Lathe improvements?

A new chinese precission version were just the thing for old toads.

Is that the standard M-Type 4jaw or something special? I have the regular 4 jaw on my Drummond and it is a nice slim body but never thought about the gap relationship.

.

It looks [in Ady’s posted advert] remarkably like what became the Myford special that Burnerd produced

... and the text about the reversible jaws seems to describe the style which became the de-facto standard.

I wonder what “common pattern” Drummond was using as its benchmark

MichaelG.

The Mega 920 versus Boxford stiffness comparison from 30 of march can maybeebe used again.

Many years ago I succeded in parting 100mm mild steel without trouble on my Boxford.

It is tempting to make a new spindle for my new 920 without any modification to headstock.

Distance from cutting point to first bearing is 110mm on the 920 and 140 on Box.

Bearing interdistance is 140 and190mm

Soft part of Box spindle is 36mm/19mm and the new 920 spindle is 40mm/28mm that is Box bends 1.26 times 920 .

length between bearings makes box 1.84 times more sensitive.

thecutting load makes spindle bending moment 1.28 higher for the Box.

For same cutting load the working point evasive movement will be 1,28 times 1.26 times 1.84 times 1.28 equals 3.8 less for the new two bearing 32908 920 spindle compared to my old boxford that was not bad.

I have just saved my self a lot of trouble.

My son has bougth a Quantum 310 910 lathe and I can have my beloved Weiss Mashinery 250 750 with Morsecone 4 back.That was up to now my best bid for an old geezer ideal lathe.

In the meantime I have worked on my Maximum Capacity-Minimum Volume version of Weiss 180/210 cheap as dirt lathe.

It consist of bed and sled from a 180/300 and headstock from a 210/400 and a 48mm bore spindle in some slim conical roller bearings.

The screwcutting and feeding arrangement has cost me headache but I am sure it can be handled now.Screwcutting from 0,4 to 2mm pitch comes easy and a single fine feed will do until I can make an Adjust as You cut version.

It needs to stop immiately when spindle does.

Edited By Niels Abildgaard on 24/08/2021 21:24:32

The gear wheels scheme is illustrated here

The fine feed via 80 teeth on spindle

First Compound 17/80

Second Compound 15/84

Leadscrew 2mm pitch and 100 teeth

Result can be calculated thus:

80multiplied by 17multiplied by 15 multiplied by 2  divided by 80 divided by 84 divided by 100 equals 0,o6mm per rev.

I would really prefer to use a 90 t gear instead of the 84 so if someone is in for a swap let us both benefit.

I have some funny gear numbers from aproximate imperial pitches on metric leadscrew and do not need them..

Let me know if You need.

For pure intelectual fun what imperial pitches between say  12 and 50 threads per inch are most important?

Edited By Niels Abildgaard on 24/08/2021 21:19:36

Edited By Niels Abildgaard on 24/08/2021 21:21:22

Edited By Niels Abildgaard on 24/08/2021 21:22:07

Two further pictures and some thoughts (in German).

Try to click two times the pictures in the German website.

The resolution from my handheld ,8 year old Nokia phone in indoor daylight is astonishing.

German version

I am trying to get the moral fibre to part off the heavy walled pipe shown in one of the pictures.

Edited By Niels Abildgaard on 26/08/2021 12:57:13

I would start with decent tailstock support

You must be joking

Hi Niels,

Re your narrow chuck, here is my own design narrow four jaw 6 inch chuck. The body thickness is 30mm. The jaws are guided by an oval gib that can be adjusted to eliminate slackness in the jaw guidance.

Alan

Posted by Alan Jackson on 26/08/2021 18:11:19:

Hi Niels,

Re your narrow chuck, here is my own design narrow four jaw 6 inch chuck. The body thickness is 30mm. The jaws are guided by an oval gib that can be adjusted to eliminate slackness in the jaw guidance.

Alan

Congratulation on work of a genius.

I have used hours to come up with something as good and failed.

How do You restrain the four jaw screw from coming out?

Edited By Niels Abildgaard on 26/08/2021 18:25:08

Edited By Niels Abildgaard on 26/08/2021 18:28:51

Hi Niels,

Thank you for your kind comments. The screws are secured by locked screws that can be reached inside the bore.

Alan

picture or sketch please?

Hi Niels

If you zoom up on the second photo you can see the screw heads in the chuck bore.

Alan

Thank You.

Am still confused but at a higher level.

Do not bother

Some high resolution stills and first cutting video.Performance is not impressive.

First cut Monster Mini Lathe

First parting of.44mm Heavy wall pipe, C45 150 rpm.

Iscar Tang-Grip inserts 1.4 and 3mm.

Limit is belt slip so if I want to part 88mm I will have to make and fit a 215mm spindle belt disc.

somewhat better resolution can be seen here:

Parting off

The lathe is back in 180 version with 27 mm hole and I dared to try some parting that went very well.

Iscar TAG N2J tipand blade and blade holder from China.

200RPM and nice mild steel C45..

If the manufacturers did some very small and not expensive changes it could become a very potent hobby lathe.

Parting off chinese mini lathe

A scrap-ready 920 lathe is in for a surprise.

30 and 50mm hole spindle,electric leadscrew from Numobams and sewing mashine motor 1500W also from China.

If You doubleclick link You will see a demolished house in background.

Our small town are divided what comes next:

Green eccological Kindergarten or funny house with lively ladies and lathes.

Next fun house lathe?

Double clikc for better resolution