Mellor lathe.

[Richard.]

Yes. It did improve a fraction . It's getting feed rate down that's the difficult bit. Even using the front screw the biggest gear being 127

You must be able to set up the gear train to slow it right down.

 

[God mode restorations]

You must be able to set up the gear train to slow it right down.

Am slowly going through it now.

 

[God mode restorations]

I have been doing some research in to tool inserts. A corner radial from 0.2mm to 1.2mm depending on chip breaker. Is it better to go with a small radial or the larger. Or is it a case of different materials need different radius. Just starting to get to grips with tooling and radius

 

[Hood]

Here are a couple of quick CAD drawings showing the effects of a CCMT with 0.4 nose rad.
This one is at 0.2mm/rev

This one is 0.1mm/rev, afraid pics are a bit different sizes but you should still get the idea.

For good info on all aspects of Inserts have a read of the Sandvik site, this bit deals with nose rad for boring bars but the same is true of OD turning.

https://www.sandvik.coromant.com/en...se-radius-and-depth-of-cut/pages/default.aspx

The main page is here

https://www.sandvik.coromant.com/en-gb/knowledge/pages/default.aspx

 

[zx9]

Here are a couple of quick CAD drawings showing the affects of a CCMT with 0.4 nose rad.
This one is at 0.2mm/rev

View attachment 140844


This one is 0.1mm/rev, afraid pics are a bit different sizes but you should still get the idea.

View attachment 140845



For good info on all aspects of Inserts have a read of the Sandvik site, this bit deals with nose rad for boring bars but the same is true of OD turning.

https://www.sandvik.coromant.com/en...se-radius-and-depth-of-cut/pages/default.aspx

The main page is here

https://www.sandvik.coromant.com/en-gb/knowledge/pages/default.aspx

Thanks @Hood seeing your drawings makes it very clear, as a novice lathist I assumed that a small nose radius would be good for a small lathe. Seeing that was a 'light bulb' moment and it is so obvious now that small radius = very easy to accidentally thread the work if the feed is too fast.

 

[Hood]

You still have to be careful that you don't go too big on the nose rad on a small lathe, 0.4mm would be what I would tend to use. If you go too large then you could end up with rigidity issues.
Feed in combination with nose rad is a major part of getting a good surface finish but so is speed, DOC, rigidity of the machine etc etc. It is all a balancing act on small machines and a positive insert geometry will likely be the best, it is a weaker insert but on a small lathe you likely don't have the rigidity or power for a negative insert.

 

[eLuSiVeMiTe]

Ccmt06 or 09. It’s the ones I use.
I’ve got tools that allow all 4 corners to be used.
I buy the good ones only now as they cut so much nicer than cheap ones.

Apparently the odd angles fair better with intermittent cuts.

 

[Richard.]

Thanks @Hood seeing your drawings makes it very clear, as a novice lathist I assumed that a small nose radius would be good for a small lathe. Seeing that was a 'light bulb' moment and it is so obvious now that small radius = very easy to accidentally thread the work if the feed is too fast.

A small rad is definitely the way to go on a small lathe. You won’t cut a thread if your feed speed rates are right. I use 0.2 and 0.4 which are tiny radius tips but they finish up just fine.

 

[Hood]

A small rad is definitely the way to go on a small lathe. You won’t cut a thread if your feed speed rates are right. I use 0.2 and 0.4 which are tiny radius tips but they finish up just fine.

Even on my biggish lathes I use a small rad for finishing, 0.4mm usually but occasionally even go down to 0.2mm. My go to finishing feedrate is usually 0.15mm/rev on the CNC, my roughing feedrate is usually 0.2 - 0.3mm/rev.

 

[Richard.]

Even on my biggish lathes I use a small rad for finishing, 0.4mm usually but occasionally even go down to 0.2mm. My go to finishing feedrate is usually 0.15mm/rev on the CNC, my roughing feedrate is usually 0.2 - 0.3mm/rev.

I don’t really have a roughing feedrate on mine. I can’t be bothered swapping wheels around and it’s not gonna break any speed records
I just drop the speed and take a bigger slither
The feed rate always stays the same.

 

[Hood]

I don’t really have a roughing feedrate on mine. I can’t be bothered swapping wheels around and it’s not gonna break any speed records
I just drop the speed and take a bigger slither
The feed rate always stays the same.

Yes, change wheels are a PITA compared to gearboxes or even better CNC but they do the job and you can always find a way to overcome shortcomings.
Being self taught it has all been trial and error for me and I have found the things that work best for me, some things may seem weird to others but they work for me so that is the way I do it. For example I tend to use an SVJBL for facing and finish turning on the CNC. Now that is not an ideal tool for facing but on the CNC the most I take off is 0.5mm and usually just 0.2mm as it is just a cleanup so it works well for me.

 

[zx9]

Even on my biggish lathes I use a small rad for finishing, 0.4mm usually but occasionally even go down to 0.2mm. My go to finishing feedrate is usually 0.15mm/rev on the CNC, my roughing feedrate is usually 0.2 - 0.3mm/rev.

Hum the Drummond lists 130 tpi and 160 tpi (from memory) as the fine feeds which is ( a very approximate ) 5.2 and 6.4 tp mm or 0.19 and 0.15 mm per rev if I have worked it out correctly. Which would fit in with your 0.15 mm/rev and co incidentally does give a nice finish with a .2mm rad insert on a one or two inch diameter bit of steel be it EN1 or silver steel does not seem to matter.
That would be at about 500 or 700 rpm I have not worked out the gearing yet as it is a non Drummond lay shaft and the ratios of the lay shaft pulleys do not match those on the spindle.

 

[Richard.]

Here’s an ml10 “rougher” cut.
It’s the quickest way I’d dare to shift metal with that little lathe.
Neutral rake insert, 0.4 nose rad 145rpm and the DOC is 0.5mm at a time. It’s not that rough tbh. Rougher than I would want to give to a paying customer. I keep my high rakes 0.2 rads for those final finishing passes to get that mirror finish.

 

[Dieselman 63]

How small is a small lathe? I know the Bantams and boxfords are considered small but the ML10 is tiny in comparison!

 

[eLuSiVeMiTe]

How small is a small lathe? I know the Bantams and boxfords are considered small but the ML10 is tiny in comparison!

If you can pick it up whole its a small lathe
Wouldnt go by swing either. Current lathe swings 1/4 inch more tham my ml1.

 

[God mode restorations]

If you can pick it up whole its a small lathe
Wouldnt go by swing either. Current lathe swings 1/4 inch more tham my ml1.

Can't pick mine up. Not at 560 kgs

 

[Richard.]

How small is a small lathe? I know the Bantams and boxfords are considered small but the ML10 is tiny in comparison!

Ml10 is a fraction of the size and weight of a boxford.
If I disconnect the motor I can carry my lathe

 

[Dieselman 63]

Can't pick mine up. Not at 560 kgs

Heavier than mine then. 454kg as quoted in the catalogue, or 360kg on lathes.co.uk . Not entirely sure who to believe, all I know is it’s beyond my capabilities!

 

[Hood]

All depends on the lathe, some small lathes are very rigid others are like they are made of cardboard.

 

[Richard.]

It’s all very well having big fancy kit but the important bit is the work leaving the jaws.
Take optima for example. His lathe is smaller than mine yet it turns out work that would put most of these big beasty lathe owners to shame.
Size matters a lot but skill matters more.