Trouble with my Sabel

Hi all.
move slowly been restoring my Smart and Brown Sabel to useable condition with the intention of making a Stuart model.

I’m having lots of problems getting a good surface finish and I cannot get a few adjustments right so if anyone can offer me some guidance I’d be very grateful.

The machines cross slide was very worn, so I have replace it with a slotted Boxford one. This is better, but I cannot seem to be able to adjust the gibs and/or nut for a nice slop free feel. It’s eithe too tight, or the slide can lift. Is there any advice here?

Next, the apron. I was getting a fair bit of vertical movement when I lifted the apron from the bed. I have honed to back of the apron clamps, and the back is not good but the front still lifts. What’s the solution here?

Next (I know) the spindle bearings have shins, but if I clamp them up tight, the spindle gets tight. Is there a resource anywhere that would help me to properly service and shim the headstock, including the preload in the rear bearing which I also think is wrong.

Apologies for the long list. I’m starting to get frustrated...

Cheers, Jim

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 Andrew and thanks for the reply.
Im using Glanze inserts and holders.
Its true, I’ve not done much turning before, so it could indeed be operator error. I’m quite inknowledgable when it comes to feed rates and the like, but I’ve done a fair bit of research and tried many things.
I’ve tried various bits of aluminium, brass and mild steel, and the only things that’s really come up ok was cast iron (I turned a new backplate for a 4-jaw.
No idea of the material types as it’s all just scrap that’s lying around.

my next step was to purchase some inserts other than those that came with the holders. I’ve got some quotes from for some Kolroy ones.
Thanks for your interest in replying.
Jim

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

I haven't used any standard Glanze holders, but I do have several of their boring bars. They seem pretty good to me, but the supplied inserts were rubbish and were duly binned. I use Korloy CCMT and CCGT inserts as standard.

Brass should be fairly easy to turn. But aluminium and especially steel can be a real problem if you don't know the grade. Many low carbon steels are sticky and can be problematic when turning with inserts. I'd get known materials to experiment with, 6082 for aluminium and EN1A for steel.

If you have a bench grinder you could also try HSS tooling. It can be more forgiving of speeds and feeds than inserts.

Andrew

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 [email protected]

I hope that helps

Regards Brian

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

Cross slide wear seems to be endemic to the S&B Sabel. I would be willing to bet that if the slide was worn badly enough to have to change it then the saddle ways are going to equally as worn. You probably have a hump in the middle of the ways.

Hi all, and thanks for the great responses.
I have emailed S&B in the hope of some shims and the correct setup procedure - fingers crossed.

I will fully strip and clean the cross slide again and perhaps check for lumps and bumps in the ways and gibs. I've never used engineers blue in my life - is this the time to get my fingers dirty? Never one any scarping either - I'm scared

I really want to salvage this machine as it has sentimental value to me, but I don't want to chuck money away - it seems to have the makings of a good piece of kit, but there's a lot I don't know.

I'll report back soon - thanks again all.

This is the kind of finish I’m getting.

Oops. Double post 

Edited By Jim Beagley on 04/05/2020 21:20:42

Jim,

That looks pretty typical for what Andrew calls “noideaium grade” material [*]

MichaelG.

.

[*] Quote:

What grade is the material? Material of noideaium grade are generally not good.

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

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

Typical mild steel face cut, don't blame the machine.

Hi all and thanks for the feedback.
I have ordered some Korloy inserts to replace the cheapo ones that came with the holders.

@Brian Wood - thanks for the tips - I have emailed S&B but no response yet, I will try and adjust the headstock clamps as you suggest.

@Dave Halford - I will take a good look at the cross slide as I think thats where most of the adjustment is required. Is there a good resource to help me with possible scraping, or will I just destroy it if I give it a go myself?

@Andrew Johnson - I thought the finish was odd too, but Dave Halford thinks its OK - good old internet The finish is worse when using the apron to turn down the diameter. Maybe its just the crap steel. It seems to dig little chips out, but I thought that was from vibration.

My added problem I guess is that I dont really know what speeds and feed i'm using or should be using - again the web is a minefield. My drill has a handy chart next to the pulleys - cant I get the same for turning?

Thanks so much for all your time - its appreciated and I really hope to get better at this.
Jim

Hi all and thanks for the feedback.
I have ordered some Korloy inserts to replace the cheapo ones that came with the holders.

@Brian Wood - thanks for the tips - I have emailed S&B but no response yet, I will try and adjust the headstock clamps as you suggest.

@Dave Halford - I will take a good look at the cross slide as I think thats where most of the adjustment is required. Is there a good resource to help me with possible scraping, or will I just destroy it if I give it a go myself?

@Andrew Johnson - I thought the finish was odd too, but Dave Halford thinks its OK - good old internet The finish is worse when using the apron to turn down the diameter. Maybe its just the crap steel. It seems to dig little chips out, but I thought that was from vibration.

My added problem I guess is that I dont really know what speeds and feed i'm using or should be using - again the web is a minefield. My drill has a handy chart next to the pulleys - cant I get the same for turning?

Thanks so much for all your time - its appreciated and I really hope to get better at this.
Jim

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