Churchill Crankshaft Grinding Machine Restoration

[Kenny G]

Having always had an interest in how to make and grind crankshafts I took the plunge (literally) and found an old Churchill CRM Offset Crankshaft Grinding Machine and thought I would share the experience!
Myself & two colleagues drove to Yorkshire last April to extricate 7.5 tons of machine that was destined for the scrap yard. After a hard 3 hours we got it out and loaded onto the truck and headed home to South West Glasgow.
Once in position I wired it up and all was found to be working with exception of the hydraulic traverse to the table. A wiring fault was found and rectified which got the table working!
This is the fist time the machine had worked under power since 1984? Now that I was happy it was working, I set about stripping off some of the parts for cleaning, inspection and preparation for painting.
Progress was going well until the end of August when disaster struck. I snapped my achilles tendon in my left leg! As I am not exactly in the fisrt flush of youth recovery was slow, very slow!
Everything came to a halt and I have only this month been able to start work on it again. I am hoping to have it ready soon enough to set up an old crank to see how accurate it will grind. I also managed to pick up an American Arnold gauge or in process gauge that measures to 1 tenth of one thousandth of an inch! Not that I expect this age of machine to grind to that tolerance? If it can achieve .0005" that will cover the cranks I intend to grind?
Anyway I've prattled on enough the pics below show it as it was in its last home, the next as it is emerging into daylight after some 35 years. The last 2show it back here in Scotland.
If there is enough interest I'll post progress of the restoration. The goal is to grind a Rolls Royce Merlin V12 Crank that I believe this grinder was capable off back in the day? And before anyone pipes up, I know that's a tall order both in terms of being able to achieve and indeed find one!
Might have to settle for a Jag V12?

Kenny G

[Mark McGrath]

Welcome Kenny.I think you and I may have spoken in the past re Lumsden grinder.
Anyway good luck with the Churchill.I know a guy who may give you Jag cranks once you prove you can do them.
Mark.

[Kenny G]

Hi Mark. I do remember talking to you, just a pity the Lumsden grinder was so big. Thanks for the welcome and encouragment. I'll let you know how things go!
Kenny G

[wierdscience]

That's quite an undertaking!

[John Stevenson]

Same machine that I learnt on.
Elf and Pastry would have a fit nowadays letting 17 year old lads loose on one of these with a Merlin crank in the chuck.

30" x 2" wheel, not for the faint hearted.

Kenny, you need an umbrella for that machine, not because it's raining but to change the wheels.
Flat strip with two holes in it welded to a round umbrella handle upside down. the strip bolts to the wheel carrier, should be two tapped holes in it already and the crane goes on the loop of the handle, wheel and hub is in perfect balance and rocks onto the shaft.

Spindle is on hydrostatic oil bearings, allow it to run and warm up for 1/2 hour before starting work or you will get flats all over the journal.

Before anyone says anything about the two skates, one at either end on a top heavy machine like this, the back of the machines sticks out TEE shaped and I dare say there is another one or two skates under than making it very stable.

[J Weber]

Wow,Pics of the rebuilding would be nice.A video of it in operation would be real nice also.

[John Stevenson]

Two types of crank grinder, the one like Kenny has where it throws the crank.

http://www.youtube.com/watch?v=yE-du...eature=related

And you have 4 setups per crank to do, mains on centre and then throw the crank out of line to do 1 and 6 journals, then 2 and 5 then 3 and 4.
That's what the big balance weights are for on the ends, you use the power meter to check balance, if it out of balance the meter is up and down to compensate.

Newer type grinders are where the wheel follows the crank

http://www.youtube.com/watch?v=MK-pNGHBadg

Only one setup, on centre, you do the mains and the wheel follows the journals.

[Kenny G]

It was easy everyone would want to have a go!

[Black_Moons]

Why would you need to do offset grinding on a crank shaft?
I could see cam shaft sure, But a crank shaft?

[Kenny G]

John.
Thanks for your comments which are much appreciated from somebody that has worked with the machine. Regards the move, we had a total of 5 skates under it, 3 under the table and 2 under the T shaped body at the back. The first part of the move was the worst as it was buried 100 yards into the building where a wall was then built to enclose it some 30 odd years ago. We had to shift it 20 yds then change direction for the 80 yds up a slight incline that felt like pushing a truck up Ben Nevis. For anyone who has ever moved machinery of this scale they will know that if you are faced with the merest of incline the weight feels like it doubled! The previous owner came to the rescue with an old tractor that helped us pull it out. You do some thing's once in a lifetime and for me that was it!
The last pictures posted showed the machine fitted with two Pratt Burnered 4jaw chucks which can be changed for the original adjustable throwblocks that allow for offseting the crank. I have included some pics of these and a brochure picture of Churchill's Self centring chuck set up which was fitted with indexing 3 jaw chucks, these are what I would rather have as they would allow for a much quicker set up time. If anyone out there knows of a pair, let me know? The main journals would be ground on the MT5 centres that came with the machine.
Another interesting feature is the ability to taper grind up to 9 degrees, the top table swivels on a hardened steel stud and the taper adjustment is controlled by the screw at the end of the table. However, one would need to remember to reset the table back to 0 then clock the work before grinding recomences!
As soon as I have it running with a crank I'll post a video.

Thanks all for the comments & support.

Kenny G



]


Kenny G

[oil mac]

Bleeding Heck!
Someone installing a nice big machine tool in south West Scotland This to us all in the South of Scotland is a breath of fresh air for a change

Congratulations &best of fortune with your machine

Dan.

[Kenny G]

Please excuse me as I am new to all this forum & posting stuff and not sure if I am replying correctly? In answer to Black Moons post:
Why would you need to do offset grinding on a crank shaft?
I could see cam shaft sure, But a crank shaft?
There are a couple of benefits in using an offset grinder over a follow round type.

1/ The ability to grind the pin concentrically to its original position.

2/ Being able to adjust the stroke is another major advantage for me.

Kenny G

[Kenny G]

Dan

Thanks for the words of encouragement!

Kenny G

[hareng]

Glad you have rescued a decent machine we used to have several Churchill grinders but mainly Snows.
Intrigued by the lumsden which was the biggest machine we had needed a couple of steps to get up to it.

[.RC.]

Nice machine..

Spindle is on hydrostatic oil bearings, allow it to run and warm up for 1/2 hour before starting work or you will get flats all over the journal.

That is one of the reasons I have shied away from getting a cylindrical grinder.. To get the accuracy the machines are capable of you have to warm them up... You also need to use coolant which for my use, the coolant would go off between uses...