Milling attachment for mini lathes

[opochkaParticipant @opochka]

Hi all,

I am a mechanical designer, I am working on the development
of a compact powered milling attachment for an Amadeal CJ18A mini lathe,
which I currently use.

The attachment does not require any modifications to the lathe at all,
it simply drops into place and bolts down to the flat top face on the compound slide where the tool holder block normally lives.

Designed so that it can drill holes and slots through shafts, mill keyway slots,
flats and splines along shafts, also face milling, face slots, counterbores,
easy equi-spaced flange hole drilling up to 120 mm pcd., using an indexing disk that bolts on behind the chuck and a link bar that bolts to a saddle clamp to hold it all rigid.

Using the compound slide angle adjustment, the unit will also drill holes at silly angles into the face of turned parts.

But before I get carried away, I was wondering if anyone would actually be interested in such a tool for a mini lathe,
as it would do 80% of the work that a mini vertical milling machine can do,
at less than half the price.

Also, I realised that the milling attachment may also fit other types of mini lathes, but I do not have their dimensions,

would some kind fellow model engineers who own a Grizzly, Harbour Freight, Sieg, Clarke, etc
7 x 10, 7 x 14 lathe please PM me.

regards Dave Archer

[opochkaParticipant @opochka]

[Nick HulmeParticipant @nickhulme30114]

I use a milling attachment from a Record/Toyo/Manix ML360 mounted to the cross-slide and occasionally find it invaluable for keyways, odd angled holes and interrupted material removal around a diameter.

If yours could also mount to the bed then 3-axis milling would be better facilitated, for ordinary milling by mounting a column to the slide you are amplifying any play in the carriage and slide. Rigidly mounting the column and using the carriage and slide with a milling table on it gives better results,

Regards,

Nick

[Bob StevensonParticipant @bobstevenson13909]

Interesting…….I think you can safely assume that there is an interest as these machines are very common.

 

I am also engaged on the same task, but from a horological viewpoint. The main problem with milling using a vertical slide is that the mini-lathes are notoriously lacking in rigidity. As you will have seen, the cross slide is perforated by a large cut-out to facilitate the 360 degree top slide. This is a serious drawback to rigidity and once a new, thicker unperforated cross slide top if fabricated the whole machine is fairly vastly improved.

 

Obviously, the way to go is to replace the top slide with a powered spindle and mill into the chuck/lathe spindle.

 

For your info there are effectively TWO types of these lathes, namely those made by 'Sieg' factory and those made by 'Real Bull' factory …there is/was a third maker but their lathe is very uncommon in Europe and sold under the 'craftex' lable in Canada/Australia(?) The main two have differences mainly in the cross slide details.

 

The lathe I am using is a 7×14 'conquest' supplied by Chester machine tools and made by 'Real Bull'…so I can supply measurements for that type.

Edited By Bob Stevenson on 16/09/2016 14:33:24

Edited By Bob Stevenson on 16/09/2016 14:36:28

[mechman48Participant @mechman48]

… Also, I realised that the milling attachment may also fit other types of mini lathes, but I do not have their dimensions,

would some kind fellow model engineers who own a Grizzly, Harbour Freight, Sieg, Clarke, etc
7 x 10, 7 x 14 lathe please PM me.

regards Dave Archer

As I read it are you planning to make these designs for your own benefit / forum readers / for sale, if so what pricing are you considering?… or have I got the wrong end of the story?

George.

[Jonathan GarsideParticipant @jonathangarside40968]

George

I think the OP has indicated a price in his posting "at less than half the price of a mini vertical milling machine"

Jonathan

[Ady1Participant @ady1]

When Drummond did it the whole gubbins cost more than a new Drummond lathe

[opochkaParticipant @opochka]

Posted by mechman48 on 16/09/2016 17:08:29:

… Also, I realised that the milling attachment may also fit other types of mini lathes, but I do not have their dimensions,

would some kind fellow model engineers who own a Grizzly, Harbour Freight, Sieg, Clarke, etc
7 x 10, 7 x 14 lathe please PM me.

regards Dave Archer

As I read it are you planning to make these designs for your own benefit / forum readers / for sale, if so what pricing are you considering?… or have I got the wrong end of the story?

George.

Hello Bob and George,

I have had the Amadeal CJ lathe for well over a year.

I live in a small flat and do not have space ( or money ) for a £ 800 mini-mill and table, tooling and everything else that goes with it, although I often need parts made that requires the use of a small mill.

Slots, key ways, through holes, splines, etc.

I have to ask a local engineering company to do these parts for me, which rather destroys the concept of home model engineering.

I realised that thousands of these CJ18 mini lathes are being sold each year to budding model engineers, and also that most of those buyers will be in a similar position to myself.

The milling attachment will not be a flimsy vertical mill, sticking a long way up into the air, but horizontal, and the milling cutter / drill / slot drill, will be held in an ER16 collet, right up close to the tool post centre bolt, and so will be extremely rigid, driven with a 500 watt motor, with infinitely variable speed control, built into the attachment as one complete modular unit.

The power control electronics will be in a separate box screwed to the wall behind the lathe.

I am in the process of having investment castings in solid Aluminium for the main body made, have applied for a Registered Design, and I am waiting for the working model to be completed to start the application for a Patent.

Because of the Patent application, this means that I cannot show a video of the prototype attachment working, which is a bit annoying.

As I read it are you planning to make these designs for your own benefit / forum readers / for sale, if so what pricing are you considering?… or have I got the wrong end of the story?

Yes, this unit will be for sale, as a complete kit when completed. I think that I can keep the price around £ 300.

Primarily for the CJ18 lathe owners, because I have already sussed out all the dimensional problems, but maybe later for the other variants of mini lathe out there.

regards dave

.

[Bob StevensonParticipant @bobstevenson13909]

Dave,

I can't see how this device can have much monetry value (to you) because even were you likely to come up with something truly novel it would simply be duplicated by the same Chinese factories that make the mini-lathes, and much else besides. You are very unlikely to be able to defend any patent, or even, come to that to identify the actual copiers as they will simply hide behind the usual complexity of Chinese business and exporting function…….

Further, you are VERY unlikely to obtain a patent as what you are planning exists and has for some time….simply take a look online and you will find the Hemingway item (Step up mill) and several others. Even before that there was/are tools of similar function such as the Potts spindles in their several forms. Not trying to be obtuse here but you really do have things stacked against you with the patent route for any machine tool or device,…and don't even think about the cost of defending any patent that you might be (very) lucky to obtain. patent applications, as several people here can tell you from practical experience are a nightmare set of traps and pits for the unwary and several of the said 'pits' quickly turn into money pits……..Apart from all this you need to have come up with something truly 'novel'….without wishing to be unkind that is extremely unlikely as you can see for yourself with the aid of Google (just about your only friend in this!)

One of the great things about the Chinese mini-lathe is that it's cheap(ish) and exists in large numbers, thus offering a large market with a requirement for cheapness. if you can offer a practical cross slide mill (or kit of bits) for a low price you can sell some, at least until the chinese take notice…..

[mechman48Participant @mechman48]

Ok got you, wish you well in your application.

[JasonBModerator @jasonb]

I suppose the other thing you need to consider is that this milling spindle will be limited as to what it can do compared to a small mill, you wil have to have a lot of features to make people spend out £400 for a stop gap as most will likely want to go the whole hog at some time and get a mill.

What are you going to do about control of depth of cut? The mini-lathe carrage handwheel is not that accurate of delicate if you want to put on a few thou of cut.

J

[opochkaParticipant @opochka]

Posted by Bob Stevenson on 16/09/2016 19:39:23:

Dave,

I can't see how this device can have much monetry value (to you) because even were you likely to come up with something truly novel it would simply be duplicated by the same Chinese factories that make the mini-lathes, and much else besides. You are very unlikely to be able to defend any patent, or even, come to that to identify the actual copiers as they will simply hide behind the usual complexity of Chinese business and exporting function…….

Further, you are VERY unlikely to obtain a patent as what you are planning exists and has for some time….simply take a look online and you will find the Hemingway item (Step up mill) and several others. Even before that there was/are tools of similar function such as the Potts spindles in their several forms. Not trying to be obtuse here but you really do have things stacked against you with the patent route for any machine tool or device,…and don't even think about the cost of defending any patent that you might be (very) lucky to obtain. patent applications, as several people here can tell you from practical experience are a nightmare set of traps and pits for the unwary and several of the said 'pits' quickly turn into money pits……..Apart from all this you need to have come up with something truly 'novel'….without wishing to be unkind that is extremely unlikely as you can see for yourself with the aid of Google (just about your only friend in this!)

One of the great things about the Chinese mini-lathe is that it's cheap(ish) and exists in large numbers, thus offering a large market with a requirement for cheapness. if you can offer a practical cross slide mill (or kit of bits) for a low price you can sell some, at least until the chinese take notice…..

Bob,

I completely agree with everything that you have said above about patents !

I know that the device will eventually be copied if it gets out there on the market.

The patent application will be for how the device is actually controlled, not for anything with the unit.

It will be just a provisional patent, until it lapses.

This happens to every invention that was any good at all……..Ask James Dyson !

I will be relying on the Registered Design, to get my name stamped on it, but only for the UK.

I know that if it starts to sell, there will be a short good time for sales, and then will come

the inevitable take-over by cheaper imports.

I will just have to move on to some new design for something else !

dave

[opochkaParticipant @opochka]

Posted by JasonB on 16/09/2016 20:08:16:

I suppose the other thing you need to consider is that this milling spindle will be limited as to what it can do compared to a small mill, you wil have to have a lot of features to make people spend out £400 for a stop gap as most will likely want to go the whole hog at some time and get a mill.

What are you going to do about control of depth of cut? The mini-lathe carrage handwheel is not that accurate of delicate if you want to put on a few thou of cut.

J

Hello Jason,

I suppose that it could be seen as a Stop-Gap unit, but it will in fact do just about all operations that a model engineer would normally need or come across.

It cannot do some of the things a mini-mill can do, like milling faces flat or cutting out square holes in flat plates, milling blocks to size, etc.

But it will easily do things that would be a struggle to set up on the mini-mill.

Milling splines along a shaft in the chuck, can do flange holes, without all that trigonometry.

will be supplied with an indexing disk, locking clamp, and a saddle stop.

Depth of cut will be controlled by the cross slide and compound slide indexing dials, the saddle will be normally locked, unless making longitudinal slots in tubes for example, then a saddle stop will be used to

control the length of the slots.

It is not intended as a direct replacement for a mini-mill, but to complement one, if you have one, or do many of the things that a mini-mill does, if you don't have one, or don't have space for one.

It is possible that this attachment would be all someone would need to complete their jobs, instead of spending a lot of money on buying a mini-mill.

regards dave

[MuzzerParticipant @muzzer]

Don't waste your time with patents or even registered designs. Just get on with developing it and if it ever sees the light of day, you may some of your investment back by selling the kit of parts or the finished item. But I wouldn't put my name down on that Porsche yet.

Dyson's story is a marketing success, not an engineering one. And the vast majority of patents cost lots and make little or nothing.

[Neil WyattModerator @neilwyatt]

All teh generic Mini Lathes are to basically the same design, most built by SIEG and some by Real Bull, although tehre are many variations in detail from circuit boards to bed length, some obvious to the casual bserver, some obscure.

Differences in the major dimensions are unlikely to exceed normal manuvfacturing tolerances.

Neil

[Author]

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