Thread: Restoring a Jones and Shipman 520 cylindrical grinder II

[Before the reshuffle, I was posting in this thread -
//metalworkforums.com/f65/t184859-keeping-jones. This is a continuation of it]

I've been a little slack lately on this project as I've had all sorts of other things to do but managed to get some shed time at the same time as motivation so away I went.

As well as the drive system, like a T&C grinder, the grinder is not much good without the accessories that bolt on. Previously I made up some patterns but when they were cast I found that I'd mucked up some position features so new patterns were required. At that stage I put it in the later pile...
Thanks to a block of CI from Kryn, a radius sharpener from Eskimo and some inspiration from other posts, I had another go but this time direct to CI rather than getting it cast then cleaned up. This is the simpler of the two castings, the wheel dresser. I intend having a go at the tailstock but that is way more complex and will take much more time.

The radius sharpener is important because the two features that typically identify castings from machined parts are radii rather than sharp corners and draft away from the parting line. That meant that modifying milling cutters to put a radius on the corner. Fortunately, I had a donor cutter...
P1030243 (Medium).JPG P1030244 (Medium).JPG P1030249 (Medium).JPG
The first photo (above) shows the cutter to be modified with chipped corners. Very easy to damage like this and once they are chipped need to be reground. In the background of that photo is a Darex E-90 radius cutting fixture, which I am slowly adapting to use on my surface grinder. The reason I got it was that it can grind normal cutters to have a ball nose or radius the corners, so the cutter would leave a radius rather than a sharp corner. As a cutter with rounded corners will not be as delicate, the chances are it will last a little longer too. With it I managed to radius the tips as seen in the second photo - however, lots more work is needed as the adjustments are backwards to how I need to use it. The third photo of that string shows the result when used on the block of CI.

With that cutter I could then produce the pocket as shown below. This is the block machined down to overall finished dimensions.
P1030251 (Medium).JPG

Most of the initial machining was done using a Vertex Anglock vice. Very solid but as I've removed the base to get even better rigidity from it, I could not swing it around for the angles. For that I used a copy of a 3 axis vice. It meant that I could swing the part around to put in the hold down bolt slot (as shown in the picture), but also tilt the part by 3 degrees so that I could machine the sides in imitation of casting draft. Once the machining was done I liberally radiussed the external corners to give more of that casting look.
P1030252 (Medium).JPG

This is the result, compared to a photo I have of a 'real one' (Still needs the holder for the dresser )
P1030253 (Medium).JPG dresser 4.jpg

Michael

Looks very good. How do you get on for Z axis height when you use the 3 axis vice?

It uses a little more (perhaps 100 to 150mm extra) but as my Z range is 465mm I have enough that it is not a problem for small items. The biggest problem for that vice is that it is not as rigid as I would like. This one is a copy so the name brand versions may be better (I think J&S did one) but I would still expect things to be a bit shaky. Putting the groove through for example my DOC was 1mm. Any more and things moved around too much.

Michael

Still have a few bits of CI, if you need some more for a project.
Kryn

Hi Michael
would it be possible you could do a quick sketch of the cross section of the table with rough dimensions and post it?

Phil

This what I have been basing my working drawings on.
(front of the table is to the right)

table section (Medium).jpg
These are 'as measured' and while good enough to work to are likely not 100% correct. If I had access to the original drawings I would probably find that the 14.03 should be 9/16", 40.67 should really be 1 5/8 and so on. I suspect that the basic design is just a scaled down table from larger J&S grinders.

Thanks for the offer Kryn, but this was the only small item to be made. All the other parts that need re-creation are (comparatively) much larger and I already have a bit to use for the tailstock. For the other bits I think I'll be back to pattern making when I have time. The tailstock and dresser are more important as bits the machine needs to function.

Michael

The dresser shown a few posts ago was sold as an accessory - why I don't know because dressing a grinding wheel is part and parcel of using a grinder but...
However, the tailstock is a necessity if grinding just about anything so I definitely needed one. The dresser was basically a collection of flat surfaces so relatively straight forward but the tailstock was a different matter again -
img15 (Medium).jpg
Normally I just head into these projects and do what seems best. However, some calculations are involved in getting this right and in a first for me I even sketched out a basic plan so that I had a sequence to work to. It came in very handy for working out the work holding side of things.
The first couple of steps were simple enough. I worked out that a 100mm cube of cast iron would provide the starting point but would need to be cut diagonally to get a block the right size. I spoke in another thread about bandsaws being more flexible than cold saws and this is the sort of thing I was talking about. The vice is closed on a large V block that Phil (Machtool) got for me, and the G clamp is holding the CI into the block for the cut. It took my saw around 25 minutes to cut through that lot.
P1030255 (Medium).JPG
A couple more cuts and then into the vice for the mounting surface to be put on. I had previously made up a steel copy of the bed section and my plan was to clamp the block to this so that I had a way of work holding when doing some of the weirder features. It worked well. The clamping method is just a disc nut that the bolt tightens up on. On the real machine the disc is fixed and the 'nut' is a ball handle.
P1030257 (Medium).JPG
P1030264 (Medium).JPG
So far things were simple but the degree of difficulty then ramps up. On each end of the tailstock is a semicircular boss. The one on the right end is proud of the flat surface but on the left end there is also a flange that contacts the table. To get this shape faithfully (and also on the rear) I used a ball nose cutter to take out the relief and then used the same cutter inclined to add the appropriate angles to the flanges. Once these linear features were in place I was able to secure the block to a rotary table and add the bosses, again using a ball nose cutter to get a radius around the base.
P1030258 (Medium).JPG P1030260 (Medium).JPG P1030261 (Medium).JPG
On the top is a boss for the spring centre (for easy part removal). The first one was easy as it was circular and proud of surrounding surface, but the feature that sat on was flush with that surface but intersected the sloping front of the tailstock. Note that at this stage the front was just the 'as cut' surface at 45 degrees and would be finished later on. I made up a spreadsheet to calculate the depth I needed to plunge a ball nose cutter in at 5 degree increments on the R/T. As you can see from the second photo it seems to have worked as I had a circular shape with a radius at the base that looked like it would blend in with the final surface.
P1030262 (Medium).JPG P1030265 (Medium).JPG
Three features to go -
Firstly I got out the sine table and cut the 'as cut' surface away where necessary. I was really pleased to see that the plunge cuts basically met up with the new surface.
P1030266 (Medium).JPG
Next I needed to cut the material away for the grease nipple mount. I tried calculating this out but in the end made up a cardboard model of what I wanted to do. I mounted the sine table on the rotary table, inclined the mill head and cut away. The model was correct it seems. I was asked previously about the three axis vice and using up Z. I can say that with this stack I was mm away from running out of Z.
P1030268 (Medium).JPG
Last feature to be put on was the hold down boss. This had to be at 45 degrees to the table surface but the surrounding surface was at 31 degrees. Further more, to keep that casting type look, considerable draft was needed on the sides of the boss. I almost came unstuck here as I had no way of holding the part (I thought). The boss needed to be at the centre of rotation so the previous method was out and I had not made up a small sine table yet. I'd packed away for the day and then realised that I could perhaps hold the part in the vice and position that so the centres coincided. It worked but just. The handle of the vice cleared the column on rotation with less than 5mm to spare.
P1030269 (Medium).JPG

The finished article - off tool (1st photo) and after a little cleaning up with a linishing tool (the white bits are just reflection). The original 4kg triangular piece of CI has been reduced to just under 1kg...
P1030270 (Medium).JPG P1030271 (Medium).JPG P1030272 (Medium).JPG

Looking through my photo collection I was surprised (for a low volume machine with production spread over 20 or so years) that the patterns for these parts seemed to change so much. Some are very rounded while others are more squared off. Interesting.

Michael

Unbelievable, Michael!
No way would I have the patience to replicate a complex casting like that....
I love watching your projects unfold. Thanks for taking the time to photograph and describe the steps, as you do!

Amazing Michael, nice work indeed, I have a new favourite work setup picture.



Love it. Now, if only it was a compound sine table.....

Ray

Originally Posted by jhovel

No way would I have the patience to replicate a complex casting like that...

I figured it was either make another pattern or machine direct. To wood carve the pattern probably would have taken me just as long (about 3 half days to get this far)
CNC would have been quicker but where's the fun it that? (Given the emphasis on CNC in training and that the sine table is ex-TAFE (sold off as surplus), would anyone except an old school machinist even contemplate making a part like this on a manual machine?)

Originally Posted by RayG

I have a new favourite work setup picture.

Sorry - next time I'll tidy up the tools so they are not scattered across the table

Originally Posted by RayG

Now, if only it was a compound sine table...

Yes, but if it was a compound sine table I would not have to tilt the head...
(Although I might have to put in a small angle plate?) The sine table is really nice and fits the mill perfectly but the two hold down bolts only just fit the top of the R/T

Michael

Looks good. It makes me glad we have CNC's at work, all that setup looks like hard work.

That looks amazing Michael. All that setup and the machining was probably all of a few minutes!

Originally Posted by Michael G

would anyone except an old school machinist even contemplate making a part like this on a manual machine?)

Michael

From what I have seen of some young machinists, I doubt they would know where to start with such a part!

Simon

Originally Posted by simonl

...I doubt they would know where to start with such a part

To be fair it took me a while to work it out too. The last two set ups did take longer to do than machine but all the work bringing the block to size were the reverse - the set up was straight forward; the machining took a while just to remove the volume of material.

(My thoughts in post 10 were more along the lines of whether trainee machinists are exposed to things like rotary tables and sine plates. Would they realise that it could be done without CNC? One of the reasons I don't want CNC in my shed is that working out the method is part of the learning process)

Michael

Originally Posted by Michael G

One of the reasons I don't want CNC in my shed is that working out the method is part of the learning process)

Michael

I think you would need an expensive CNC to make something like that and be exceptionally skilled in writing the program unless you have a very expensive CAM program.

You did an exceptional job in the making of the tailstock. Next up you will need some steadies made up.