Member postings for Dennis WA

Mike .....thank you for this useful feedback. My S7 is running very well on the low speed range with all bushes and bearings at room temperature. On the high speed range only the countershaft bush next to the clutch gets hot when running at the 2 highest speeds.

I am still going to fit new Oilite bushes and will post the outcome.

Regarding heavier oils, Bromor make oil impregnated bronze bushes that require one to soak them in SAE 100 oil for 12 hours if you have machined the bush.

Bromor state that:

During manufacture the bar stock is vacuum impregnated with oil to a level of some 18 % (by volume).

The oil is supplied to the shaft through thousands of interconnected, oil-impregnated pores.

Due to capillary action present in the material, the shaft is wet with oil, whether in motion or not.

An immediate oil wedge is always present when the shaft is in motion, assuring proper lubrication at all times.

Dave

Thanks for your explanation.

The bush fitted by Myford is an Oilite which is pre-loaded with oil and supposed to last for a long time (Myford ask that you keep the oil cup topped up as needed). My Oilite bush currently has 1 thou clearance from the hardened steel countershaft which is indeed highly polished. The bush is not highly polished, but the bearing surface is in reasonable condition. The 2 countershaft bearings and their associated ball thrust-bearing are going to be replaced.

Hopper

There is no belt slip. The clutch is not slipping either.

The S7 is running extremely well, silent and very smooth except for the countershaft bush getting hot and pushing out oil. This occurs as 1. bubbles blowing out from the oiler and 2. leaks from the ends of the bush.

The bubbles effect has been reported in this forum a number of times but no one has explained what might cause it.

The bubbling and leaks start while the bush is still cold. It is almost like the shaft is running in an eccentric bush and acts as a form of pump. As the bush loses oil, friction increases and heating occurs. Adding oil achieves some cooling. So I currently need a total loss lubrication system!

The problem is really evident at the high speed setting (740 to 2105 rpm) - at the low speed setting (210 to 600 rpm) the bush hardly gets warm. At 2105 rpm it reaches up to 70 deg C within 5 minutes.

The S7 is usable within these limitations for the work I do. New bushes and thrust bearing will be fitted.

Thanks for your interest.

Hopper

Thanks for your pointers on the H frame.

I have a good length of 7/8" bar which I used to check alignment when I was doing the countershaft test yesterday. The 2 bushes were perfectly aligned.

My S7 was in very good condition when I bought it in 1991. But your comments are a good warning to buyers.

Dennis

I ran the S7 with the stripped Countershaft only connected to the motor with the clutch operating lever removed. The belt had sufficient play. The countershaft has 2 thou smaller diameter than the ID of the oilite bushes.

For each test I first removed the countershaft and lubricated both Oilite bushes with the correct hydraulic oil. I then repeated this test but with an automatic transmission oil containing Molybdenum disulfide

The large bush still got very hot (70 degrees C) within 5 minutes when the countershaft was running at high speed, but just warm when running at the slower speed. The small bush remained cool throughout.

The next step is to replace the bush.

Thank you for the feedback. The bush continued to get warm within a couple of minutes without any distressing noises, so more investigation....

The bush was getting oil, but via a passage from the oil cup that passed through the bush directly onto the spindle. The smaller bush at the clutch lever end was fed in the same way. I thought that oil was to be passed through the Oilite bushes to the shaft?

I removed the countershaft today and found both bushes to be acceptable, whilst the countershaft was in excellent shape. Critically the small bush and the portion of the shaft in the bush showed enough oil to be well lubricated, whilst the large bush and its portion of shaft lacked evidence of much oil, even though I had pumped 32 hydraulic oil though the passageway.

I had also slackened the drive belt tension from that recommended by Fenner.

Measuring the countershaft showed its diameter to be 0,8750". The front bush was 0,8775". Is that the correct clearance?

I have just fitted taper roller bearings to the spindle of my 1981 S7, which I bought little used in 1991. I also fitted a Fenner drive belt to the spindle / contershaft . Finally I fitted new bearings to the electric motor. The clutch and countershaft assembly, were checked and found to be in good order and free running. The S7 is running smoothly and the spindle turns freely without play. Two rings on my test bar were the identical diameter when machined.

The headstock bearings run cool, as does the drive motor and the countershaft bush next to the clutch lever. However the bush next to the clutch runs quite warm reaching 45degrees Centigrade. The 2 drive belts have a small amount of play.

All components are correctly fitted to the countershaft / clutch. They had not been opened since 1981! This lathe has always done light work, as I have a Colchester Student in good condition for the bigger jobs.

Should I look at replacing the bush?

Thank you for any advice you have.

R.I.P. Sir John

My sincere condolences to his family.

Dennis

John ...who is going to control the Chinese machine tool industry's advance ? You need to develop your successor in both technical and linguistic skills! Besides, the legions of clumsy bastards still need to be sorted.

I have followed John's posts on a variety of technical forums over the years. I respected his practical solutions, enjoyed his apprenticeship memoirs and our one face-to-face meeting.

Dennis Johannesburg

"Presumably by "crescent wrench" he means C spanner."

That is what I thought. Martin can correct us if needed!

Cheers

Dennis

Bill....Taken from this Forum, but I cannot find the post: apologies to the original poster(s).

Thanks for the answers.

It seems that, subject to your lubrication working, getting temperatures up to say 50 degrees C when working hard / at high speed are possible.

The trick is to feel how hot the headstock becomes when working under these conditions.

For the benefit of those who may not know, "the Gospel according to Malcolm" is the setting up procedure for the Myford Super 7 headstock & spindle assembly. Malcolm worked at the original Myford works in Beeston Rd.

How warm should the headstock (chuck end) get running at the higher speeds? My S7 gets warm to the touch at the chuck end - around 30 deg C measured with an IR thermometer. It is set up following the manual and using the Gospel according to Malcolm.

What was the bridal party doing in the River Don video?

Thank you Richard.

Despite their price, I use Reilang oil-cans. Like many other folk I have found them to be the best!

Dennis

Richard,

You posted: "I have made Brian Forrests designed nozzle for Myfords and it works a treat."

Where can I find details of this nozzle?

Thanks

Dennis

Jonathan,

In 2012 Darren Boden's phone number was advertised as 07790364189.

Cheers

Dennis

Thank you Steven for the link and Gordon W for the confirmation.

Dennis

This "folding hook" made by Smiths of Saltley (the Snail brand tool makers) came from a deceased ME's workshop. It is 7" by 2". More pics in my album.

Can anyone advise what was it originally used for?