Perris SL90

[Frances IoMParticipant @francesiom58905]

[Frances IoMParticipant @francesiom58905]

I recently acquired this small lathe – looking at http://www.lathes.co.uk I think it is an early model of the SL90 – no back gears however but has box to add dog clutch – judging from lack of any paint suspect it is a self assembly model – it came with a reasonable set of tools – the base for a small saw table can be seen. (the socket head on the tool post is not original!)

it also came with this collet holder and a few collects – is this a Perris special

The tailstock is a truncated MT0 which judging from absence of any other supplier is also a Perris special

the other end of the drive has what appears to be a 1/2" 26tpi + 3/8" ? 26tpi – any confirmation would be welcome (two threads for which I don't have taps or dies)

the tailstock is locked by what appears to be a 2 BA screw (somewhat worn in places) – angain any confirmation + additional info especially on the various other threads welcome

I have seen the info on lathes site but £45 for some reprints that may not add much info is almost what I paid for the whole package

[Michael GilliganParticipant @michaelgilligan61133]

Nice find, Frances

Some [albeit not that many] similarities with my 'Jason' lathe, which was also designed by Brian Perris.

… The dog-clutch would be a useful addition.

The mandrel rear screwthread on the Jason is 1/2" 20tpi [unified], which was a surprise. So I can't help with yours.

What does really interest me is your collets … The Jason nose is bored to take them; but I don't have any.

… It would be a great help if you could let me have the collet dimensions, sometime.

MichaelG.

 

 

Edited By Michael Gilligan on 01/05/2016 20:06:24

[Frances IoMParticipant @francesiom58905]

all in mm
length 21.5
at inner end OD 12.7
bore 8.2 for 12.7
OD drops to 12mm after 6.3
flex end OD 15.4
ID largest 5.2
suspect they may be for centre drill + small 1/8th shafts – they don’t appear to have much range + I suspect one has been forced too much as seats totally into holder

I have a mandrel MT0 to the 20tpi 1/2″ thread on inner end of holder

The motor is a 1/4 hp (approx) made 1971 with reversing switch but on a hinged plate so that motor weight aided by a spring tightens the belt (would have expected a 5mm circular but uses a flat toothed belt (as also does one illustrated on lathe site

haven’t tried any cuts yet but motor (even uncoupled) seems to have some 1second period vibration

[Michael GilliganParticipant @michaelgilligan61133]

Many thanks for the prompt reply, Frances

Unfortunately: it is now clear that the collets are not the same.

… Very much appreciated though.

MichaelG.

[michael pottsParticipant @michaelpotts88182]

Hello Frances.

I missed this thread when it first appeared.

The spindle threads are 1/2" X 26 TPI and 3/8" X 32 TPI. These threads still exist on the Cowells ME90 lathe spindle.

The collet in your second photograph is a Perris design. There were four standard sizes, according to the brochure, 3/32", 1/8", 3/16" and 1/4".

There should be two threaded holes to the rear of the LH tailstock bearing housing to fit the backgear bracket. From memory they are 10 – 32 UNF, but I would need to confirm that. The tailstock locking bolt could also be this size. It is close to 2 BA, but that does not work properly.

The spindle and tailstock tapers are 0 MT, truncated. Cowells still have them, and are a source of centres that will fit without taking up too much space.

The lathe was available as a number of variants, the plain lathe, which is the model that you own is the basic one. Owners could add backgear and fine feed with the dog clutch to end up with the version seen in the brochure. Screw threads are a complete mix of BA, UNF / UNC, and imperial. Cowells metricated everything virtually as soon as they took over.

You do get the impression that Brian Perris was living from hand to mouth, but the machine that he designed is still in production as the Cowells ME90 machine, forty years later, which says something for his ideas.

If you have any further questions please ask.

Michael Potts.

[Frances IoMParticipant @francesiom58905]

Thanks Michael – I’ve made the dog clutch but needs a little more to finish it off once I return to UK – decided to make a new Perspex coverplate as one intention is to use lathe as a simple demo lathe and thus people can see immediately how it works – will check out the #10 UNF – don’t think I have taps/dies for this – I did cut a new 2BA and that seemed to work but recall it was a little loose which I put down to wear (as you say a right mixture of threads – maybe best logic was that he used what he had available! – 6mm + 1/4″ also seem to be a random choice) – I’ve started to replace the handles with brass (to match its new paint job in GWR green) which allowed some small thrust bearings on leadscrew – I suspect the tailstock handle has been thumped in storage as the cheap looking ali handle was broken and there is some slight catching as though tailstock screwthread is slightly bent.

I looked at Cowell’s prices! – suspect I’ll do without the gears unless I can get enough 2nd hand + not think of screw cutting though tempted to had small stepper motors to cross slide + leadscrew so can cut small tapers etc and as neat demo of CNC

Maybe we can swop ideas ?

[Author]

Posts