Jakobsen SJ 12 Grinder.

Good morning everybody. We have had one of these machines for more than 30 years and it has been a real bobby dazeler. Reliable and accurate and easy to use. However over the last few years it has developed leaks from the hydraulic piston seals and from the oprerating valve packings. Since this started it has been sitting in a pool of leaked oil looking most forlorn. It was however fully operational and all that was needed was rubber boots and a boiler suit to operate it.

Well as we are not so busy at the moment I set to to repair the old girl. I sourced the piston seals and made new packings from polyurethane and rebuilt it. The hydraulic system now performs almost flawlessly I say 'almost' because the one system that I never touched; the cross feed circuit, now refuses to work. All the other functions including the hydraulic micro-down feed work perfectly but the table will not move athwartships under power. The manual system is perfect. There are now no oil leaks so I can only conclude that there is an air lock in the affected circuit.

Can any of you with hydraulic expertise which I definitely do not have, sugest how to eliminate air from the system please?

Charles.

Cross feed circuit

Familiar story, to my old Thompson surface grinder. Drain it's oil sump and change filters and the foot valves leak down and we get the same story as you've got. Only solution seems to be "let it run"...given about 45 minutes and it sorts itself out.

Cyclotronguy

Cyclotron Guy,

That's what I am doing for more than 5 hours now, but still no change yet.

Charles.

Hello Charles and the forum in general , this is my first post. I have a Jakobsen sj 12 . It works perfectly except for the incremental feed the very same problem as you have got . I was on to Jakobsen in Denmark and they were not interested to say the least. I am also looking for a manual for this machine .If any one has this in PDF format I would be glad of it

Downloads - Deckel NC Milling Machine Web Site

At above site you can find the scan I did from my SJ12 manual (in german).

Martin

sj 12

Thanks Martin p got that

Hello again Charles. I finally got around to fixing the SJ12 today. It was a stuck spool valve in the cross feed valve chest. You will have to take it apart, it is pretty easy to do . The hardest part is opening the hydraulic lines from it. I found the fault after I looked at the manual that Martin P so kindly scanned up for us. It's on page 16 , there is a small spool valve with a coil spring in the middle , this had seized, a light tap with a plastic mallet shifted it. Got it back togther in an hour works perfectly now. hope this is of some help, Mikeh935

I have a problem

Martin P said:

Downloads - Deckel NC Milling Machine Web Site

At above site you can find the scan I did from my SJ12 manual (in german).

Martin

Click to expand...

Hello Martin and the forum in general, I have a problem with my Jakobsen SJ-12.
The rapid switch to up and down the grinding wheel doesn´t work because doesn´t have the motor that makes that function. I saw the manual but I couldn´t find nothing referent to mi problem. The machine works very well but is dificult up and down the grinding wheel manually. I know that is dificult find spare parts for this machine but I want to fix this problem the problem is than I don´t know what type of motor use to resolve the problem.

Dear all, I have the same model ( jakobson SJ12 ) , I wants to replace the vickers vane pump ( fitted on hydraulic power pack ) , but unfortunately its with out label, can any one help me to tell the pump details to run the machine , ( pl ref manual -page 23 item no 823)