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Lathe improvements?

Old man playing with lathes.

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Niels Abildgaard26/11/2020 19:41:32
368 forum posts
150 photos
Posted by old mart on 26/11/2020 19:28:23:

From the photos, particularly the first, it looks like there will be very little left of the inner part of the screws when they are cut to clear the 50mm bore. The remaining flanges are all that will hold the jaws and the screws in the chuck.

Instead of 9 flanges supporting the jaw I will have seven.

No big deal when in 35 to 50mm zone.

For smaller diameters I will use the 100mm four jaw enlarged from 25mm hole to 36mm.It is lower mass and more manegeable.

II am still thinking I will ask the manufacturer to make a ligthweigth 125mm/50mm bore  four jaw with screws and claws from the 80mm model.

Nicer for old toads.

If a reader has a 80mm four jaw can You please measure distance from front face to underside of screw hole like on picture?

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Edited By Niels Abildgaard on 26/11/2020 19:43:20

Edited By Niels Abildgaard on 26/11/2020 19:44:07

Edited By Niels Abildgaard on 26/11/2020 19:44:54

Thor27/11/2020 04:48:28
1324 forum posts
40 photos

Hi Niels,

On my 80mm 4-jaw independent from ARC the distance is 29mm.

Thor

Niels Abildgaard27/11/2020 08:39:36
368 forum posts
150 photos
Posted by Thor on 27/11/2020 04:48:28:

Hi Niels,

On my 80mm 4-jaw independent from ARC the distance is 29mm.

Thor

Thank You Thor

On my normal 125 it is 36mm and mass is 5+kg.

With Your 29mm a independent adjustable four jaw 125mm dia slimline with 50mm borehole should be feasible with ca 4kg mass.Nicer and safer than 9kg for a standard 160mm version that has a 50 mm bore from factory.

Edited By Niels Abildgaard on 27/11/2020 08:40:30

Thor27/11/2020 10:18:14
1324 forum posts
40 photos

Hi Niels,

I have a lightweight (4.5kg) Indian 6 inch 4-jaw independent on my 290 lathe, the distance you asked is 31mm on the 6 inch and the chuck is about 45mm thick. As you say, the lighter chucks are easier to lift when you are old and have worn joints. I'm looking forward to see photos.

Thor

Finn Hammer27/11/2020 14:52:44
avatar
5 forum posts
18 photos

Thanks Niels,

That link to the gears merchant is very nice

Cheers, Finn Hammer

Posted by Niels Abildgaard on 16/05/2019 15:21:49:

Cheap gears

The original spindle gear is 40 teeth module one and leadscrew 80 teeth.

Niels Abildgaard27/11/2020 16:04:41
368 forum posts
150 photos
Posted by Thor on 27/11/2020 10:18:14:

Hi Niels,

I have a lightweight (4.5kg) Indian 6 inch 4-jaw independent on my 290 lathe, the distance you asked is 31mm on the 6 inch and the chuck is about 45mm thick. As you say, the lighter chucks are easier to lift when you are old and have worn joints. I'm looking forward to see photos.

Thor

Hi Thor

Do You have a link to this range of chucks?

A 150 or 160 chuck on a 180 lathe is a little risky if the corresponding 125 can be bored to 50mm and be under 4 kg.

Thor27/11/2020 17:49:05
1324 forum posts
40 photos

Hi Niels,

My Zither 6 inch independent was purchased from ARC some years ago, I believe that ARC doesn't carry Zither chucks any more. I use the 6 inch 4-jaw quite often and consider it good value for the money I paid. ARC lists a slim body 2.5 inch under Clearance Items, others may still stock them.

Thor

Niels Abildgaard27/11/2020 19:25:22
368 forum posts
150 photos

Hi Thor

It went better than expected to enlarge my 125mm four jaw.Trick was to keep screws fixed by blocking the jaws.

wp_20201127_001[1].jpg

wp_20201127_002[1].jpg

Thor28/11/2020 04:50:13
1324 forum posts
40 photos

Hi Niels,

Thanks for the photos, well done. Will enlarging the hole interfere with the jaw adjusting screws? I see your chuck can be mounted on a backplate from the front, makes things easier.

Thor

Niels Abildgaard28/11/2020 05:55:49
368 forum posts
150 photos
Posted by Thor on 28/11/2020 04:50:13:

Hi Niels,

Thanks for the photos, well done. Will enlarging the hole interfere with the jaw adjusting screws? I see your chuck can be mounted on a backplate from the front, makes things easier.

Thor

The four jaw screws were cut in same operation as the chuck body.

Very healthy diet for a scrapped carbide cutter ,this mixture of cast iron and casehardened steel

wp_20201128_002[1].jpg

Andy Pugh28/11/2020 10:52:23
59 forum posts
1 photos

Posted by Niels Abildgaard on 28/11/2020 05:55:49:

The four jaw screws were cut in same operation as the chuck body.

I was a bit surprised by that. It isn't generally very difficult to get the screws out, and then the inside ends could be finished off neatly on a lathe.
Just remove the jaws and then tap the forks back with a punch. They are often only retained by the backplate.

Niels Abildgaard28/11/2020 15:52:19
368 forum posts
150 photos

The screw forks are more fixed than the violence and screwdriver misuse that I like to apply.

I have cleaned up the boring and screws so that 48mm will pass and mass is 4.3kg.

wp_20201128_003[1].jpg

Niels Abildgaard08/01/2021 19:51:35
368 forum posts
150 photos

wp_20210108_002[1].jpg

 

A Boxford VSL escaped my inhumane experiments and is in a good home where new owner also has pre WW2 Citroen Traction Avant.

Very classy company for a Boxford.

My cheap 210 that came with 38mm spindle bore has cut first swarf on its own new 50mm bore spindle.

It went very well but bearings are running much to hot.

It is very instructive to have a Watt meter before converter.

I made motor run 2000 rpm(Belt to spindle 4 to 1 ca) without belt and used 20 W.

With belt on but not cutting and same speed consumption was 190W and belt and bearings became much to hot..

Spindle nut was loosened and a hammer and woodblock worked and consumption sank to 120W.

Tomorrow the 125mm four-jaw with 48mm hole will be put on and we will try some real parting off.

wp_20210108_003[1].jpg

Edited By Niels Abildgaard on 08/01/2021 19:56:50

old mart08/01/2021 21:52:20
2472 forum posts
169 photos

Common spindle preload setup with taper roller bearings is just enough to end up warm to the touch but not hot, after 15-20 minutes at top speed unloaded. This would probably hold good with angular contact bearings as well.

Hopper09/01/2021 00:16:30
avatar
5069 forum posts
114 photos
Posted by Niels Abildgaard on 08/01/2021 19:51:35:

wp_20210108_003[1].jpg

Edited By Niels Abildgaard on 08/01/2021 19:56:50

For goodness sakes! Mount that lathe and massive solid granite base block on a strong work bench before you hurt yourself.

That spindly Ikea piece of living room furniture was never designed to take that weight safely. It could collapse any minute now.

You are a danger to yourself and those in the apartment below you.

Ady109/01/2021 09:18:41
avatar
4138 forum posts
576 photos

Some next level stuff Niels, very interesting

Hopper is right btw, buy a nice strong bench today and move that lathe before something bad happens

edit: best to do it before parting off begins

Edited By Ady1 on 09/01/2021 09:20:29

Niels Abildgaard09/01/2021 09:45:05
368 forum posts
150 photos

Table was tested by two neigbours and their child rocking sideward in unison.Looked funny and no problem .Human mass 1.5 times diabas plus lathe.There is no neigbours underneath unless chineese count as neigbours.

It was much more alarming that the roller cages rubbed the bores.I filed them down and have no ultrasonic bath.

First five minutes sounded awfull but now they are OK and power falls steady and is now 80W down from about 200 yeasterday.temperature around 37 degree and I have put a chair and another miserable and cheap secondhand table as first line of defense against collapse.

I think world is quite a pleasant place for old men.

Lathe ,diabas and table are united by two M12 all-threads.

wp_20210109_001[1].jpg

Edited By Niels Abildgaard on 09/01/2021 09:47:55

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