Lathe improvements?

I have speculated for years on how to maintan alignment between spindle bearings when I modify utterly useless hobby lathes with 62mm bearing holes.

A short sequence of pictures show my latest proposal

Bearing enlargement

How about a line-borer?

This UK company sells or hires them, and may do so in Europe. (Their website is multi-lingual.)

I'm sure line-borers are available on the Continent too. No idea how much they cost or how hard they are to set up though.

Dave

Let's think a little further outside the box...

It's often easier to locate things accurately than to machine them accurately, or to make sure features are accurately positioned when machining (unless you have a jig-borer, etc. in your shed). Accurate location may involve just simple metrology, and/or the production of simple but accurate jigs and little force needs to be applied. (Also, nothing's whirling around, and you're not removing material you can't put back...)

You could bore out whatever is to receive the bearings, roughly and oversize, then effectively cast the bearings' location with one of the filled epoxies (Moglice?). If the bore and bearings are thought of as a negative, a positive can be turned, and set in the desired position, within the rough bearing housings, and the gaps filled with epoxy mix. The resulting housings will be as accurate as you made your 'positive' pattern and positioned it. (Just be careful you design it so it can be removed...).

Or mount the head casting onto the carriage of one of the other lathes and use a big between ctrs boring bar then the lathe just becomes a horizontal borer.

There is a special low melting point alloy which would be ideal for this:

https://flowxrgdotcom.files.wordpress.com/2011/07/new-method-of-building-lathes.pdf

The head castings on these machines are very simple, making a whole new head is probably not outside the realms of possibility.

Andy - interesting article, duly downloaded. Thanks for sharing it. I'll read it tomorrow, it's bed-time here! If we're branching out into casting entire headstocks - or more - there's also granite-filled epoxy (and other fillers) and concrete. Too many possibilities, not enough time...

Edited By Kiwi Bloke on 28/06/2023 12:27:14

It wouldn't really be branching-out for me.

http://bodgesoc.blogspot.com/2015/12/Holbrook3.html

and

https://bodgesoc.blogspot.com/2016/01/holbrook5.html

I actually think that a replacement head casting could be line-bored on the lathe itself.

1) Devise a means of mounting a boring bar to the tailstock quill. I have seen 3-jaw chucks for tailstock mounting, and I have an ER collet in bearings for a similar purpose.

2) As well as the head casting, have a cup-shaped casting made that can bolt on the back of the new casting to guide the boring bar. This could be machined on the lathe prior to dismantling it.

3) <handwaving> machine the head to bed mating surface

4) Set up the boring bar true to the bed, adjusting the steady bearing in (2) until a dial indicator travelling on the carriage indicates dead true. You now have an accurate spindle axis, aligned with the tailstock.

5) <more handwaving> somehow drive the boring bar.

6) Use the tailstock to feed the boring bar to machine the bearing bores and registers.

Hello and thanks to all for proposals.

Kiwis last remark sums my mental blockings perfectly. (Epoxy everywhere )

I have gone to bed every evening for years hoping to have the smashing idea when I wake up.

In vain so far.

The shown thing with two absolutely concentric surfaces (62mm outside to fit old bearing bore) and (cupseat 90mm inside for new bearing) is the most realistic after years of scheming.

Dog and me are to old for travelling but it could be a nice trip to China and se if I could talk someone to try

In headstock production cost it will be peanuts and spindle  a few dollars more.

The line borer would have made me a dream job

:Travel around world with dog in a Gypsy van and make useful lathes of Boxfords and Southbend  without removing headstock.

Edited By Niels Abildgaard on 28/06/2023 20:43:18

Edited By Niels Abildgaard on 28/06/2023 20:48:19

Andy - found your blog and downloaded most of it for future reading and enjoyment. At first glance, all one can say is blimey! It's truly awesome work (in the true sense of the word).

It's just the sort of thing I'd like to see in model Engineers' Workshop. I think I will probably let my long-time subscription lapse - the mag has become so dumbed-down, and the wholesale lack of proof-reading annoys. There's amazing stuff to be found on the 'net - if one has the time to search - but there's little to amaze in MEW these days. Pity.

Woke up this morning and have a new solution.

I am really to old to make new spindle docks and spindles and one can buy from a fast guy Ali in china a complete 38mm hole 210 headstock with 1100W motor.

I like the bed and slides of the 920 more than the 210 .

I will try to cross breed a litle.

You can find link on the german site I pointed to yesterday morning with all the coloured sketches now not longer relevant.

But fun to scheme.

Have prepared a marriage between an old 920 bed and a new 210 headstock but cannot decide which bride.

Please advice me.

Choice?

Some more thoughts

How to arange

I ordered and payed a headstock with 38mm hole spindle for 180/210 lathes 9 july and expect to receive it from danish customs tomorrow.

This will be put on a 920 lathe and if I get round to it will get a spindle with 48mm through hole and 125mm flange.

It is a shame to scrap the 920 headstock and maybe I can exchange the front bearing (35/62/17mm) with a (65/90/17mm)

Glued and screwed

My never ending story

Keep up the amazing work Niels

One day, the manufacturers will notice [and appreciate] what you are doing !!

MichaelG.

Fast Ali has delivered my 210 headstock with 85mm bearing holes and 38mm bore spindle on time but with no inner grease seal and dirt and sand everywhere and I am full of joy.

You do not get perfection for 200$

Headstock and spindle fits the old and very well made 920 lathe bed with very minimal modifications.

I have ,as You may remember, made a suitable ,50mm bore,spindle for these headstock that I use in my present 210 lathe for cruelty to scrapsteel.

For a reliable chinese supplier it can be around same manufacturing cost for spindles I think.

920 lathes trades for 300-400£ here and in combination with another 200$ packcage can be unbeatable for cheapskaters.

High resolution pictures.

The Fast Ali 210 headstock fit the 920 bed very well up to now.

You are excused if You do not understand my homegrown german but feel free to ask.

Double clicking the pictures make them very clear.

Strange Liasions

liaisons of course

Edited By Niels Abildgaard on 24/07/2023 16:35:55