REBUILD: Lorch plain-turning lathe

[daxliniere]

Hey everyone!
Thanks to the kind members of this forum, my new lathe and its collets have been identified, so a new thread for the rebuild is in order. The entire process has been lots of fun, from restoring the original wooden doors to stripping and reassembling the crossslides.

First thing's first: Evapo-Rust is AMAZING. It worked wonders on the collets which had gotten kinda chunky. You can see some before and after photos here, which I think are quite shocking. I stripped down the crossslides, tailstock, and steady rest and cleaned them all with 0000 steel wool and a bit of acetone. As you can see, they came up great. The only Evapo-Rust treatment there was on the handles and scale dials, which I guess might have been chromed originally.
Still need to clean the 4-jaw chuck I got with it, but the extra faceplate that was included came up spotless.

One of the door hinge pins was missing, so naturally this was the first job for the lathe.

I'm still looking for a more modern tool post. This one works, of course, but it's pretty slow for adjusting angles, changing tools, etc.


I've got a bunch of questions and I think it's better if I add them each as a separate reply to this post, just to keep everything clean and tidy.

On another note, I just wanted to say how welcomed I've been in these forums. It's such a joy to have friendly chats with and learn from so many experienced people on here. So, thank you, again.

All the best,
Dax.

 

[daxliniere]

1) The spindle bearings have M10x1 threaded holes at the top with nothing fitted. For the couple brief uses of the lathe, I've oiled them with a little SAE30, but wanted to add the right fitting and lubricant. Should these be grease nipples and, if so, what grade grease would be best? (And how much to add?) I have some Castrol HTB high temp bearing grease in a pot, but no gun to get it in there. Would a comically-oversized syringe work?

(90 degree elbows used as dust caps in the meantime.)

 

[daxliniere]

The first step to getting this thing actually running was to fabricate a mounting system for the drive chain.

The original motor and mounting wasn't included with the lathe, but the motor-side pulley was. I fabricated a hinged bracket which mounts to the back wall of the cast iron base. I can (and needed to) adjust the camber(?) so make sure the belt wasn't running off one end of the pulley. Rubber tie-down strap gives it a little extra tension for a taught drive belt.

Question 2) The motor is a 1/4HP 1425rpm unit. I haven't stalled the machine in either of the 3 gears, but I'm not sure if this is considered sufficient power. @h-dom, do you remember the HP & RPM specs of your motor?

 

[daxliniere]

The motor pulley bearing blocks have brass bushes and little oil pots on top. I've put a bit of SAE30 in those, too, but, again, I'm looking for the right choice. One of the plastic sight glasses has a hole cracked in the top, but I was able to flip it upside down until I can find a bit of 25x25mm acrylic tube. (I considered 3D printing one with clear resin, but unsure how the cured resin might interract with the oil over time.)

Question 3) How should I approach these, specifically what type of oil to use and how will I know how if I have adjusted the amount of oil flow correctly?

Or should I just replace them with newer ball-bearing type pillow blocks for £7 each?

 

[daxliniere]

Question 4) The motor's rubber mounts are looking a bit shabby so I'd like to replace them. However, I have no idea what they're even called, let alone how to size them to select new ones. Any tips?

 

[daxliniere]

5) The Z-axis slide has beautifully-smooth motion, but the X-axis is REALLY stiff (pre- and post-cleaning). I've considered that because there is no way to lock the axes, maybe this is intentional?? It is uncomfortably stiff.
It's not because the way shim is over-tensioned; when the lead screw is removed, the dovetailed blocks slide nicely over each other, not binding at any point. Plus it's just as tight across the entire travel.

I can only imagine there must be a slight bend in the threaded shaft (which is otherwise in perfect condition) or the threaded brass socket it mates with. Both parts are definitely clean and I lubed them with lithium grease spray.
Any suggestions on how to resolve this?

 

[Agroshield]

Spindle oilers: stand with the pot of grease in your hand with your back to the lathe. Throw it as far away as you can. Leave it where it lands. For the spindle, the same drip oilers as the lower pulley shaft would do well. Check the thread pitch of any candidates you find. If new ones look out of character, consider putting the existing ones in the headstock and hiding the new ones in the cabinet. 30 weight oil will be OK for everything. 32 weight hydraulic oil is also good.

Put a tray under the oilers. If it is full after 1h, you are over-oiling it. Maybe 1 drip every 30 seconds is OK. The biggest issue with drip oilers is forgetting to switch them off when you have finished, but their volume is low so even if you do forget, it is not of an Exxon Valdez scale.

1/4 hp is a bit low, but suck it and see. If it proves to be underpowered, change it (for a three phase motor with VFD). If you change it, a slightly more flexible connection between motor and shaft will benefit you.

The motor is known as a 'resilient mounted motor'. I do not know if the rubbers are available. You can find pictures of them on Google, but mostly US suppliers or Chinese wholesalers. An old-school motor rewinder would be the best to advise you.

Take out the feed screw and put it in the chuck. Rotate by hand with a pointer in the toolpost near it. That will tell you if it is bent. I do not know how the brass nut is secured in the casting, but if that is displaced as a result of the refurb, it might bind. In principle, put the nut in its housing loosely, run the slide back and forth so the two parts find their natural position and then tighten its retaining screw.

 

[MattF]

Straightening the screw is a simple case of applying gentle pressure, somehow. You want three blocks. Rod is good, as there's minimal surface contact. Two lengths underneath, spaced out either side of the kink/bend, & the 3rd piece pressing down upon the bend. Gently apply pressure to push it just beyond the point of straight, to allow for spring back.

 

[minimutly]

Not sure if you covered it, but even with a 1/4 hp motor that belt will do you serious damage with that join - make a cover asap.
Nice simple project, it’s surprising how much you use a lathe for “manual” work, ie not thread cutting or using auto feed, so I’m sure you will be fine with this. Until the itch moves a little further out of reach of course....

 

[MattF]

Not sure if you covered it, but even with a 1/4 hp motor that belt will do you serious damage with that join - make a cover asap.

If the link snaps, the belt will stop moving very quickly. It isn't going to become a flail.

 

[minimutly]

If the link snaps, the belt will stop moving very quickly. It isn't going to become a flail.

You missed my point - or did I not really make it well - those joints are famous for catching in sleeves etc...

 

[h-dom]

@daxliniere

I had a 1.5hp 2800rpm motor on mine but there were various pulleys so I'm not sure what the final speed ratio was. I generally had it set on the middle speed and it did everything I needed it to.

It actually came with a 0.5hp motor with clutch. I couldn't get on with it, kept slipping and the motor burnt out very quickly so I replaced it with one I had lying around. I definitely didn't need 1.5hp but it was fine. 0.75 would probably be ideal.

The spindle bearings, mine had drip oilers as said above. They were clogged up with grease though when I got it so I cleared them out and occasionally dropped a bit of any oil I had nearby.

I'm hoping your lathe will be a bit more rigid than mine. I think the gap that was cut in probably lost some rigidity and the fact it was on a wooden bench rather than the cast one you have. I cut all sorts on it from brass up to en24 and stainless alloys so yours should be great for small to medium size work.

 

[James1979]

I was wondering about leaving mine in the middle setting then using a vfd to control the speed for my S&B which is similar.

 

[daxliniere]

Spindle oilers: stand with the pot of grease in your hand with your back to the lathe. Throw it as far away as you can. Leave it where it lands. For the spindle, the same drip oilers as the lower pulley shaft would do well. Check the thread pitch of any candidates you find. If new ones look out of character, consider putting the existing ones in the headstock and hiding the new ones in the cabinet. 30 weight oil will be OK for everything. 32 weight hydraulic oil is also good.

I LOLd when I read that and the Exxon Valdez part. (LdOL?)
A pair of the same oil pots can be had on AliExpress for £6.50 delivered, but my main thought is space. I'm going to make a cover that goes over the drive belt, front to back, with a hinged lid for access. If I use the original style of oiler, it's going to require the cover to be quite tall. I also worry about kocking and snapping them off accidentally..
It would be great to find a low-profile alternative, or perhaps pipe them in from a larger pot on the wall.

I'm wondering if it makes more sense to just switch the motor shaft's brass-sleeved bearings for ball bearing pillow blocks with grease nipples.

Maybe 1 drip every 30 seconds is OK.

Ok, that is excellent to know. Thanks. That goes for both spindle and motor shaft bearings?

1/4 hp is a bit low, but suck it and see. If it proves to be underpowered, change it (for a three phase motor with VFD). If you change it, a slightly more flexible connection between motor and shaft will benefit you.

Alright, cool. Thanks

The motor is known as a 'resilient mounted motor'. I do not know if the rubbers are available. You can find pictures of them on Google, but mostly US suppliers or Chinese wholesalers. An old-school motor rewinder would be the best to advise you.

Great. I've found Remco as a supplier of such motors and emailed them about it. Hopefully I get a response soon. Perhaps it'll make the whole thing a little more smooth.

Take out the feed screw and put it in the chuck. Rotate by hand with a pointer in the toolpost near it. That will tell you if it is bent. I do not know how the brass nut is secured in the casting, but if that is displaced as a result of the refurb, it might bind. In principle, put the nut in its housing loosely, run the slide back and forth so the two parts find their natural position and then tighten its retaining screw.

Ok cool, I'll do that with the lead screw.

The brass 'nut' is actually a stadium-shaped piece of brass about 15mm tall that slots ever-so-neatly into a perfectly matching 'socket' in the slide, with a thread tapped through its length. There aren't any screws needed to hold it in, I guess you'd call it a transition fit.

 

[daxliniere]

Rod is good

I've never met Rod, but I'll give him a shout.

Ok cool. I guess I can make a jig for my pedestal drill. That should have enough controllable pressure to do the job. Thanks.

 

[daxliniere]

You missed my point - or did I not really make it well - those joints are famous for catching in sleeves etc...

Thanks @minimutly. I do intend to build a cover that replicates the original, as shown in this photo from @gaz1, but adds a hinge to cover the top and back. This way I can use it as a little shelf while working.

 

[daxliniere]

...oil pots...
It would be great to find a low-profile alternative, or perhaps pipe them in from a larger pot on the wall.

Hmm! I could probably add a solenoid valve that would open the oil reservoir only when the machine was powered up!

 

[gaz1]

you would be far better off using 5mm angle iron with lugs on the sides to slot into the lathe bed

one for the front one for the rear

then you want an over the top piece to sit on both

this way will allow you to sink screws into the 5mm angle iron and also screw them up

top piece is removable

you dont want to be storing on top of it you wont like vibrating pieces or even the lathe chuck key being virbrated and then caught and fired across the room

 

[daxliniere]

Fair enough. I'll see how I get on with it. Maybe it'll need borders and a rubber mat.

 

[daxliniere]

Take out the feed screw and put it in the chuck. Rotate by hand with a pointer in the toolpost near it. That will tell you if it is bent. I do not know how the brass nut is secured in the casting, but if that is displaced as a result of the refurb, it might bind. In principle, put the nut in its housing loosely, run the slide back and forth so the two parts find their natural position and then tighten its retaining screw.

I went to do this, but ran into a problem: How do you indicate on a threaded rod?