Wide Guide or Narrow Guide?

Has anyone converted their ML7/Super7 from narrow guide to wide guide
on the shears? Any opinions? I'm pondering the change while I have the
saddle down for re-grinding.
Peter
Reply to
Peter Neill
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Peter, This is the Martin Cleeve thing from half a century ago. I did it to an old Super 7 years and years ago. The idea is simple enough as the No4 shear is- or should be unworn. Mine had mill marks!
The next incursion was a friends's ML7 which I wrote up in MEW years ago-in a Postbag article. I think that people will be fed up with me prattling but with say 6thous removed, I had a reference and handscraped a strasight edge to do the front- number 1 way.
If you think about it, the Cleeve(?) system uses the Numbers 1 and 4 shears and is theorertically longer than the central- now worn guide- and has therefore better wearing length and with the addition of gibs at the rear and a gib, you can swing the saddle about to get the slight concavity.
There are a lot of additional factors in this but I am sure that I don't want to elaborate but for other readers, the question is that despite the improvement to the bed, other wear to the saddle, the topslide, the leadscrew and a host of other wear points will exist. You may want to settle for an improved rather than a "new" lathe again.
You have my E-mail address to get my home phone number if this will help.
Norman
Reply to
ravensworth2674
I did it to my ML7 whilst I had it apart for a bed re-grind by Myfords and a saddle re-scrape by me. I used a bit of 1/2" x 1/32" shim from J&L fixed to the rear inside face of the saddle with super glue. That face of the saddle produced just marginally concave facing with the shim fitted, but I wouldn't guarantee that you would get that result without some scraping on more than 50% of saddles.
If you use something that sets a bit slower, say Loctite 603, and work reasonably fast, it should be possible to fit the shim to the back of the saddle with the Loctite and adjust the front gibs to get concave facing before the Loctite has set.
You will have to grind/shape/file-scrape the leadscrew bearings to allow for the fact that the apron is now further back than it was when it left the factory (don't assume that there is enough clearance in the mounting screws- there isn't). This isn't a major job though. You would also need to do this if the bed were re-ground. If you could use 20 thou shim on the saddle, you could exactly compensate for the amount that Myfords take off when they re-mill the shears.
As to whether it is a great improvement, I'm not sure. Previous owners had left my lathe's saddle like a rocking chair and the bed like a ploughed field, so anything was going to be an improvement.
One mod that I would recommend, that I'm not sure if Messrs Cleeve/Sparey et al have come up with is this:-
Drill and tap for a couple of studs though the tailstock clamping plate to the base of the tailstock, say 1/4 BSF. Then fit a pair of studs, washers and locking nuts to limit the amount that the clamping plate can be loosened. I can see no reason why there should be more than 1 thou of clearance on the clamping plate at either end, preferably half a thou. One reason for this is so that the tailstock can be slid on the bed with a small drill or tap in the chuck and not need a lever operated slide. The other reason is to make it much less likely to accidentally trap a piece of swarf between the tailstock and the bed.
I haven't done this mod yet, but intend to do it to my ML7 when I fit the new tailstock base prior to selling the lathe and to my late father's long bed ML7B when I've finished refurbishing it.
Mark Rand RTFM
Reply to
Mark Rand
I am indebted to Mark. According to my records, Ian Bradley was not involved in such things but he did do an article or two on scraping. Tubal Cain did a sort of write up and Jack Radford raised similar problems on his Super 7. However, Martin Cleeve actually raised the height of his ML7 by a Quarter of an inch and described it in ME, together with with a quick change into and out of back gear. Another mod is his Skew rack tailstock described in July 1956.
What must be remembered is that Cleeve also made a lathe from bar steel. Sadly, he didn't get on with Thomas and Co and we are now the losers.
I do, surprisingly, have most of the ME's with his write ups. I always wonder whether they will be more acceptable nowadays. For my ML7, I wonder if there are cheaper means of getting a new/reconditioned spindle and bearings for my ML7. Any ideas,please.
Norman
Reply to
ravensworth2674
Norman and Mark, thanks for your thoughts on this. I've decided to stick with the current narrow guide for the moment and concentrate on getting the lathe back together for now.
I completed the fixture for holding the saddle on the grinder this weekend, and I've just finished grinding back the saddle, saddle strips and gib strips. With the prior condition of the saddle bearing faces (your ploughed field was an apt description) I was pleasantly suprised to find that only taking 0.007" off did the trick.
If I get another weekend pass from the family to work on it I should finally have it running again.
Peter
Reply to
Peter Neill

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