Lathe restoration SN20

[Frank S]

Serious stuff, the TOS machines I've seen have been virtually bombproof. One interesting thing I saw on one about ten years ago was that both longitudinal and cross feed could be set at different feeds and both engaged alone or together. I've never seen or heard of anything like this before or after. Owner said it used to be used in making tank parts. I don't know whether this was a special or an option but I thought it was a great idea.

I used to own a gromematic Dutch built lathe that could run both the cross and the longitudinal feeds Simultaneously by engaging both the lead screw and the feed shaft but not independently adjustable.

[NortonDommi]

That's very interesting. As said I'd never even heard of anything like this before, I suppose it could have been set up for turning standard tapers much quicker than a taper attachment. Was a pretty sizeable machine though, wouldn't have fitted in my shed : P From memory it could also cut just about every thread in existence and I suspect you needed a special license to operate.

[thehomeengineer]

Hi
I had a TOS lathe wish I never sold it but needed the money as I was buying a house. The clutch went on the lathe and in the UK the 600 Group offer spares for TOS lathes.600 Group PLC - manufacturer and distributor of machine tools, laser marking systems, precision engineered components and mechanical handling & waste management equipment The spares were expensive so had the bits need for the clutch lazer cut.

[TexBuxer]

Here are the pics, it's easier to use postimage.org

[TexBuxer]

How can I remove slide?

I have removed tapered lock piece.



Allen bolt was removed, but I couldn't remove the slide.


Start lever is broken, all shafts go through feeding box.


If i could remove shafts rear bearing, I maybe could pull feeder mechanism out from back end.

[Frank S]

I for one am not in favor of grinding the bedways let alone trying to build some portable grinding device capable of maintaining all of the many flat angled and vertical surfaces in true precision parallelism and angularity. Before such a method is even considered other options should be investigated.
In all cases you will need a couple pairs of matched V blocks, 123 blocks long precision machinist straight edges and shorted ones , a set of parallels dial indicators depth gacues and other precision measuring equipment like a precision machinist protractor machinist squares verniers or digital calipers all of these are required to determine which surfaces are the ones worn most of all a good pencil and note pad and some marking agent such as dykem (Prussian blue).
You may find that using such devices as block sanding/ or scraping planes or a large machinist file, hand scrapers and or power scrapers will be the better choice for truing your ways. You may also find that just a good cleaning and oiling then adjusting the carriage will be good enough even if there is some slight deviation in tightness throught eh length of the travel you will need to check the concentric alignment of the spindle to the tail stock and run out.
But to try and DIY some form of grinder to do this for a 1 off would be quite an undertaking in itself. Even if the bedways were ground to shape the likehood that they will require scraping afterwards is high on the scale
That's just my opinion

[Toolmaker51]

Pics are a little small...but slide won't move off carriage until nut from cross screw is detached. To withdraw screw, the bearing supporting handle end also has to be freed from housing, it might go to backside, rare on engine lathes. With 'tapered lock piece' [the gib] some side to side clearance should be present. Unless everything is disconnected it'll shake but nothing else.

[Frank S]

Pics are a little small...but slide won't move off carriage until nut from cross screw is detached. To withdraw screw, the bearing supporting handle end also has to be freed from housing, it might go to backside, rare on engine lathes. With 'tapered lock piece' [the gib] some side to side clearance should be present. Unless everything is disconnected it'll shake but nothing else.

by clicking on his pictures a couple of times the grow very well.

[TexBuxer]

I got the shaft bearing separated.


bedways are rather worn. I don't know if this restoration is any good.


Is this somekind of thread freeplay adjustment, how should I adjust it?


What material scraper is, how to replace

[Toolmaker51]

What material scraper is, how to replace

First off this machine hasn't issues of many, many I've run across.
So #1. it's not Chineseium.
#2. it probably doesn't have plastic gears.
#3. It does have separate feed and threading shafts.
#4. The chip pan is sure to catch coolant. I had to run [gag] a Chineseium while back and the gutters not only leaked, didn't even project beyond certain edges to stop plain drips. I'm not elitist or machine snob, but who hasn't watched rain on surfaces???
I will point out avatar to left. It's ~60 years old, 9800 pounds and I've swung 20" missile rings. My second capital purchase, I probably investigated 100 lathes with capabilities desired; sifting about a dozen when this came to auction. Shot to A list immediately.

Your SN20 carriage bridges a pair of ways; front and back and across side to side, a great surface area increase. The gap shown by your straight edge may or may not have significance. It'll be common up adjacent to headstock; if that gap is at far right side that's serious wear. I'll bet that's not the case. And definitely not beyond repair. At this instant though, it's not within scope of a couple forum posts.

Scrapers have been made in a variety of material. These can be made of solid brass, felt, shim stock, oilproof rubber, engineered plastics...or a combination. The best scrapers are composite, ie felt oilers and metal covers to protect felt and displace build up of chips. Whole idea is eliminating their access into sliding surface. 100% is nice, but hard to achieve.