Piston Grinder

**Oldneweng** · 15th December 2013, 04:31 PM

As mentioned briefly in the "Good Buys" thread last night, Yesterday I picked up a piston grinder from Harty69. He bought it along with the shaper I bought off him (I think) at the request of another Forum member who hasn't been heard from since. I paid what he paid, $100.
Here it is on the ute.

100_0438.jpg

It has been sitting unused for a long time. It has some rust issues. The tailstock will not move. I did not force it. Internal 240v wiring is perished. This is only 2 sockets and 2 switches tho. The grinding wheel spindle motor is 3ph 1hp 2880 rpm which I may change to single phase. I do have a 2hp one which is surplus to needs at the moment. It ran the old shearing plant. The work spindle drive motor at left in picture above works but it is a replacement. Only 2 bolts line up with the mount holes so that is all that was used as can be seen below.

100_0448.jpg

The pulley on this motor does not run true. I have an idea that it would be better if it was running true. I cannot tell how the pulley is mounted to the shaft at the moment. There is a lot of dust and dirt caked on there. It does appear to have just been jammed on tho.

100_0450.jpg

The grinding wheel spindle turn ok and does not have any detectable movement. It sounds like bearing race's inside. Probably need replacing tho as you can hear them. The belts as seen in this picture are stuffed and at least one is the wrong width. I don't have a key to suit this chuck so I have not tried it but it obviously needs some TLC.

100_0453.jpg

The Tailstock.

This grinder is not going to get any work done on it until I have cleared away some of my existing projects. I don't know how much work it needs nor whether I have the ability or knowledge to get it back into running order again. I will see how it goes.

Dean

**jhovel** · 15th December 2013, 10:34 PM

Congratulations!
That looks quite deteriorated... sad.
The table looks a lot like my 1925 Van Norman piston grinder.
The flat face on the front of the spindle is just like mine - it was used for a swing-down turning tool. With the addition of the piston grinding attachment to the bed, the part that makes the piston rock back and forth twice per revolution to get the oval skirt cross-section required, this allowed pistons to be turned oval first before grinfing to size.
Without the cam operated piston grinding attachment, you have a cylindrical grinder that will be very capable once restored!

**Oldneweng** · 15th December 2013, 10:53 PM

Originally Posted by jhovel

Congratulations!
That looks quite deteriorated... sad.
The table looks a lot like my 1925 Van Norman piston grinder.
The flat face on the front of the spindle is just like mine - it was used for a swing-down turning tool. With the addition of the piston grinding attachment to the bed, the part that makes the piston rock back and forth twice per revolution to get the oval skirt cross-section required, this allowed pistons to be turned oval first before grinfing to size.
Without the cam operated piston grinding attachment, you have a cylindrical grinder that will be very capable once restored!

Swing down turning tool? Thanks for that. So thats how you true the support cones etc. I have seen countless pistons ground but cannot for the life of me remember exactly how the cam operated except that these grinders were far larger and I believe the cam operation was a fixture built in to the machine. I guess if I have to grind pistons I can grind the skirt relief on the bench grinder.

I am hoping to have a cylindrical grinder eventually. Maybe even some T&C capabilities.

Dean

**harty69** · 15th December 2013, 11:18 PM

Hi Dean

glad to see it made it home safe look forward to seeing run again

cheers
Harty

**jhovel** · 16th December 2013, 12:35 AM

I have the cam fixture for mine. It is still rusted solid. I put thome penetrant oil on it every time I think of it. When I get it to move, I'll clean it up and take some photos. Mine mounts to the bed in front of the drive unit and has a movable drive joint to accommodate the rocking motion of the piston cone and the spring loaded rear centre.

**Oldneweng** · 16th December 2013, 07:03 PM

Originally Posted by jhovel

I have the cam fixture for mine. It is still rusted solid. I put thome penetrant oil on it every time I think of it. When I get it to move, I'll clean it up and take some photos. Mine mounts to the bed in front of the drive unit and has a movable drive joint to accommodate the rocking motion of the piston cone and the spring loaded rear centre.

I hope you have just put some penetrant on as I have reminded you

. I will be very interested to see the photos and how it works. What I remember of the ones from long ago is that the cam arrangement was at the back and not easy to see. I had to ask where it was IIRC.

Dean

**Gammaboy** · 17th December 2013, 09:01 AM

Have heard stories of things (Well, recovered WW1/WW2 guns) being rusted solid, and being sat in a tub of Molasses (diluted 5:1) for a month or so, and coming out able ot be easily dissassembled - might be worth a try for the Rusted solid cam fixture?
The Molasses acts as a chelating agent.

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