Hello from Oxford - Problems with a SABEL lathe

Hello Stephen,

I too was curious about the bronze coloured bit, neither my spare spindle nor that fitted to the working lathe have it.

The spring loaded oiling felts are an added complication in fitting spindles, try as I might I couldn't find a side opening of any sort like that adopted by Myford for the front bearing on the ML7 to be able to pin them down and release them once the spindle was fully home.

Brian

The bearing cap threads arent that smooth to be honest, especially the small end. Maybe its the bolts themselves, Ill investigate further, but there is some varying resistance when torquing them down.

I did have issues with the chucks wanting to undo themselves and such when I first got the lathe and not wanting to screw on tight. But after cleaning the bores of the chucks and spindle threads they seem to sit fine and no longer want to undo themselves. Should I try removing that bronze bit? I thought it was screwed on the spindle, but its not, spins round its own axis with a bit of resistance. Im not a big fan of the chucks that came with the lathe. Both the 3 and the 4 jaw had surface rust. They were hard to tighten and I thought it was corrosion stopping them. Marked the 4 Jaw chuck and the backplate, to make sure I put it together as they sat before, broke it down to pieces, cleaned it out, but some of the jaws still have quite a bit of resistance when tightening/loosening them. This resistance seems like the jaw screws are rubbing on something but I couldnt really tell what when I had it apart. The seller said there were replacement jaws included, but as I later found out they are too big to fit..

As for holding down wicks, theres 2 small holes on each of the bearing faces, I just pushed down the wicks, stuck some thin stainless tig rod when fitting the spindle and it held them down fine. I tested it couple of times to make sure the wicks pop out when I remove the filler rod prior to fitting the spindle

I could upload the Southbend 9A rebuild manual that I got when I purchased the rebuild kit, about 40-60 pages as far as I remember. It's got parts list, detailed drawings, procedures, etc. Almost everything applies to this Smart and Brown lathe. If theres any interest?

I also discovered another issue - quick change gearbox. In very low feed speeds, both slides furthest to the right, everything seems fine and the leadscrew turns easily, but as soon as you increase the feed rate, theres this spot where it sort of binds. Like 3/4 of a turn go so-so and then you get into this binding and it wont turn anymore unless you reverse the direction. All this testing was done by hand, didnt send any power from the spindle as I didnt want to break any gears. But Ill leave this for later, just wanted to mention it, maybe someone had same issue and figured out what it was.

All that comes to my mind at the moment is "Why me problem" https://youtu.be/uqemucA0jLI?t=2m28s

Hello K,

Thank you for the explanations, but I didn't have the bronze coloured bit you mention, I have little idea what it is supposed to do. And thank you too for the information on holding down the wicks, I'll have to look again. My lathe has been painted in thick silvery anti-vandal elevator paint and I wonder if the openings have been blocked by the paint, I really couldn't believe that sort of detail wasn't present. I take it the access to these magic holes is from the outside of the headstock.

On receipt I took my gearbox to pieces to clean it and understand it's workings, mine is free running now over all the ratios. Having an open bottom it was very grubby in there, the lathe had been installed in a woodworking shop in a past existence and while I couldn't identify the make up of the crap that came out, it is quite likely to have been largely wood dust.

The motor was full of it; the previous owner had fitted a 1/2 hp motor with VFD that I have moved onto my Dore Westbury mill where I think it will be more useful. Therefore I refitted the old Crompton motor having dug out all this junk where I could---I had been told about it and was advised to test it electrically before use which thankfully checked out just fine. I still think the lathe is under powered and have a 3/4 HP motor ready to fit when the weather is more encouraging to work out there. My Myford ML7-R is about 3/4 HP and it is a smaller lathe, I have no trouble taking man sized cuts with that, you can hear it settle down to work without struggling on some of those.

As a side issue I have been plagued by belt slip, even when it was set near bar tight and finally spotted the problem. The aluminium 4 step cluster pulley on the countershaft had badly worn belt grooves of J section, the belt was actually running on the bottom. The 2 stage aluminium motor pulley was equally badly worn and the transmission as a whole was so I bad I was able to hold the chuck by hand with the motor running! I blame the wood dust for that wear.

All sorted now, I re-machined the grooves in the motor pulley and replaced the 4 step with the spare cast iron 4 step that fits the spindle, having cut off the integral gear on the end of it and sleeved the bore to suit the countershaft. This wasn't the act of vandalism it sounds like; the previous owner inherited the lathe with a broken tooth on that pulley cluster. found of course that the gear is not a spare part and in the end he bought a second lathe to rob that component from. All that was left of the carcase when I bought the lathe as a second machine from him was the headstock pretty much complete, a change wheel door and some other odds and ends. He covered his costs in the sale of bed, leadscrew, tailstock, gearbox and carriage parts

Enough for now

Regards

Brian

I also haven't been able to find the holes in the headstock for pinning down the wicks on my SABEL, although they are definitely shown on the smart & brown drawings. I wonder if they are plugged and painted over?

I do have the original test certificate, dated 3rd Feb 1953, with the names of who tested, checked and passed the lathe.

Hello Stephen,

I think I have found them, they must be the small holes at the bottom of the wedge shaped outer annular steps machined into the bearing housings which I thought were intended to work much like labyrinth seals and drain oil back into the well below the bearings.

Pulling pins out of those while manipulating the spindle, pulley cluster, thrust bearing and vee belt into position and avoiding disturbing the spindle during pin extraction requires careful choreography of a cast of thousands to do it all, not forgetting the dolly bird to mop sweaty brows and murmur nice things to mitigate the language.

Perhaps K has found out how all that is done on his own without losing your temper. I look forward to seeing what he says.

Regards

Brian

Hello K and Stephen,

I didn't say pins were a standard feature, just that those holes must have been the ones you used to hold down the felts against their springs when you re-assembled the spindle. The pictures are a bit hard to interpret to offer definitive opinions on, blue seems to be present over the whole surface of the bearings and with slack bolts I don't think that is a bad state of affairs.

Did you try lifting the spindle and moving it sideways to feel for any detectable slop, that would be a rather more definitive test in my opinion.

Out of interest I checked my spare spindle in the spare headstock today with just an oil film on the spindle, there was no detectable slack on either bearing with slack bolts and maybe a very slight degree of added drag with the bearing cap bolts pulled down hard on the shim stacks--it still rotated easily. Those threads by the way are 3/8 inch WHIT16 tpi.

UNC bolts are also 16 tpi but they will have the sharper 60 degree thread pitch which will not give the best fit in the headstock since the mismatch in thread angles will only allow partial contact to be made in the thread walls and the thread tips are finished differently. The UNC bolts may even be contacting the bottom of the WHIT form tappings. Try the situation with known cap bolts instead to see how things behave then; I think you will get a much more gradual degree of adjustment as a result.

The headstock fitted on my working lathe has oil cups on the top of the bearings, as well as the sprung felts and the little push fit plugs to the top up holes alongside the oil wells. One other difference is the inclusion of a grub screw in the upper side of the bearing cap to get a grip on the bearing adjustment bolts and lock them at a chosen setting. I didn't like the way they were compressing the thread on the cap bolts at those points and machined them away to allow the grub screw to grip on a plain diameter of the bolt instead

Finally, the strange bronze collar thing will definitely prevent the chuck and spindle registers from meeting as they should to properly align the chuck in its fully seated position; at the moment it is only located by the 8 tpi spindle thread and will be inaccurate to a variable degree as a result, You can't expect the lathe to do anything accurate like that so take it off, it is doing you no favours.

Regards

Brian

Hey all,

Long time reader, first time poster.
Also have a Sabel picked up recently (Also around Oxford too)
Regarding the headstock bearing lubrication, i find that if i squirt a bit of oil into the holes under the caps, generally the level always drops to the same level in a few seconds, and leaks out of the overflow and down the front below the spindle. Was wondering if others see this behaviour, or if I may be missing a felt wick or something. The oil I've been using is pretty thin stuff supposedly for plain spindle bearings on machine tools, so hopefully not far off correct.

Thanks

Don