First question; have you ever got a good finish when turning on any other lathe? If the answer is no, or you haven't used another lathe, I'd be looking at the tooling and material before blaming the lathe. Is the tooling HSS or insert, and if inserts what type and where from? What grade is the material? Material of noideaium grade are generally not good.

Andrew

Hi Jim

What you tend to get is an amalgamation of cross slide slide wear, gibs that get turned round and the dimples caused by the adjusters left in place, feed screw wear and finally nut wear.

You have to start with the bare slide and a cleaned up gib and see if you can push it for the whole travel by hand, it will probably jam at full out where the dovetails are hardly used and still 'new'. You have to scrape to fix this, mine showed over 5 thou on one dovetail with a straight edge and feeler gauges.

Once the slide is acceptable refit the leadscrew and do the whole cross slide test again, this will show you the leadscrew and nut backlash. Full out will be the nut backlash, in will be nut+screw backlash.

The apron front vertical lift is fixed by tightening the apron lock till it doesn't.

BTW check the tailstock centre still aligns at the chuck end vertically. As the tailstock normally has no oiler felts it may need a shim where the set over adjustment is

Hello Jim,

It might be worth your while getting in touch with Smart and Brown to see what spares they can still offer for the Sabel. I am thinking here of the headstock bearing shims.

If you are unable to source them, you could rob one bearing to make up the shortages on the other and then replace them on the now deficient bearing with a strip or two of aluminium rubbed down to get the thickness correct when the bearing is closed down onto it making a 'solid' bearing again. Drill through these to make them captive by the bearing cap screws.

The spindle is hardened and runs directly in specially grooved cast iron bearings. They look like shells but are integral with the journals

Set the bearings so that the spindle turns freely without detectable vertical lift. The thrust bearing should be set to give just a hint of end play when you pull and push a chuck mounted on the spindle, again of course consistent with free running

Smart and Brown can be contacted at:-

Bracehand Ltd, Unit 1 Stanford Bury, SHEFFORD, SG17 5NS Phone 01462 817039

email chrishallybone@gmail.com

I hope that helps

Regards Brian

Edited By Brian Wood on 04/05/2020 17:47:05

Hi Jim – I have a Sabel, with similar faults as yours, however I get good results and enjoy using it so don’t give up. I can lift the front of the apron , the only time this has caused a problem was when using a travelling steady, as the steady was lifting the saddle. I can also tighten the screws on the spindle and lock it, which suggests insufficient shim packing. I just adjust the screws to give the right clearance. I’m close to completing a sweet pea loco and all the turning and cylinder boring was done on my Sabel, which has been great. I nearly always use HSS tooling.

stephen

Interesting finish! Is the surface smooth to the touch or is it rough and the surface torn? I have seen this sort of smeary finish before. It could be the material, the insert or speeds and feeds. One thing it isn't likely to be is the lathe. At this stage I'd guess speeds (too low) and feeds combined with a sticky material. What speed and feed were used?

Andrew

Did you use any cutting fluid when machining this sample? A lot of Internet noise says don't use any with carbide but for some materials and low feeds it is better with some lubricant. I have a brush that I use when I just want a smear of cutting oil on a surface, just what is on the bristles without adding more than a few drops to the brush now and again. I also have a hand trigger bottle with "water soluble oil" mixed about 10:1 with water. Spraying this on before cutting avoids thermal shock to hot carbide.

Martin C

I'd slightly disagree with DaveH. I wouldn't be surprised to see a smeary finish on EN3, but not EN1A for instance. It's not clear how big the test piece is. But assuming 1" diameter I'd be running at 800rpm, 4 thou/rev minimum feed and 10 thou or more width/depth of cut depending upon the nose radius of the insert.

Coolant can have an effect on surface finish dependent upon material. But it really needs to be flood coolant. Dabbing or squirting on now and again is a waste of time. Unfortunately there are a lot of people on the internet who think they are a legend in their own lifetime, and a few that know what they're doing. The problem can be sorting out the wheat from the chaff.

Andrew

Sabel. Max rpm about 1200 unless you have the 600 rpm version. Facing so surface feet per minute drops to zero at the centre. Not a negative rake insert but probably not a great one if it was supplied with the holder. How fast and deep do you have to go to get blue chips coming off? Modern positive rake inserts with a microfine structure can be used more like hss.

If using a full form threading insert what rpm would you think would be needed to get blue chips off an M12 thread and how fast would the carriage be travelling?

Martin C