailstock blank I'll need some more, so better to make them now rather than later as they may not match.
P1020354 (Medium).JPG P1020350 (Medium).JPG
These are a few of the handles that were not up to scratch (didn't look quite the same) but I'll keep them in case I need some more one day.
P1020352 (Medium).JPG

Michael

A step forward today - this grinder takes 5" by 3/8" grinding wheels, which are not a common size these days. I found one on ebay a while back and it arrived today -
$_57.JPG
The really interesting thing is that the blotter on the back has a graphic about their 50th anniversary. The Carborundum company was started in around 1890 something. That would mean that the wheel dates to around 1940. Gives new meaning to the term "New Old Stock". Should I use the wheel or frame it?

Michael

Originally Posted by Michael G

A step forward today - this grinder takes 5" by 3/8" grinding wheels, which are not a common size these days. I found one on ebay a while back and it arrived today -
$_57.JPG
The really interesting thing is that the blotter on the back has a graphic about their 50th anniversary. The Carborundum company was started in around 1890 something. That would mean that the wheel dates to around 1940. Gives new meaning to the term "New Old Stock". Should I use the wheel or frame it?

Michael

That's a good question michael, if in deed it's a serious question. If other suitable wheels are (albeit rare but) available then why not keep it for prosperity? If it's your only wheel then it would seem a shame to make a museum piece of both your machine AND the wheel purely because you don't want to use it!

Cheers,

Simon

Michael
I think Alum Oxide in grade 80 with an "N" bond would be an ideal choice for Cylindrical Grinding.
regards
Bruce