Perris PL90 rebuild

[Speedy]

This is not a rebuild log, as I did not take any photos as I went along, but now I've nearly finished it occurred to me that some of you might be interested in some of the mods and alterations. It's not a Quickie Machine Modification either as I've been tinkering with it for most of this year.

Towards the end of last year I was looking for a machine to fit the bill as a house lathe as Jo has described in another thread. I wanted a Cowells, but could find nothing except a little Perris PL90. As far as I can gather these are identical to the earliest Cowells lathes. There's some more about them on the lathes.co.uk website http://www.lathes.co.uk/perris/

This one was in South Wales, which turned out to be a six-hour round trip to look at it. It wasn't in very good shape (and I didn't check it over as thoroughly as I should have done). The seller wouldn't budge on price and having driven so far and used so much diesel he had me over a barrel really. But I decided it was viable as a project in itself, it came with some tooling, he had some useful extras, we agreed a good price on those and I brought the lathe home.

The only "before" photo I have is a blurry shot emailed to me by the seller.



There's a lot wrong with it. Starting at the top, the countershaft hunted freely from side to side. And rattled because the bearings were shot. The pivot at the base of the countershaft bracket was worn and the whole assembly did not match the paint finish on the lathe. The paint on the lathe was old, tired and chipped. The mount for the backgear was crudely finished and crooked, which meant the gears were out of line and did not mesh correctly. The brass bearing for the shaft looked to be a replacement and wasn't long enough. The main problem was extensive play in the headstock bearings. Once I stripped it down I found the spindle was badly worn at both bearing points and after some experimenting with a 1/2" ground rod, it was apparent the left-hand bearing was worn too. The oil pots were mismatched and crooked. To the right you can see where someone has broken a chunk out of the cross slide T-slot and brazed it back in. The toolholder was home-made and bent out of shape through overtightening and the stud had been replaced by an 8mm hex screw. This screwed into the original mounting hole for the stud, which was tapped crooked. The quadrant was badly designed and finished and the mount for the lead screw shaft going into the clutch housing had been butchered to give the clutch slide sufficient clearance. The handles on the leadscrews were old-style, parts of them had been crudely remade and marked and they had no zeroing capability. The motor vibrated, was solid-mounted and noisy. The whole thing was mounted on a crude plywood box. There was more, but that'll do for now. I hope you're with me on the terminology, by the way. I'm self taught and still learning what all the bits are called.

So on the surface, it looked like a complete disaster. On reflection though, it's not as bad as it seems. The bed and the headstock are fundamentally OK. There are a lot of fabricated parts, which, when stripped down, are very simple to replicate. Mr Perris's workshop was apparently equipped with only basic machine tools, and I liked the idea of a project on which I could learn new skills. I'm pretty much a beginner at working with metal, but the work required was not complicated. The only thing I really needed was time, and I've got plenty of that right now.

This is how it looks now. I've still some tweaking to do, but it's almost there. I am also refurbishing and augmenting the tooling that came with it, but in the way of these things, I've started all of it at once and none of it's finished yet .



More details to follow shortly.

Pete

[Don1966]

You have done a great job on it Pete. Did you add the control box to it? Do you have threading tools for it and a vertical slide? I would like to see some of your extras.

Don

[Jo]

Looking good. I see you have added the double speed layshaft pulley. I knocked up one for mine, but have not used it yet. I was not sure if the bearings might over heat.

The handles are interesting, you seem to have the later Cowells ones.

What is the spindle nose thread? 14 * 1.5mm (as per mine) or the earlier 1/2" thread?

Jo

[steamer]

That's a little beauty!

Dave

[steamer]

Rudy Kouhoupt found his Perris was suffering from similar problems and ended up making a new spindle.
   

[Dan Rowe]

The handles on the leadscrews were old-style, parts of them had been crudely remade and marked and they had no zeroing capability.

Pete,
Did you make new handles with zeroing or did you get them from Cowells? I need to upgrade mine with zeroing.

Dan

[Speedy]

Thanks for the kind words. I put together the control box.



The bits came from Maplins, the UK equivalent of Radio Shack. http://www.maplin.co.uk/eddystone-die-cast-aluminium-shallow-lid-thin-wall-43713 It contains the motor start capacitor, the switches (obviously) and the original wiring.  It's mounted on a crude simple bent steel bracket. I drew up the graphics in Adobe Indesign and printed an inkjet copy which the local copyshop laminated for me. Cut it out and stuck it on with double-sided tape. The Perris name is in a typeface which Perris themselves used at one time when labelling their machinery. It's Copperplate Gothic Bold, for anyone out there who is as obsessive about such matters as I am.



I made up a plate for the motor to sit on, complete with adjustment facility, but I think that was overkill. If I did it again I'd just bolt it to the base. I used some rubber isolators which make a big difference to the noise levels. The motor vibrates, but in an axial plane (I think I've got that right). At the centre it's almost vibration-free, but the further out you move from the spindle axis, the more vibration is apparent. I don't know if this is typical of this type of motor. Now it is rubber-mounted it runs smoothly enough anyway. Everything was primed and sprayed gloss black with rattlecans. I don't much like painting but it looks OK.

I have a Cowells vertical milling slide for the lathe. It was one of the extras the guy was selling separately, along with a complete replacement carriage and cross-slide. I know how much Cowells charge for those and he was asking a very reasonable price for them, which was the clincher for the deal really.

A set of changewheels came with it



together with a four-jaw chuck, fixed and travelling steadies, a shop-made tailstock lever feed and a faceplate.

That's all the threadcutting gear I have, but I'll be grinding up a set of HSS cutting tools in due course.

I am also making a Cowells-style filing rest, quick-change tool holders, a catchplate and lathe dogs, a selection of 0 morse taper centres, an 11mm ER collet chuck and one or two other bits and pieces which I can't quite bring to mind. It's all scattered around the workshop right now. I'll post some pics when I've got something presentable to show you.

Pete

[Speedy]

Handles I made myself. They are in the same style as the Cowells ones, but not direct copies. I had to make up the zeroing bit anyway as I had no reference. The sharp-eyed viewer will notice that I haven't stamped any numbers on the dials yet. I need to make up a jig to hold the punches to get a tidy result. I have done this sort of thing by eye before, but they were a bit scrappy. I have fitted thrust bearings in both directions to the lead screws. Maybe overkill again, but it does make everything very smooth; you can tighten up the gibs which reduces play and tighten up the end screws which reduces backlash. It was straightforward to counterbore the handles to take the bearings (12mmx4.4mm, 6mm hole) but I had to make new aprons with a greater vertical dimension to fit them there. I couldn't do this on the original topslide as the apron and slide were in one piece. The topslide was a problem anyway. The stud for the toolholder was off the vertical which meant the toolholder would not sit flat on the top surface. So I made a new steel topslide. I forgot to engrave the index marks when I put everything together, so I'll have to take the aprons off again when I stamp the dials.

The cross-slide and carriage deserve a mention. The replacements were still in their grease coating, but the apron did not fit either of them properly. The original cross-slide had clearance holes through which countersunk screws passed down into threaded holes in the apron. The new slide needed clearance holes in the apron for screws to pass up into threaded holes in the cross-slide. I couldn't just drill out the threads and countersink to take the old screws, the new holes were further apart, so I had to drill out the apron holes and then enlarge them to slots to fit the new slide. While I was messing about with the apron, I found excessive lateral clearance between the leadscrew nut and the apron, so when it went back together I managed to slide in a 0.15mm brass shim to take up some backlash.



The main leadscrew got thrust bearings as well. The handle side was simple, but I couldn't machine the bed casting to install one there. I made a replacement bush. It's 2mm larger in diameter and 2mm longer to accommodate both the bearing and the grubscrew. I turned 2mm of thread off the leadscrew so everything fitted, which I thought was a small price to pay.



The handle on the tailstock is not fitted yet. It needs a longer shaft to fix to, which means turning a new screw for the barrel. 6mm L/H thread. I will probably make a new barrel while I'm at it. The original base for the tailstock was crudely made, inaccurate and fitted the slotted bed very badly, so that got replaced too.

The listed top speed was originally 880rpm which seemed slow for such a small machine. I designed the new pulleys to give a 2100 top.



Something went slightly wrong somewhere as I intended the belt to have the same tension when swapped over from one to the other and it's turned out a bit looser on the high speed setting. It works OK though. I've only run it for 5 minutes without load so far and the bearings did not warm up in that time. The problem is at the higher speeds it flings oil all over the spare bedroom, so some house-training is in order before it gets used in anger. The old countershaft bearings were (I think) oilite bearings. There was no facility for lubricating them at any rate. I turned replacements in PB and once they were pressed in added some oil holes as well to be on the safe side.

The headstock spindle was a major issue for me. The original was unserviceable without running the risk of snapping the headstock casting. I knew it was hardened and ground and the idea of making a replacement myself was daunting. However, after speaking to Cowells, I found that for the cost of a new spindle I could buy enough freecutting mild steel to make 81 replacements, so thought I'd have a go. Mine wouldn't be finished in the same way as the stock item, but if I took care, I should be able to make it accurately. If I failed, or if the new one wears out, hell, I've got enough steel for 80 more.



It went OK. Turned between centres, carefully sized and finished with progressive fine grades of wet and dry the new spindle runs freely and can be nipped up with finger pressure on the clamp screws. That is - once I had bored out the bad headstock bearing and turned, slit and fitted a new PB one. The old spindle nose thread was 1/2" (x20? - I've forgotten). I could obviously please myself with what to put on the new one, so went for 14x1mm. I have some Unimat tooling which will fit, there is plenty more out there and the old Toyo 3-jaw chuck that came with it just needed a new backplate to suit. Cleaned up all screws and made brass oil pots with lids and brass washers to contrast with the black and steel finishes because it just didn't look right without washers. Are we allowed to mention steampunk around here? These lathes could be bought new as a set of machined castings with rudimentary instructions on painting them yourself, so I felt justified in going for a non-factory colour. Chose black because it looked more Old School and Victorian, and because I once saw an old Britannia lathe which had been totally restored and painted black. It looked stunning.

I'd hate you all to think that everything went swimmingly with this project. I did end up remaking many pieces that I screwed up, sometimes more than once, and sometimes things seemed to take forever to sort out. But the whole exercise has been enjoyable, my skills, speed, confidence and problem-solving have all increased by an order of magnitude and I've ended up with an eminently usable bit of kit. A disproportionate number of hours have gone into it but it's turned into a labour of love at the end.

My Perris

Pete

[Jo]

Looks excellent, well worth the trouble and effort. 

Jo

[Dan Rowe]

Pete,
Yes very nice restoration work.

I took my Cowells ME apart for inspection and cleaning. The photos of your Perris show me just how little has changed on this lathe design.

I really like the new hand wheels you made. Is the zero function just a friction fit? It would be very helpful to me if you could take a photo of one of the hand wheels disassembled so I can see what you did. I like the thrust bearing idea also.

Thanks Dan

[Speedy]

Hi Dan

The handwheel and the dial are made to be a clearance fit and a groove turned in the wheel. I then take a piece of thin spring wire (from an old spring) and bend it so it forms 3/4 of an ellipse. This snaps into the groove and leaves two curves of wire standing proud of the surface. Compress these as you slide on the dial, and that provides the friction fit.



I haven't done the springs for these yet, but that should give you the idea.

Here is the handwheel off the cross-slide, complete with bearings.



The bearings are 4.5mm thick so I bored the holes for them 4mm deep to give 1/2mm clearance. Sorry no drawings. I don't really do those.

The only other thing I would point out is that the new handwheels are longer than the old ones without the zeroing dials, so I recessed the front to use the original screws. That is easily seen on some earlier pics. Anything else, just ask.

Pete

Oh. They're aluminium, by the way. Quicker and easier than making them from steel!

[Dan Rowe]

Pete,
Many thanks for the photos. Drawings are not really needed as I will make them to suit what I have in the shop.

 
Dan