Thread: Hercus AR saddle re-assembly

I've broken the rules. When I pulled my saddle to pieces for restoration, I didn't take notes.

I figured I'd have it stripped down, painted and re-assembled inside a week. Well, one week has turned into months, and I'm left scratching my head with a suitcase full of parts and no sketches. Sound familiar?

The first problem I have is the gasket that goes behind the oil retaining plate. It's in 3 pieces. It's about .38mm thick, and is made of a fairly stiff material. Where do I source a small piece of gasket material? Could I use use cardboard, say off a Cornflakes packet?

With respect to re-assembly, I'm not entirely in the dark, I did manage to find an exploded view of the apron on a Southbend site, and can only hope it is similar to the Hercus model.

If I get stuck, is there a kind member who is willing to drop in for a coffee and guide me through the re-assembly process? I'm in Heidelberg.

Mechanical things don't normally lick me, but this one just might. I can't believe all these parts came out of one apron.

Ken

Ken unless you can go to an Enginerering company and purchase a small piece pf Gasket material from them the Cardboard would probably get you out of trouble,although it will be porus and allow oil to seep through,it should be ok.

You could make a more permanent type by using Milk bottle its about .020".

I dont think the extra .004"/.005" would make much difference to the position of the Tin plate cover.
You could also try Gasket Eliminater but the Cost may be prohibitive.

If you use the Carboard it would be better if you also apply some type of Gasket Cement either hard or non hard setting.

i think u could in a emergency and ive used lots of different materials like chart paper but that was because i had no other options. is it part no 53 your worried about. locktight has some liquid gasket.
i think its 510 that works well.

Time for a well earned glass of "medicine". Finally got the apron re-assembled, without any bits left over. Had a lot of trouble reinstalling the two half moon washers in the clutch. The two washers are not sitting flat in the clutch housing, and it seems, this is the only way they fit.

Just have to sort out a gasket, and wallah, another section of the "old girl" finished.

Thanks for your comments re gasket paper. Might try a carburetor specialist, they may have some suitable material.

Pics are coming when I can find the camera.

Ken

Try also any car accessory shop for gasket material. Watch the screw heads that hold the plate on don't foul the leadscrew. The 2 upper ones are countersunk on mine.

Jordan

nadroj,

thanks for the tip re screws, will make sure I get it right.

Ken

I managed to get hold of some gasket paper. Only needed a piece 100mm x 50mm, had to buy a 1m roll x 300mm, still for $10, I was happy. At least now I will have enough for another 200 lathes.

The paper is 0.4mm thick, and was easy to cut.

The close up of the clutch shows the two half moon washers, cocked up where they wrap around the shaft. I guess this is how they are meant to be, as they don't fit in lying flat. I reckon tightening the knob on the other side pulls the shaft in and causes the half moon washers to expand out and push the clutch jaws out against the clutch housing.

Am I correct?

I've attached a few pics for us Hercus heads.

Ken

> Am I correct?

Yes, that it how it works. With the star wheel you set the clutch force, just enough to get the feed going uniformly for your cut - I add a little to make sure the cluch won't slip during the cut. It is a protection mechanism in case of a collision. For example when facing outwards from the center, the cross slide easily hits the end stop, that would break gears (or at least shear pins) if there was no clutch. It is a great feature of South Bend lathes, not all newer lathe designs have such a luxurious clutch!

Check the worm has no play left-right. If it has, you may want to make a new retaining ring. If a lathe is used a lot with automatic feed, you get this side play
as the apron bearing bracket wears.

Chris

Hi Chris,

Thanks for the clutch mechanism explanation. I haven't got my Hercus up and running yet, and to be honest, don't really know how everything works yet. There's no discernible end float in the worm. What would be the outcome if there was?

Won't be long before I start cutting metal, just have the bed, guards and cabinet to restore.

Ken

No felts visible in the photos, or mentioned in the text. Have you reinstalled them?
Anyone who hasn't dismantled a saddle yet - if you want to remove the slotted screw for the clutch knob, be aware it's a left-hand thread and easily broken if forced the wrong way.

Jordan

Jordan

There are no felts that I'm aware of in the apron. There is however a woven cord that lubricates the star wheel. It's just visible in the enlarged view of the clutch assembly. A recess in the casting is where it is located.

Ken

So there is Ken - I was looking at the other pic where it isn't obvious.
There is at least one more felt wick, in a slot in the housing for the worm. It gets oil from the other end of the wick you mentioned. If you haven't removed the worm gear, you wouldn't have seen it and it's probably OK.
The USA book, "A Guide to Renovating the 9" South Bend Precision Lathe" has good info on this.
After seeing the clogged up mess that was my Hercus 9" clutch bath, I'd recommend all to check their saddles. Mine didn't seem to accept oil from its filler plug - reason was obvious when I found decades of compacted swarf buildup. It all came good after a clean out though.

Jordan

> There's no discernible end float in the worm. What would be the outcome if there
> was?

If it was very bad, it could cause a slightly irregular (jerky) motion of the saddle under automatic feed, which would be visible on turned surface finish as a repetitive pattern. It can also cause problems when drilling from the toolpost under automatic feed (pulling the drill into the workpiece) and when doing interrupted cuts under automatic feed. Some people like to couple the tailstock to the saddle for automatic feed when drilling (the saddle dragging the whole tailstock behind it) and with too much play in the automatic feed this setup can do funny things.

As for the wick, I sacrificed a good old full cotton shoestring (the thick type for better hiking shoes). This wick is difficult to install, it has to go up a narrow angled bore from the bottom of the oil pit to the worm shaft, needs to pushed through with a wire. By the way, the same shoestring also fits for the short wicks inside the tumbler reverse gears.

Did you remember to re-install the interlock pin between the half-nut handlever and the automatic feed selector lever? With this missing, it would be possible to accidentally engage both half-nuts and automatic feed, which would cause the apron to spit out a tooth or two.

Chris

Originally Posted by cba_melbourne

> This wick is difficult to install, it has to go up a narrow angled bore from the bottom of the oil pit to the worm shaft, needs to pushed through with a wire.

It can also be pulled up, with wire attached and inserted in the hole first. The worm gear needs to be removed for this method.

Jordan

Originally Posted by nadroj

It can also be pulled up, with wire attached and inserted in the hole first. The worm gear needs to be removed for this method.

Jordan

Why did I not think of this? My brain was fixed at pushing it up that hole.... pulling would have been much easier, even with a simple sewing thread, that could even be chopped off and left in place. Chris