Boxford Lathe Big Bore Conversion

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Niels Abildgaard on 15/08/2017 11:20:48:

There was another gentleman here from UK that had a spare headstock that he was willing to sell.

.

Thanks for the mention, Niels

Brian has been in contact … and I think we have a plan.

MichaelG.

[SillyOldDufferModerator @sillyoldduffer]

Welcome back Michael!!!!

[JasonBModerator @jasonb]

The 280 headstock is 180mm long though there is sufficient 45mm dia on the spindle that a 190mm long head casting would not cause issues.

Quick sketch of spindle below, click to make larger. Bore is 26mm to clear 1" stock, MT4 taper, Flange chuck mount. At the far end there is a section of 40mm dia which has a key slot and this takes the gear for feeds and the two step pully. Adjusting nut on the M39 thread. Spacer on the bit of 45dia that sticks out the head so that when nut is tightened everything pushes against the bearing. Sizes are as good as I can get without removing the spindle.

Edited By JasonB on 15/08/2017 12:26:33

[Niels AbildgaardParticipant @nielsabildgaard33719]

Thank You Jason

How do You like the flanged chuck connection or are You dreaming camlock etc all the time?

[JasonBModerator @jasonb]

It is not ideal but I am used to it having had an Emcomat 8.6 for 20 years before the 280 which used flange mount although that did benifit from the short din taper rather than parallel. Luckily I have slim fingers.

It may be possible to track down a spindle from someone other than Warco that uses the keyhole ring method as some are available with that option and a few have been seen with D1-3

I'll keep dreaming of that late model Colchester bantam 2000 with its 13" swing, 40" between ctrs and a gap bed.

[HopperParticipant @hopper]

And here's a Hercus 260 spindle for A$280 plus shipping. ID is 1-1/16". Not sure what size bearings it takes.

**LINK**

[Brian MossParticipant @brianmoss64697]

My preference if possible is to convert to 290 specification (i.e. 38mm bore), but the above amazing information would be ideal for someone wanting a conversion to 26mm.

Many thanks to everyone for the information supplied so far.

Brian.

[Neil WyattModerator @neilwyatt]

Please, Brian or Niels, if you decide to do this keep photos and notes, as it would be a very useful and interesting article for MEW.

Actually, a short article on camlock chuck mountings would be good as well, if anyone wants to to have ago! They only ever get mentioned in passing and for anyone who hasn't actually used one they are a bit of a mystery.

Neil

[Brian MossParticipant @brianmoss64697]

Niels,

I have sent you a PM,

Brian

[Brian MossParticipant @brianmoss64697]

I have now obtained a spare Boxford headstock casting (many thanks MichaelG) in order to pursue the feasability of fitting a 290 spindle with a 38mm bore. Can anyone provide dimensions of a 290 spindle as JasonB has done above for the 280?

Niels: does your offer still stand regarding your spindle and bearings as per your earlier post? Obviously now I would not need your very heavy headstock casting. Or initially could you let me have dimensions of them?

Many thanks,

Brian.

[Nick_GParticipant @nick_g]

.

Boxford list as a spare the spindle for their X10 range of machines. These have a 35mm bore and a D1-3 camlock capability. Will cost a good few coins though.!

Nick

[Brian MossParticipant @brianmoss64697]

Nick,

I daren't ask! But thanks for the information though,

Brian

[Thor 🇳🇴Participant @thor]

Hi Brian,

I don't have the dimensions of the 290 spindle, but the manual says this for spindle bearing:

2007109E which should have I.D. 45mm, O.D. 75mm and W 20mm

I hope this may be of help.

Thor

Edited By Thor on 18/08/2017 13:07:03

[Niels AbildgaardParticipant @nielsabildgaard33719]

Posted by Nick_G on 18/08/2017 11:37:53:

.

Boxford list as a spare the spindle for their X10 range of machines. These have a 35mm bore and a D1-3 camlock capability. Will cost a good few coins though.!

Nick

Spindle bearing outher 96.83 and 90

Standard Box A headstock 76.2 and 72

How to bore?

[JasonBModerator @jasonb]

Posted by Thor on 18/08/2017 13:06:14:

Hi Brian,

I don't have the dimensions of the 290 spindle, but the manual says this for spindle bearing:

2007109E which should have I.D. 45mm, O.D. 75mm and W 20mm

That is interesting as it would imply that the 290 with its 38mm spindle bore has a rather thin spindle wall compared to the 280 with its 26mm bore as they use the same bearings

However if that were the case then why would Neils have had to bore things out to fit larger bearings?? Though looking at his linked photos the headstock end bearing appears to be larger and I could not see that bearing spec in a large bore parts list I just checked

Edited By JasonB on 18/08/2017 13:45:14

[Thor 🇳🇴Participant @thor]

Hi Jason,

You are (as always) right, my manual clearly gives the wrong size of the bearing. I have just been in the workshop and measured the rear end of the spindle, an I.D. 45mm bearing wouldn't fit. Should of course have done that before posting.

I assume the diameter is 47mm, I took the photo using one hand on the caliper, the other on the camera, sorry for not being able to line up properly.

 In the parts list you linked to bearing 14 is 2007109E (page 30 in the PDF).

Thor

Edited By Thor on 18/08/2017 14:28:38

[Niels AbildgaardParticipant @nielsabildgaard33719]

The 290 spindle on photo has 38 mm bore and bearings are 95/60 and 90/55

**LINK**

I will try and exchange it for a 280 spindle

[Brian MossParticipant @brianmoss64697]

Hi Niels,

Very many thanks for this excellent information. From your photo I have estimated the lengths of each of the 7 sections of the spindle as follows starting from the threaded end: 80mm (including thread), 20mm, 50mm, 80mm, 60mm, 25mm, and 20mm.

Could you please confirm that these figures are correct, and if wrong could you give the correct lengths?

Finally , what is the diameter of the flange for fitting a chuck?

Regards,

Brian.

[Niels AbildgaardParticipant @nielsabildgaard33719]

Hello Brian

 

Starting from chuck end. Diameter and length

 

70/14  123/16,5  70/24  60/59,5  57/73  55/45,6   52/21  48/50

Thread M48 pitch1,5 mm/24,5.

Do You have an idea how to line bore precisely?

Kind regards

Niels

 

 

Edited By Niels Abildgaard on 18/08/2017 18:44:11

Edited By Niels Abildgaard on 18/08/2017 18:46:28

[Brian MossParticipant @brianmoss64697]

Hi Niels,

Many thanks for the above; now the real head scratching begins!

My idea would be to line bore the spare headstock on the bed of a similar Boxford lathe. It sounds straight forward (famous last words) but I think it could be done accurately with care.

Kind regards, and thanks again,

Brian.

[Nick_GParticipant @nick_g]

Posted by Brian Moss on 18/08/2017 20:12:03:

Hi Niels,

Many thanks for the above; now the real head scratching begins!

My idea would be to line bore the spare headstock on the bed of a similar Boxford lathe. It sounds straight forward (famous last words) but I think it could be done accurately with care.

Kind regards, and thanks again,

Brian.

.

Hi Brian,

Do you mean in a similar way to this but with the headstock and not as in this example the tailstock.?

[Niels AbildgaardParticipant @nielsabildgaard33719]

Posted by Brian Moss on 18/08/2017 20:12:03:

Hi Niels,

Many thanks for the above; now the real head scratching begins!

My idea would be to line bore the spare headstock on the bed of a similar Boxford lathe. It sounds straight forward (famous last words) but I think it could be done accurately with care.

Kind regards, and thanks again,

Brian.

 

 

Hello Brian

 

Good luck with boring and give us many clear photos.

It is a lot of bother to find a container for sending You the spindle and I cannot do it rigth now.

Contact me when You have succeded line boring and I will look for a suitable postage box in the meantime.

 

Kind regards

Niels

Edited By Niels Abildgaard on 19/08/2017 08:43:08

Edited By Niels Abildgaard on 19/08/2017 09:03:47

[Brian MossParticipant @brianmoss64697]

Hi Nick_G,

That's great to see! It's amazing what you can find on YouTube,

Brian.

[Brian MossParticipant @brianmoss64697]

Hi Niels,

That's fine, and thanks for wishing me luck!

I have sent you a PM with my email address so that we can keep in touch,

Regards,

Brian.

[Niels AbildgaardParticipant @nielsabildgaard33719]

Posted by JasonB on 15/08/2017 12:21:26:

The 280 headstock is 180mm long though there is sufficient 45mm dia on the spindle that a 190mm long head casting would not cause issues.

Quick sketch of spindle below, click to make larger. Bore is 26mm to clear 1" stock, MT4 taper, Flange chuck mount. At the far end there is a section of 40mm dia which has a key slot and this takes the gear for feeds and the two step pully. Adjusting nut on the M39 thread. Spacer on the bit of 45dia that sticks out the head so that when nut is tightened everything pushes against the bearing. Sizes are as good as I can get without removing the spindle.

Edited By JasonB on 15/08/2017 12:26:33

Jasons idea is very smart.No headstock modification and much bigger spindle bore and /or bending stiffnes .

Let us calculate .

Existing set up is lower part of picture and outher profile of spindle is a short piece of 3.81cm and rest is 3.5cm diameter and spindle bore is 2.05cm.

For a first aproximation let us say 3,6cm outside with a hole of 2.05

Bending stiffness is a fourth power thing and is proportional to 3.6**4 – 2.05**4 =168-18=150(more or less)

The new spindle is 45 mm outside and i want to calculate how big bore for same bending stiffnes

Equation becomes 4.5**4-X**4 = 150 giving a bore of 4.0cm

Double bending stiffnes is 4.5**-X**4= 300 allowing a bore of 3.2 cm

If we do not modify the chineese spindle that is 2.6 cm inside we get a stifnesvalue of

4.5**4-2.6**4=365 or roughly 2.4 times the boxford spindle value.

 

 

 

 

 

http://[img]http://i.imgur.com/fX55Bjm.jpg%5B/img%5D

Edited By Niels Abildgaard on 29/08/2017 20:01:31

[Author]

Posts