How strong is a mini lathe spindle

Hello all,

I know this may be a unusual question to be asking. but what I would like to know is, how strong, if this is the right word to use, is a Chinese made mini lathe spindle? Myford lathe spindles are rated at 40-50 tons high-tensile steel according to tony's lathe website.

lee

Hi Lee, "rated at 40-50 tons high-tensile steel" is a little abiguous, However such a referal is often a measure of tensile strength per sqaure inch, that is, the area of the cross section when subjected to a tensile load.

Given that mild steel is around the 25 tons per square inch mark, should give what you expect the minimum to be.

Regards Nick.

I found a calculator on the web that worked out a 10" steel pipe with.250" wall and an O/D of 1.250" has a yield load of about a ton if supported at each end.

I reckon a mini-lathe spindle has a bit more meat and much less length between the bearings and is probably better steel than 'pipe'.

I have no idea if that helps, but I'd guess you are talking a load of several tones to permanently deform a mini-lathe spindle - I think the cast headstock would break first.

The bearings are comparable to van-sized wheel bearings too.

I can't see how you could overload the spindle in normal use, even with a huge chuck and workpiece. A bigger risk would be damaging headstock and/or bed in the event of a big jam-up.

Neil

Thanks for the replies,

This is what I wanted to hear, though, I do wonder what they have actualy been tested at, the force before they gave out and buckled.

lee

Maybe the tensile strength figure is more relevant as an indicator of stiffness ?

M

Not relevant at all I know, but as a schoolboy I was enormously impressed by the crush strength of an ordinary Fletton house brick on a visit to Stewartby brick works.

It took 70 tons on an Avery machine before crumbling.

I think as the others have said, the headstock castings will fail long before any distortion of the spindle can occur. I doubt if your could even deliiver the power needed from the usual motor size these lathes are equipped with.

Brian

Not really. Stiffness is determined by the shape of the part and the Modulus of the material. To a first approximation the Modulus of all steels is the same regardless of what Yield or Ultimate strength the steel has.

I very much doubt the manufacturer wasted any time or money testing the spindle.

Regards,

Andrew

Hello John,

I am not sure, what do you mean by 'Advertising hype. Pure and simple' ?

Regards

lee

Why does it make a difference that it's Chinese made?

Am I right in thinking that the Mini-Lathe is based on an eastern european lathe of some description?

Martin.

Ok,

I recently own a 7x14 mini lathe , made in china, Quite frankly they are terrible, I cannot hide from saying this,their just tat, for the amount of work that's needed to bring them up to any sort of good quality, just hold onto your money, , also I found that they could still be described as a mini lathe but just made a bit bigger and they could still be sold at the same price., but then they know this, I could go on.,just so Glad I got a large proportion of my money back

So what I decided was to build my own, based on the concrete lathe but bit more refined.

I already have a practicably brand new mini lathe spindle and taper roller bearings that cost me nothing,also I have two  65 mm diameter hardened chrome Hydraulic shafts each being a meter long.

this is why I started the thread,, as this lathe will be somewhat bigger, I wondered what these mini lathe spindles can Handle.

lee

Edited By lee hawkins 1 on 09/01/2014 15:56:36

As a very happy mini-lathe owner I can only suggest that there are mini-lathes and mini-lathes, and many of the suppliers have greatly improved their quality control. Please don't judge them all by the same standard, though if you had a "bad 'un" I realise you won't risk being caught twice.

> I wondered what these mini lathe spindles can Handle.

Neil

I think you are getting "Fit for purpose" mixed up with "Fit for Purse"

Why is it that all the people who moan about these lathes buy one when for bit more money they can get a far better machine, but no they buy these are wonder why they don't perform the same as a more expensive one.

There is a reason a Ford costs 10K and a BMW costs 50K.

I know one guy who has 4 of these mini lathes, all converted to CNC, two even have bar feeders on them to take the material in 1 metre lengths. He has a niche product, I won't mention it as he likes to keep his product quiet but Ketan knows who I mean.

With these 4 machines he produces 13,000 to 16,000 parts per month, no typo per month.

He goes on at least 3 cruises a year, in fact he's away at the moment as I have parts to one of his machines to alter. So if they were that bad why does he bother ?

And wouldn't he have sourced some better machines ?

Let us know the breakdown cost of your concrete machine when you are done and were we can all source 65mm hardened hydraulic rods cheaply to build our own better machine at a comparable price to a mini lathe.

John S who frankly gets pee'd off by cheap customers buying even cheaper goods and then whinging.

Thanks for posting picture and replies

Thats looks like a quite heavy lump of metal, what rpm have you span up at?

Over the years I have had a couple of Myfords a Dalton and a Cromwell, all old Vintage lathes that some would call clunkers with all the years of use, they all still had that silky smooth quality feel., no way of getting this with the mini lathe I had., Fitted taper bearings metal gears that made it sound like a marble in a tin can, had to mess about with the circuit board ,it would keep hunting, I just got fed up with the thing.

lee

I must be honest, Lee,

i faced that lump on all 6 surfaces to make a T-slotted table (which I milled the slideways and t-slots for on the mini-lathe too) but I only ran teh lathe at about 60 rpm because of vibration (not attached to bench).

Taking too deep cuts at such slowspeed guess what happened ... yes I had to buy a new motor. But I think this was my inexperience, not a problem with the lathe. Just because you CAN make a deep cut t 7"diameter at 60rpm doesn't mean you SHOULD!

No problem these days though - I've fitted a 0.4kw three-phase motor and I suspect the lathe would take a full 1kw.

My concern with a bigger motor though is that a jam up could crack the headstock or twist the bed.

Neil

I know one guy who has 4 of these mini lathes, all converted to CNC, two even have bar feeders on them to take the material in 1 metre lengths. He has a niche product, I won't mention it as he likes to keep his product quiet but Ketan knows who I mean

And wouldn't he have sourced some better machines ?

John

He owns 4 of them, bought them for how inexpensive they are, standard quality of the lathe did not matter, he bought them for the sole reason for converting to CNC . he built the quality into them,

If I were converting a mini lathe to CNC the problems these mini lathes have would not of mattered.

John S, Do you own a mini lathe?

I am not a Cheap customer, who buys cheap goods, for 500 quid you can expect something that is worth 500 quid

having owned one of these mini lathes, to me they are not worth 500 quid,most probably, they are only worth what the dealer importer pays for them

John

I did not want to get on this subject of Bashing the Mini Lathe.