Member postings for DMR

Ah,

So the issue number has gone off the front. No wonder I never found it in newsagents! Just to see if it was of any interest you understand. You may gather I lost interest.

Edited By DMR on 03/11/2013 16:35:15

You could try the screwdriver (or other rod) test to try and determine which end the noise is coming from first. One end on the mandrel and the other end hard against the back of your ear.

It is known that if the mandrel got really hot, as in heavy loading, the felt wick melted and tended to glaze over. Most likely to happen when drilling or using the tailstock for between centres working. It also tended/tends to wear a groove in the mandrel under those conditions! A possible test you could try if all else fails is to release the rear bearings off and stick some oil directly into the front cone. Reset the bearings and try some "noise" production, even applying a bit a bit more oil to the top of the cone outer surface. If no noise initially, then it's that wick

To examine the wick assembly, you have to separate the head from the bed. Removing the mandrel alone allows the wick to protrude into the cone bearing centre, but you should not then attempt to re-assemble/reinsert the mandrel, pushing the wick back in place as you go as this action will most likely just bend/destroy the wick.

Mike,

There is no need to complicate your life thinking you need different thread-cutting abilities with the early gearbox. There is a times (x2) involved, and that is all the info you basically need. The cogs at the left side between tumbler and gearbox input are identical to the later model. We have conversed on this last summer and looking back I see that I failed to reply to one of your mailings as you dropped off the bottom of the visible list. Sorry.

I have sent you a PM with my e-mail address and can supply all the tables/diagrams and any other info you need.

Dennis

HI Jamie,
Your older S7 clutch should not need constant resetting. I would suspect that you have the same problem another chap had on here some 2-3 years ago. The adjusting screw inside the pulley wheel should have a second screw in the same hole acting as a locking screw. It is 1/4inch BSF which may be a problem to you, but I can sort one out if that is your fault/problem.

As to fitting a modern clutch, it is not all that sinister but it will cost you if bought new, and if you could obtain what you need. The new Myford owners in Halifax (RDG) do not advertise a complete-er assembly which is what you would need. The big danger in buying second hand is that you cannot tell if it is OK until you can fit it. Bushes and bearings wear out, but RDG have those. However, as the previous postings you refered to earlier, the bearings are difficult because of the powerful spring in the countershaft.
You cannot just buy a new countershaft with clutch and (different necessary) pulley, which RDG do advertise. In addition you would need the complete cast iron rocking assembly (which RDG do not have) that the newer clutch sits in including the clutch engagement lever and all ancillary bits on the rocking assembly.
Two covers would need modifying in addition. The primary belt guard outer cover would need a circular cutout (or a replacement inner and outer cover) as the modern clutch needs more space. And the secondary belt guard (lift-up cover) would need a modification to the countershaft cutout as the rocking action shifts a bit and the casting is a bigger diameter over the shaft. Note that a newer cover here is no good to you as it will not fit over the mandrel drip-feed oiler arrangement.
The lower casting carrying the motor - what Myford called the Countershaft Arm - is identical between old and newer machines. Do you have the Myford diagrams for your early assembly?

Dennis

Edited By DMR on 23/01/2013 21:44:26

Edited By DMR on 23/01/2013 21:48:08

For jwb, Michael C, and anyone else with S7 clutch problems

Quote from jwb:

"Could you go in to more detail on this please? My S7B has a problem with the cone clutch - running out of adjustment at the outer nut/slotted end of pushrod, noisy operation - and from examination of the parts catalogue and the manual I have suspected that what you describe would indeed happen, and clutch bits would disappear to remote corners of the workshop if I attempted to dismantle it.
Yours sounds like the voice of bitter experience! Any practical advice on dismantling this box of tricks, please? Can you describe the spring compressor?"

Sorry jwb, but I but I do not live on the internet. I only log on every couple of days or so.

You both need the two bearings at the right hand end of the countershaft. I can only assume that Eddy Spriggs method above works. I was lucky to get mine done as part of a bed regrind by Myford just before they went down (very sad).
The problem is the spring inside the countershaft. Uncompressed, it is about twice as long and very strong. Any compression device for it would need to be 500-600mm long minimum having a long and powerful compressing action, long enough to get the nuts on the end into the right position, which is with some thread of the pushrod sticking out beyond the locknut. It would also need a big bow to fit over the pulley/clutch end

The push rod can be adjusted as in Ian Bradleys book with a screwdriver in the slot at the end of the pushrod and the nut released, but this must only be considered as a fine adjustment aide. The push rod should never be rotated against its spring any more than can be helped as the action will create swarf inside the assembly by the ends of the spring rubbing on the countershaft shoulder (at the left end ) and the pushrod head (at the right end). It really is that compressed - it does have to prevent the clutch slipping remember. It follows that it is not on to get the pushrod just started (not that I can see anyone would manage it by hand anyway) and wind the rod in the rest of the way. If you try any adjustment before attempting disassembly, you will understand.

Sorry I cannot be more help. There really is no practical advice as it depends on your facilities. Not that it helps, but Myford replaced the bearings in minutes. It sounds to me like jwb may win with Eddy's method, but the clutch should not "run out of adjustment" unless there has been clutch slip wearing out the cone. If you have noise, then you have bearing trouble, but you may need other parts as well. Michael will need a total stripdown anyway as the bearings are sealed-for-life type and he has introduced all sorts of foreign bodies in his "cleanout" where he cannot get, round the spring and pushrod area, and his clutch action will never be smooth or noise free.

Good luck to you both, and to anyone tempted to release that pushrod without restraint. Such action would be very dangerous to skin and bone!.

Dennis

So "hi, Its Michael, ". Strange psuedonym then, but never mind. Perhaps it's Terry's machine.

Seems like NJH is sorting you out away from the crowds. No bad thing as it seems you need a Myford manual copy and some personal help. There is some good news. With the serial number on the back, it should mean your bed has never been reground should it need it, and would come up like new in the right regrinding hands, if you can find any outfit to do it.

Your serial number is in a form SK123456, always SK if the bed started life as a Super 7 one, and up to six numbers. 71/ might be the SK, but you cannot have number 110413 as such a high number was never on the back of the bed. Even if it is as low as11043 it is the modern clutch.

However, I now realise that you are talking about gears and gearboxes not being stopped by the clutch. Does the mandrel stop with clutch action? If it does then there is nothing wrong with the clutch, but NJH seems to be onto your problem. My main concern in getting involved was you releasing that nut as previous mail and doing someone a mischief.

Dennis

First question is are you a Terry or a Michael?

Next question is does the clutch operating lever flop about, or is it stuck fast in some position?

There are two S7 clutches. Early answers assume you have the later (post 1956) version, so what is the serial number of your machine?

On no account at this stage release the central nut on the end of the modern cone clutch (as implied by early answers). You could have a push-rod fly across the room, and you will not be able to get it all back together without a fancy (special) spring compresser.

Dennis

Mike,
Your efforts are certainly impressive on this.

There is no wick down the oil hole in early drip feed machines!

Earliest countershaft/clutches ran on needle roller bearings and that is how you have picked up on the noise aspect. Yours clearly has had the bushes retrofitted at a date after manufacture. It was a Myford offer for all the early machines which became noisy; but not a free offer. A noisy countershaft would still work fine with no noticeable play, but sounded awful.

Dennis

Mike Mc,
I have the 710th production S7 and a more modern one. To my certain knowledge Myford never fitted motors with 1/2" shafts.
I would have to agree with Mike that it has been changed along with the pulley. What does the motor plate say as to manufacturer? Might give you a clue.

Sparky Mike,
The belt sections are different. Countershaft to spindle is A29 1/2 (A29 and a half). Motor to Countershaft is M32 1/2.

FYI early motor pulleys were alloy but at some point an iron one was made available as a spare. The small (inner-slow speed) tended to wear out rapidly.
At some other point or maybe the same time, Myford began fitting iron motor pulleys as standard.
Later still, probably when stocks of alloy pulleys ran out, Myford announced that they would no longer supply the (cheaper) alloy pulley. At a guess, that was before the year 2000.

Dennis

Mike,

You are not getting the full story. So before you get in too deep......
In no particular order:
1. The last gearbox of the type you have was Serial No. QC (for Quick Change) 2500. QC2501 was the first "modern" one.
2. It is thought that many early gearboxes were retrofitted in the factory with hardened cogs, but no records were kept. Also quite possibly from some point before QC1950, hardened cogs were fitted as standard.
3. The leadscrew on your none-gearboxed machine has quite probably got a different plain diameter at the headstock end, as in smaller than what you require.
It must fit the hole in the gearbox casting closely for obvious reasons.
4. It is somewhat trickier to align the gearbox with the leadscrew, but it must be done and done carefully or the hole in the casting for the leadscrew becomes worn. The "modern" box is almost self aligning as it goes right through, but it still needs doing.
5. To align the gearbox properly, you need a spacer strip between the gearbox and the top two fixing screws along the bed shear. It is just a flat strip with two holes in, but I have no idea what the thickness is. That is a left over from the earlier ML7 fitting.
6. Your gearbox runs at half the speed of the "modern box" to cut the same thread. That is to say, your output gearing at the right hand end is 1:1, whereas the modern box is 2:1 at the left hand end. There is no chance of you altering the principle to be the same as a modern one as you won't make it fit!
7. A consequence of this that you also need a 12/30T FINE FEED TUMBLER GEAR A1974A/1 as it is termed on the Myford/RDG website to drive the standard fixed quadrant geartrain. The modern box uses 24T/30T and hence does not have to be a combo cog.
8. Do not try and use the Myford modern screw cutting details as in a later manual as you will end up with a times 2 factor as above, but you can do far better none imperial threads than the earlier Myford tables.

9. The guts of the boxes are identical and interchangeable apart from the shaft differences of course

Think that's it.

You have some way to go to get going.

Dennis

Barney,

It's not that simple. It's 24T if your gearbox is after serial number QC2501. Before that it was 12T consisting of a 30T/12T combination which is now sold as being for the ML7 only!

Gearboxes prior to QC2501 had different external gearing and an aluminium cover on the right hand end of the gearbox.

Dennis

Edited By DMR on 16/12/2011 23:56:15