Mini lathe transmission replacement

Gallery, Projects and General > How do I??

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PekkaNF:
Bogs,

I haven't use this particular lathe, I have one 60kg french made cheapie and then some heavier ones.

While I agree on big picture ("if you want to start machining larger pieces, then you need to go for a larger lathe" et.al.) with you I disagree slightly on 3" category.

* Any tool should be able to tolerate reasonable use and some misuse. This reasonable should be defined by manufacturer.
* If machine has serious not so obvious limitations that should be stated on the spesification.

If you can chuck 7" billet on 7" lathe and there is no indication (maybe there is on the user manual?) that you can only turn e.g. 2" of free maching steel, 3" aluminium with 1 mm2 swarf then what we are left with?

I don't think plastic gearing is very elegant fuse against shock loads. I would think plastic shear pin might be more apropriate.

I'm no way expert in judging what size of work is apropriate for this size of lathe, but for me it is: If the tool tip is towards the centre from the bed way, then it should be fine.

There seems to some trouble on gearing of smaller lathes and mills, I'm having hard time beliving that it is all end users fault. I have no information on quality of the design of these, but I would imagine that very little money is used design to keep costs down.

Half of the fun of this hobby is to see if our tools can be modified and improved, sometimes they come out satisfacory, sometimes it turns to a learing process, which is't too bad either.

I'm considering hacking one taiwanese Myford ML10 (or something) copy. It's missing all moving parts on back gear, belt drive is shot, missing some gear to cut screws and a chuck is clunker. Probably could salvage it with some timing belt, AC-motor and a VFD. I'm not looking to make it beefier just more special, maybe to turn parts between centres or to take ER25 collet chuck.

Pekka

Bogstandard:
Pekka,

I will not argue over this issue, if you want to ignore many years of design and machining experience, and if you think you are better than the original machine designer, you just go ahead and do whatever you want.

There is a great difference between doing minor mods to a machine to get it to work better, and what you are trying to do, which is to take it beyond it's already designed limitations.

Bogs

lordedmond:
I to agree with John ( Bogs)

with the smaller typer of lathe a good guide is what can you turn above the cross slide not the bed thats the more sensible cutting dia. IMHO

yes my myford S7 big bore can swing 9 inches in the gap but and its a big but I have back gear down to 25 rpm and a 2 hp inverter fed 3 phase motor on the back so it don't stall :)

another point if I went to a Hardinge or Monarch My lathe would feel punny :(

Above all enjoy your machines and listen to them they will tell you a lot

Stuart

jim:
i've got the plastic "sacrificial" gear in all my machines. the lathes have never given any trouble, on the mill it has done one plastic gear.

the gear on the mill went after an hour and a half of fly cutting some lathe tools to size.

with the benefit of hindsight, it was abuse that bust that gear.

i think that the reason the lathe plastic gears have never gone wrong, is down to being a skilled turner!

websterz:

--- Quote from: Bogstandard on June 06, 2011, 10:16:43 AM ---Pekka,

I will not argue over this issue, if you want to ignore many years of design and machining experience, and if you think you are better than the original machine designer, you just go ahead and do whatever you want.

There is a great difference between doing minor mods to a machine to get it to work better, and what you are trying to do, which is to take it beyond it's already designed limitations.

Bogs

--- End quote ---

Don't hold back Bogs...tell us what you really think. :lol: :wack: :hammer: :poke:

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