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View Full Version : Cylindrical Grinder Rebuild - WIP



jhovel
24th Jan 2016, 09:17 PM
Well, I feel its time I post a bit about one of my latest projects.
I actually been working on it for several weeks, but with little to show....
A few years ago, I bought the smallest two machine tools from the demolition sale of a 100 year old engineering workshop and foundry here in Bendigo.
One was a 60's Servian pedestal drill press, since restored and in daily use. The other a 1920's Van Norman cylindrical 'piston' grinder.
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RayG and Josh helped me collect and unload them - which was greatly appreciated. We ended up having to dismantle the grinder to be able to move it. VERY heavy castings.
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This is the only documentation I can find on the net: and ad from 1922
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The machine was missing the spindle drive motor, the grinder head lead screw and nut (and its mounting post), tailstock, traverse hand wheel and the entire cooling system - and lots of hardware.
The spindle bearings were shot and lots of parts seized, and all of it rusty, grubby and lots of it knocked about.
However, closer inspection of the slideways showed little and even wear, relatively easily restored to functional.

So, progress to date is best illustrated in photos. Some of the parts I hade to make from imagination. GregQ gave me a leadscrew and nut some time ago from his left-over stocks. That truned out to be perfectly suitable at 3/4"x10tpi, giving a handwheel scale resolution of 0.0004" per division! The mounting post for the nut was the most tricky part to make, but came out functions well while looking ugly :) .
All bearings had been greased instead of oil lubricated as designed, so that took a bit of extra cleaning....
This isn't intended to be anything like a faithful restoration, rather a rebuild to make it usable.

The workhead spindle has a continuous taper bearing for its full housing, with a step turned halfway for mounting and adjusting a plain bronze thrust bearing.
I chose to use a 900rpm 3 phase 1/4HP motor with a single reduction belt drive to replace the large dual reduction someone had fitted along the way in lieu of the original gear drive. A small Siemens VFD will allow me to vary the work head speed.
I contains an odd sized collet and draw bar that has had a drive flange brazed to it along the way. I may use that to fit a small 4-jaw chuck in the future. That collet is also bored to fit a #3 Morse taper centre - but only for the first third of its length....
I was give a tailstock of unknown origin some decades ago. It has now found a new home after much modification to reduce the centre height to suit the workhead....
The spindle took standard imperial sized taper roller bearings that I got locally. The drive motor is a 2HP 1440rpm 3-phase whihc will be driven by a machine mounted 1.5kW VFD that I found cheap a while ago. It's an Italian Bonfiglioli Vectron Syn10 and is waterproof to IP65S.
Enough chatter. Looking forward to fitting electrics and making it work....
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jhovel
24th Jan 2016, 09:32 PM
A few more photos to bring progress up to date:
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jatt
25th Jan 2016, 09:48 PM
Good to see it come back to life. Last time I saw it, it was looking quite unloved in the "to do pile"

jhovel
28th Jan 2016, 07:52 PM
A bit more progress was made: the grinder lives indeed! Very nice to use too.
But what a mess it makes!!!!! I can't believe the amount of dust it throws about!
I haven't started on the coolant system yet, but it is clearly required - apart from removing the heat generated by cylindrical grinding.
The other thing that surprised me is the power cylindrical grinding requires. This machine now runs a 2HP motor and it is not difficult to stop by grinding depth of about 0.1mm or so.
I also have to learn a lot about grinding wheels yet. The wheel that came on the machine is very soft (bond) although it is a carborundum wheel. I thought I'll persist with it for the moment until I learn a bit more. I have 3 different grades of Aluminium Oxide wheels to suit it, but don't want to damage them just yet by operator ignorance or error :)

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PDW
29th Jan 2016, 09:32 AM
Hmm, interesting. I have a 1HP motor on my WIP but haven't done more than see that it turns the spindle (and the spindle bearings don't overheat as they're plain bearings last used over 30 years ago).

You saw my grinder so you know what I'm dealing with.

Does your have powered table feed and automatic increment of the cut?

I see your work head swivels but it looks like the table is fixed.

Nice restoration job, now the Kearns O type is about sorted my cylindrical is next in the queue. Got to get some 25mm wide by 3mm thick flat belting & alligator clips to progress further.

PDW

jhovel
29th Jan 2016, 12:13 PM
Hi Peter. I look forward to your CG progress report.
No, this one is all manual and there is no swivel table. Tapers can only be ground held in the workhead.
It was designed for local motor workshops. The envelope is quite small: about 5"dia x 14" between centres. Internal grinding is possible as the spindle can be wound to the workhead centreline (without the guard of course). But only with relatively large wheels or points. I'm not sure yet how I can adapt it for smaller internal grinding. There is a mounting face on the front of the spindle that might be usable to attach an air or electric high speed spindle...