Small metal lathe

[WoodchipWilbur]

Thanks for the description of your process.

To me, it seems that working on the outside first would be easiest. You just need a concentric, conical stub on the lathe mandrel. Push/drive/wedge the open end of the bell onto that, tap it concentric with a mallet, drill a centre hole from the tailstock and then use a tailstock centre in the argent to keep everything in place while you work on the outside. Then the shape and concentricity of the argent itself is immaterial.

Once the outside is finished, use it to cast a female mould (plaster of paris in a metal tube) that can be attached to the lathe mandrel. Drill and tap a hole in the argent for a drawbar through the headstock (do this as the very last step of outside machining). The drawbar will retain the bell and the exterior mould will support it while you work on the inside.

Brass is good because you can cut it with zero rake tooling. That means a form tool for the inside is a possibility.

Please see from 1:00 to 2:00 of this video for an alternative method of manufacture

What a wonderful film! Cut glass accent and a splendid mid-century adherence to the good old Elf and Safety. I think my favourite is the foundry workers gear - cloth cap and a positive attitude...

To business...The conical stub is actually the route I take for machining the outside. Sadly, any sort of meaningful hole drilled through the argent is not possible for a traditional handbell. Certainly not enough to fix a drawbar. I'll not witter on as to why. For the kid's bells, I am fairly convinced that the cylindrical argent is the solution. That can then be ground down to the traditional argent which is then used to attach the looped leather handle as well as the drilled and tapped fixing for the clapper system. Because these bells don't make a p[art of a "set", they can all be the same size and so I can do much more repetitive production.

I like your idea of a cast female mould. For the kids' bells, I actually do the inside first simply because it is easier to grip the rough-cast outside in my (woodworking) jaws, but for these, accuracy is less important. My jaws won't close down enough to grip the round argent so I haven't been able to try that. I am toying with the idea of a turned wood female socket - especially for the bell metal castings where it would indeed be best o get the outside up to spec - and then tune it from inside. A downer is that, to sound the bell for tuning, it needs to come off the lathe, with all the re-centering problems that this creates.

I think I've got a whole shed load of things to learn about form tools. I'll go, ask My Friend Google...

 

[Fergie 307]

OK - responding to several bits here...
As Fergie 307 says, something like the Drummond (or anything on its own stand) is a no-no. My workshop (mainly a woodwork shop) is 3.8m x 2.7m (sorry - smaller than the 15 sqm I mentioned above). One side has work surface the full length with space below for things like table saw, p/t, router table, scroll saw, extractor (all on castors to move out when required). Full width windows this side and power sockets above.
Across the back is my lathe (off its legs and mounted on a storage cupboard.
Down the other side is a long "chest of drawers". These are all modular, 60cm swuare and hold a big variety of stuff. Full width doors at the other end.
Any lathe will have to go on the long chest of drawers. (Which otherwise has a tendency to collect junk!)
"I can't imagine turning bells requires enormous accuracy" Well... yes and no! The main part of this job (answering Owd Jockey) is to clean up bells cast by my Junior School "MiniRingers Club" each year. This club runs through the school year - and it culminates in the casting of bells. (Gosh! Surprise! - they don't get to pour hot metal - but they do prtty well eveything else.) The patterns I am using are genuine handbell patterns (we think, Warner's c. 1900) - and they are far too thick. This makes the casting easier but, till a fair bit of metal is removed, they won't "ring".
All of that requires relatively little accuracy - EXCEPT that, if the walls of the bell are not uniform, then the note of the bell "wows" unpleasantly. We try to avoid that. These bells are all cast in brass because it is both easier to pour than the proper bronze (a high tin content alloy - 30% tin) but it is also far more readily available - and cheaper! I have bell metal and use it for my own purposes. It is't half gloopy to pour though!
This is where the accuracy comes in. If I am making a proper tuned handbell, I am trying to tune it so that it vibrates to within a couple of Hz of the right notes. A handbell is tuned with three significant notes (the Dominant, the Hum (an 8ve lower) that the Tierce (a 3rd higher), all tuned at different points of the bell. I wouldn't dream of doing this final tuning with any cutter - 400 grit wet and dry is my toy for that. What I need to do is (in a relatively rough and ready way if necessary) to reduce the wall tickness from around 4mm to around 2mm.
The MiniRingers have a set of commercial handbells - 2 chromatic octaves (25 bells) that are insured for £10,000 - they are not exactly rough-cast and cheap!
The idea of brazing (I don't braze!) or casting a suitable argent (the proper name for the "tang") is very much part of my scheme. The set of patterns I have includes some with exactly what is required: an accurate concentric cylindrical argent. Part of my task for this year (we have just finished this year's casting) is to create a new set of patterns (they are made of aluminium), all of which have this cylindrical argent which will (I hope!) make cleaning them up a great deal easier.
I think Andy's mini-lathe is probably too small.
And, Richard_C, yes, I have tried, but with little success. I think that part of the problem is that, to do anything inside the bell, I need too long a reach - and it starts bumping around alarmingly! I made up a set of "wood turning" tools with carbide tips. From what I've been reading, I suspect I may have done better with HSS. I'll have another bit of a trawl.
Thanks, everybody!

Very interesting stuff. And apologies, when I said I don't suppose it requires great accuracy, I certainly wasn't being at all derogative. One of the main criticisms of the small Chinese lathes is that they are often not dependably, and repeatable accurate to the sort of tolerances you really want from a metal lathe, sub 0.01 mm. I was simply suggesting that for forming your bells that degree of accuracy is probably overkill, in which case that type of machine may be perfect for your needs, and space available. Doing it commercially in the old days, before CNC, they would probably have used a hydraulic copier attachment to a decent sized lathe. In this case you install a pattern piece in the copier, which is then exactly duplicated by the lathe. I turn a lot of brass, and yes HSS tools are best, and used with Power feed where possible.

 

[Fergie 307]

As for finishing the argent, have you thought of just casting it longer than necessary. In that way you can mount it in the chuck with the section that needs to be machined exposed. You can machine the whole thing, including the argent without removing it from the lathe, then just part off the finished bell. Ordinarily the disadvantage of this approach would be that you are going to have a sizeable chunk of brass left in the chuck, so rather wasteful of material. In your case however this could just be recycled to make more bells! Saves all the hassle of trying to find a way of mounting the finished bell in order to machine the argent, just a thought. And one carbide tool you might find useful is the type with a circular replaceable tip. Won't give quite as good a finish as HSS, but very useful for machining anything with curves. Abranet or similar is worth looking at as an alternative to wet and dry for finishing, doesn't clog the way wet and dry tends to, especially with soft metals like brass. Hope you will update is as to how you get on, sounds like fun.

 

[WoodchipWilbur]

As for finishing the argent, have you thought of just casting it longer than necessary. In that way you can mount it in the chuck with the section that needs to be machined exposed. You can machine the whole thing, including the argent without removing it from the lathe, then just part off the finished bell. Ordinarily the disadvantage of this approach would be that you are going to have a sizeable chunk of brass left in the chuck, so rather wasteful of material. In your case however this could just be recycled to make more bells! Saves all the hassle of trying to find a way of mounting the finished bell in order to machine the argent, just a thought. And one carbide tool you might find useful is the type with a circular replaceable tip. Won't give quite as good a finish as HSS, but very useful for machining anything with curves. Abranet or similar is worth looking at as an alternative to wet and dry for finishing, doesn't clog the way wet and dry tends to, especially with soft metals like brass. Hope you will update is as to how you get on, sounds like fun.

First:
Thanks for the quite unnecessary aplology! I didn't feel derogated (a real word?) In the case of the kid's bells, you are spot on. After a casting session, we have 12 bells - all of which need to be fettled up, ready for the next week. Speed and "pretty" are far more important than any accuracy. I'm a 75 year-old geriatric. Not only do I work a good deal slower than I once did but also, now I am retired, I have so little time available. (Don't retire, folks. NO Days Off. NO Holidays. NO Sickies. It's 27/7 hard grind!)

Second:
My Brain Cell was just getting round to the longer argent. Initially, this was a problem because a longer argent means building taller casting flasks. That means more casting sand (it currently takes about 100kg of sand to service a group of 12 kids) and that increases the cost as well as storage and transport problems.
However, I have to create a sprue down which to pour the metal. Normally, this is pressed through the sand beside the bell and a channel dug so that the metal flows across and into the bottom of the casting then up to the top. It is equally possible to pour directly down through where the argent will be. The quality of the casting is often poorer but the total failure rate for a passable casting is reduced. Ergo, I can increase the argent length and call it "sprue". Well worth a try.
I will have to see how well the pattern releases from the sand. It will absolutely certainly need to have a slight taper on it. I think about a 1 degree draft angle is called for so I don't imagine that this would have a huge effect.

I was lying awake last night, thinking of better ways to machine the wedge-shaped argent from the cylinder. (Again, for a good night's sleep, don't get old.) I have no milling machine* and I am wondering about a suitable jig for my router table. Having lost the tip of my finger to an inappropriately-used router, I am, you'll guess, going very carefully on this.

I was thinking of creating a curved bit for the bell out of HSS. I have my little furnace, so another little learning curve is going to involve the annealing process. Not started that yet. A circular carbide tip sounds good. How far from the toolpost can I reasonably extend the cutting surface? Presumably, if I go too long, I'll get unacceptable chatter. With the bells I am doing at the moment, I'm looking at 60-70mm but I could well (ie will) want to go bigger. Unlike a wood late, you can't poke the tool rest into the hole.

And, yes. Abranet (or a cheaper clone) is good!

*Before you make recommendations; I have no space and the Chancellor Indoors won't approve.

 

[Fergie 307]

You can buy boring bars with the circular tips which should reach far enough. As to how to machine the wedge, could you cheat a little and use a grinding wheel to get the basic shape, then finish it with a file? You could turn it to the shallow cone in the lathe so all you have to do is flatten the sides. A decent size belt sander would do it if you have one, or even an angle grinder, with some care!

 

[XTiffy]

In my Royal Navy apprenticeship, once all exams were finished I was detailed off to the workshop to make mini brass cannons (think HMS Victory). These were given to visiting VIPs. I found that you could quickly turn them free hand, using the X and Y cross slide handles, with an aluminium profile gauge to check on shape etc. Much as you do on a wood turning lathe. Making the timber carriage was another learning curve. Some wood turning lathes did have an accessory cross slide available (Myford ML8 ?).

 

[WoodchipWilbur]

Now... the timber carriage would be grist to my mill!!

Small lathe update:
The two that Sachakins pointed to finally went for around £230 and £250. I bid - but I felt that this was far too much to pay for an unknown kit of parts when a new one is only about £100 more.
I did see a fully working one with a huge looking box of tools, cutters, chucks etc etc for £350 (on FB Marketplace). Didn't go for it - it was in Portsmouth and well out of my motoring range!
I have, however, seen another one (standard Chinese 7 x ?12?14 CJ0618) close by (40 miles) at £60.
The snag? "It doesn't work - don't know why"
Now, at £60, I don't think I'm likely to go far wrong. The lathe "has never been used" though the paintwork doesn't look pristine. The seller has good ratings - and is clearly quite busy on FB market. A new motor or controller aren't wickedly expensive.
At the moment, I'm waiting for my offer to be accepted. Let's hope that all goes swimmingly!

... and, Fergie 307; I have NO intention or buying any boring bars. All of mine will be exciting! Sorry. Old joke. But, to be serious - comments like yours are so useful. That tells me what to look for - a boring bar (though some of the Amazon prices look scary).

 

[Sachakins]

I got similar to this for my wood lathe.
https://www.ebay.co.uk/itm/18593922..._TECSIwRW6&var=&widget_ver=artemis&media=COPY
Needed accuracy for doing ring's etc.
I've got a swivel head on my lathe, s easy to set piece at angle to do internal tapers.

Don't know if it would help.
You can get similar but for use on a cross slide on metal lathe I imagine.

 

[dangles]

Now... the timber carriage would be grist to my mill!!

Small lathe update:
The two that Sachakins pointed to finally went for around £230 and £250. I bid - but I felt that this was far too much to pay for an unknown kit of parts when a new one is only about £100 more.
I did see a fully working one with a huge looking box of tools, cutters, chucks etc etc for £350 (on FB Marketplace). Didn't go for it - it was in Portsmouth and well out of my motoring range!
I have, however, seen another one (standard Chinese 7 x ?12?14 CJ0618) close by (40 miles) at £60.
The snag? "It doesn't work - don't know why"
Now, at £60, I don't think I'm likely to go far wrong. The lathe "has never been used" though the paintwork doesn't look pristine. The seller has good ratings - and is clearly quite busy on FB market. A new motor or controller aren't wickedly expensive.
At the moment, I'm waiting for my offer to be accepted. Let's hope that all goes swimmingly!

... and, Fergie 307; I have NO intention or buying any boring bars. All of mine will be exciting! Sorry. Old joke. But, to be serious - comments like yours are so useful. That tells me what to look for - a boring bar (though some of the Amazon prices look scary).

Hello.
I have a working mini lathe with quick change tool post and a few
tool holders,follower guide and a milling attachment made for
Chester lathes(by the Chinese of course),£300 but it would have to
be collection as it's too heavy to post.
If you are interested I can send you some pictures.

 

[WoodchipWilbur]

Yes! Well interested. Got gazumped on the £60 quid one
Send some piccies and I think we can do business. I think you are Leicestershire. It's possible I could swing by on Sunday.

 

[dangles]

You will have to stand on your head to view some
of the pictures(my daughter took them).

 

[Sachakins]

Do you use carbide or hss?
If carbide is that top speed fast enough, Thought brass turned around 4500 to 5500 when using carbide, with HSS I think 1500 to 3000,
But been many seasons now since my apprenticeship in engineering?
And like the weather, my mind is often foggy and clouded over.
But be worth checking it out, somewhere on the net must know.

 

[WoodchipWilbur]

Do you use carbide or hss?
If carbide is that top speed fast enough, Thought brass turned around 4500 to 5500 when using carbide, with HSS I think 1500 to 3000,
But been many seasons now since my apprenticeship in engineering?
And like the weather, my mind is often foggy and clouded over.
But be worth checking it out, somewhere on the net must know.

Me? I don't use anything at the moment! I am a veritable babe in arms - a mere suckling... From what I have read on this thread, I am anticipating using HSS. (From observing bell tuning at the foundry, they use HSS - and the bell (on a big vertical lathe) turns at about 0.2 per sec (or less). But that is a VERY different kettle of fish!)

It will be interesting to compare the machineability of my brass run-of-the-mill kid's bells with the rather different bronze (a whopping 22% tin makes it very hard and brittle) of a "real bell". The brass is my initial goal - working up to bell metal is a longer term project and learning curve, as it is with the casting process (where I am learning from a different set of gurus)!

 

[dangles]

Me? I don't use anything at the moment! I am a veritable babe in arms - a mere suckling... From what I have read on this thread, I am anticipating using HSS. (From observing bell tuning at the foundry, they use HSS - and the bell (on a big vertical lathe) turns at about 0.2 per sec (or less). But that is a VERY different kettle of fish!)

It will be interesting to compare the machineability of my brass run-of-the-mill kid's bells with the rather different bronze (a whopping 22% tin makes it very hard and brittle) of a "real bell". The brass is my initial goal - working up to bell metal is a longer term project and learning curve, as it is with the casting process (where I am learning from a different set of gurus)!

I have machined brass,bronze,silver steel,cast iron,aluminium and even a lump
of hardened lorry leaf spring on this lathe.

 

[WoodchipWilbur]

I have machined brass,bronze,silver steel,cast iron,aluminium and even a lump
of hardened lorry leaf spring on this lathe.

I've messaged you privately. Let's go for this!

 

[WoodchipWilbur]

Good to meet you, Dangles! It was a pleasure to collect your lathe - and the accompanying packets of extra bits of kit. It's in my workshop - and plugged in. I'm happy to say that it works as advertised. Now all I have to do is to learn how to use it!

I do have an initial query. The saddle is moved back and forward with the apron handwheel. Fine. Unless that is engaged with the leadscrew, it is free to move back and forwards and so the operation of the topslide mechanism seems to be quite irrelevant. If is IS engaged with the leadscrew then, of course, the whole lot sets off toward the chuck.
Should it be possible to lock the saddle in position? (If so, how?) or is the whole operation normally controlled by the apron handwheel? I'll keep reading - and may well find the answer for myself but the collected wisdom of you folk is never to be sneezed at!

 

[WoodchipWilbur]

I now have a fine mini lathe (thanks, Dangles!) - AND I'm getting to grips with it! But I have a suuplementary question...
HOW MINI IS MINI?

The lathe has a couple of chucks - they can both hold work up to c.3" diameter. There's a faceplate, too - that's over 6" (160mm) BUT...
Any tool in the post can only move out to about 25mm from the centre, meaning that I can only machine tiny bells (which is what I got it for).

Is this a lathe that limits me to 2" diameter - or (more likely, I hope!) am I missing a trick here?
(You can tell I'm more at home with the freedom of a wood lathe!!)