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jackary
01-11-2009, 07:58 AM
Hi All
I have started this new thread now that I have found out how to do it
to avoid overlapping (Hijacking) an existing thread called "Lathe build part 2".
I apologize for any confusion caused.
Over the past few years I have been designing and building a variation
on the Metalmaster. It is made from solid cast iron blocks and
standard mild steel sections to avoid making castings. The essential
difference to the Metalmaster is that the bed remains stationary and
supported at each end and the head and tailstock can be raised or
lowered relative to the bed. A secondary vertical column is
incorporated in the integral tailstock to avoid an unsupported overarm
and tailstock. The machine uses stepper motors to drive each axis. A
separate stepper motor is dedicated to driving the headstock for indexing
the mandrel when required (Stepperhead)
A 430 watt 3 phase inverter controlled motor is mounted on the lower end of the raising column.
Using the polyvee pulleys and inverter give speed range of 15 to 3200 rpm.
The headstock can be moved up or down to change the centre height which can vary between
80 mm to a max of 220mm for large diameters and allow it to be also be used as a milling machine.
The axes can be operated either manually, power driven
by the stepper motors or CNC operated via the lap top computer. I
entered this machine in the Model Engineers Exhibition in 2008 at
Ascot UK where it was awarded a Gold Medal and The Bowyer-Lowe Trophy.
I have written an article which will be printed in the Model Engineers
Workshop soon. I have added a couple of photos under Stepperhead. I
have also added some dodgy videos on utube

http://www.youtube.com/watch?v=Yiug1F8XCME&feature=user
http://www.youtube.com/watch?v=yMxv1jU-R_A&feature=user
http://www.youtube.com/watch?v=FDNTeuojC78
http://www.youtube.com/watch?v=wNxgWhizX54
http://www.youtube.com/watch?v=DMmDCHkff0c&feature=user
http://uk.youtube.com/watch?v=sCsZN8Spbq8
http://www.flickr.com/photos/32647007@N02/sets/72157610446872607/

Regards
Alan

Doc Nickel
01-11-2009, 08:11 AM
That's still amazing. Very nice work.

Doc.

dp
01-11-2009, 08:22 AM
How is it realigned after raising/lowering the head and tail stocks? How do you avoid the "round post mill" curse? :)

The cross slide details are quite interesting, in particular, the diagonal feed screw.

BillH
01-11-2009, 08:22 AM
Very nice!! When you made the tailstock, did you bore it out with the headstock in situation?

jackary
01-11-2009, 08:31 AM
How is it realigned after raising/lowering the head and tail stocks? How do you avoid the "round post mill" curse? :)

The cross slide details are quite interesting, in particular, the diagonal feed screw.

The main column has a triangular gib strip as in the original Metalmaster (see yahoo groups "Metalmaster") The horizontal overarm has a secondary vertical column built in the tailstock. These two vertical columns and the overarm can all be locked together and add up to stiffen and align the whole assembly. The diagonal feed screw rotates a central wormwheel to move the cross slide the full cross slide length.
Regards
Alan

jackary
01-11-2009, 08:36 AM
Very nice!! When you made the tailstock, did you bore it out with the headstock in situation?

The tailstock barrel is a close fit into the mandrel bore. The long tailstock barrel was inserted in the mandrel and tailstock sleeve to align the finished components, then the whole assembly was Loctited together. This was the only way I could think of to get it all aligned.
Regards
Alan

Evan
01-11-2009, 08:49 AM
I have started this new thread now that I have found out how to do it
to avoid overlapping (Hijacking) an existing thread called "Lathe build part 2".
I apologize for any confusion caused.


Thank you Alan. I meant what I said when you first posted it. That is a beauty of a machine. My issues were mainly with John for reasons that go back a while. I in turn apologize to you for any upset this recent nonsense may have caused you.

What size of steppers have you used, particularly on the spindle? Also, what drivers?

jackary
01-11-2009, 09:10 AM
Thank you Alan. I meant what I said when you first posted it. That is a beauty of a machine. My issues were mainly with John for reasons that go back a while. I in turn apologize to you for any upset this recent nonsense may have caused you.

What size of steppers have you used, particularly on the spindle? Also, what drivers?

Evan
No apology needed. I have used Nema size 23 stepper motors, 56mm long on the cross slide and headstock and 76mm long on the saddle drive the motors , drivers and power supply are all from Motion Control. They seem to supply adequate power. I have set them so that they will stall if the axes are overloaded.
They are all geared down about 1:10 by worm drives so they are not as fast as production CNC machines but fast enough for me.
Regards
Alan

Evan
01-11-2009, 09:14 AM
Sorry, but by size I meant the holding torque rating.

Rigger
01-11-2009, 09:29 AM
Alan,
That machine is amazing, in the time I have been on this forum I have never seen anything that looks so purposeful.
Building a machine is one thing but building one to look as well designed as this is another.

Short of Steve's CNC lathe which is also a work of art this has to be the best home build presented here.

I struggle to make bike fittings look as they should, that you won a Gold medal and a trophy speaks for itself.

After the initial misunderstanding I hope you stay around to put a fresh perspective on posts and views.
Contrary to what Evan thinks others are willing to accept alternative views.

Rigger.

jackary
01-11-2009, 09:39 AM
Sorry, but by size I meant the holding torque rating.


FL57STH56-3008B Holding torque 1.24 NM

FL57STH76-2808B Holding torque1.85NM

MSD542 Microstepping Driver (4.2A Peak)

All by Motion Controls

Regards
Alan

Peter.
01-11-2009, 11:55 AM
Superb piece of engineering Alan hopefully one day I'll get to see it in the flesh too.

lazlo
01-11-2009, 12:30 PM
FL57STH56-3008B Holding torque 1.24 NM

FL57STH76-2808B Holding torque1.85NM

For the cretins like myself, who think in Imperial units :) :

1.24 Newton Meters = 176 ounce/inches
1.85 Newton Meters = 262 ounce/inches

Alan, that is a simply gorgeous build! I realized it was inspired by the Metalmaster multimachine when I saw the distinctive horizontal overarm. Does the headstock elevate like a horizontal boring mill?

For those who aren't familiar with the quirky but brilliant "Metalmaster" designed by W. D. Urwick, Tony's got a great page on it here:

http://www.lathes.co.uk/metalmaster/

There's also a Yahoo group of folks dedicated to making modern variants.


How do you avoid the "round post mill" curse?

Urwick received a patent in 1950 for the Triangular Gib Key -- there's a triangular notch milled into the round column, and a triangular gib key wedges into a positive lock:

http://www.lathes.co.uk/metalmaster/page4.html
http://www.lathes.co.uk/metalmaster/img11.gif

jackary
01-11-2009, 01:01 PM
Does the headstock elevate like a horizontal boring mill?

Yes the head ,overarm and tailstock can move up or down relative to the bed
Regards
Alan

Spin Doctor
01-11-2009, 06:02 PM
Very nice piece of work Alan. It certainly looks far more useful than a 3-in-1 combination machine. I wonder just how rigid is the bar bed for the tailstock and what size are the bars. By the way the Flickr link isn't working.

New chips
01-11-2009, 06:36 PM
You say about the steper motors "They are all geared down about 1:10 by worm drives so they are not as fast as production CNC machines but fast enough for me." How did you manage this on the headstock so you could run it by steper or motor from belts on end?

aboard_epsilon
01-11-2009, 06:36 PM
try http://www.flickr.com/photos/32647007@N02/?saved=1

aboard_epsilon
01-11-2009, 06:39 PM
Very nice piece of work Alan. It certainly looks far more useful than a 3-in-1 combination machine. I wonder just how rigid is the bar bed for the tailstock and what size are the bars. By the way the Flickr link isn't working.

It's more rigid than the machine he based it on ..as the bar is supported at both ends

http://farm4.static.flickr.com/3016/3048912316_5dd8d48e2c.jpg?v=0

all the best.markj

lane
01-11-2009, 09:16 PM
I wish I new something about electronics and the computer stuff. I could and would build something like that . The machine work is nothing done plenty of that where I used to work . But the engineers and electricians figured out the rest. I`ll build 2 of them if some one will do the electronics and figure out the computer stuff. Beautiful machine I love it . besides I threw away some of those motor`s the other day because I did not know how to use them.

lazlo
01-11-2009, 09:25 PM
besides I threw away some of those motor`s the other day because I did not know how to use them.

Oh damn -- I sure hope you're kidding, right?

lane
01-11-2009, 09:32 PM
Oh damn -- I sure hope you're kidding, right?

NO they were panasonic brand had about 5 was saving them for you . But you would never come see me. So in the garbage they went Sorry.

doctor demo
01-11-2009, 10:25 PM
I wish I new something about electronics and the computer stuff. I could and would build something like that . The machine work is nothing done plenty of that where I used to work . But the engineers and electricians figured out the rest. I`ll build 2 of them if some one will do the electronics and figure out the computer stuff. Beautiful machine I love it . besides I threw away some of those motor`s the other day because I did not know how to use them.
I'm sure glad that there is another computer/electronics challenged Dinosaur left on the planet besides Me:D . Why are stepper and servo motors rated the way they are...instead of in horse power?
Steve

Michael Hall
01-11-2009, 10:34 PM
I'm sure glad that there is another computer/electronics challenged Dinosaur left on the planet besides Me:D . Why are stepper and servo motors rated the way they are...instead of in horse power?
Steve

This article may help explain why they don't rate steppers and servo's in terms of hp:

http://machinedesign.com/article/the-problems-of-horsepower-ratings-1024

Michael

jackary
01-12-2009, 06:26 AM
You say about the steper motors "They are all geared down about 1:10 by worm drives so they are not as fast as production CNC machines but fast enough for me." How did you manage this on the headstock so you could run it by steper or motor from belts on end?

The mandrel stepper motor geared assembly can be moved up to clear the mandrel spur gear or down to engage the mandrel spur gear with minimum backlash. It is slid down and locked in position when the mesh is right.
The stepper motor drives a worm meshing with a 30 toothed worm then to a 20 toothed spur gear meshing with a 60 toothed mandrel spur gear. The gear assembly also contains a sensor circuit for the mandrel for screwcutting and feeds per rev. The main motor belt is removed for indexing the mandrel.
Regards
Alan

lazlo
01-12-2009, 10:16 AM
This article may help explain why they don't rate steppers and servo's in terms of hp:

http://machinedesign.com/article/the-problems-of-horsepower-ratings-1024

That's a really great article Michael. We should add that to a sticky thread :)

A.K. Boomer
01-12-2009, 11:08 AM
It truly is machinery art, Kudos to you Jackary --- one of the most difficult things in engineering something as complex as this is Is to make it all blend together so that nothing looks as if its an "afterthought".
For all the versatile functions that this thing does you have achieved just that,
Very nice and welcome to the board...

Ken_Shea
01-12-2009, 11:52 AM
I wish I new something about electronics and the computer stuff. I could and would build something like that . .
Alan, just beautiful work, notice the green, that would be green with envy :D


Believe Alan said he was in the same boat at the first, I know I am and it is the hold up on a conversion right now for me, the more I read and try to understand the more confused I get.

Ken

davidfe
04-29-2009, 03:54 PM
Alan,

Do you know what issue of MEW you are featured in?

Absolutely beautiful job.

David

lazlo
04-29-2009, 04:53 PM
I just got this month's issue of Model Engineering Workshop, issue 150 (with the Harrison on the front) and it says that Alan's "Award Winning Lathe" will be featured in next month's issue (i.e., issue 151).

In the 'States, I think we're behind one issue, so the Brits may have Alan's issue already.

John Stevenson
04-29-2009, 04:56 PM
Not quite MEW has speeded up delivery to the US we have had issue 150 for about 2 weeks.

.

jackary
04-29-2009, 05:27 PM
The Editor told me that my write up on Stepperhead will appear in MEW
issues 151, 152, & 153. I think thats June, July, & August. I expect lots of dissent & opinion to make it all worthwhile.
Regards
Alan

davidfe
06-11-2009, 01:36 PM
Alan,

I just recieved the June issue.

The write up and photos are first class.

I look forward to seeing the next two issues.

It is really an outstanding job.

David

lazlo
06-11-2009, 02:39 PM
Ditto. Just got the issue last night, and your lathe is amazing Alan!

jackary
06-12-2009, 05:12 PM
David, Lazlo,
Thank you for your kind comments. I have just received MEW 152 and
I noticed one tiny typo on page 15 two thirds down the first column it states; "The saddle is narrow and is guided by the front bedway" whereas it should read "The saddle is narrow guided by the front bedway". I do not suppose most readers will notice this but it does give a completely different meaning.
Regards
Alan

davidfe
06-13-2009, 10:47 AM
Alan,

Are you using the Stepperhead to produce parts or for projects?

I, for one, would like to see what you use it for.

Also, do you have plans to market the design and drawings?

Regards,

David

Paul Alciatore
06-13-2009, 03:04 PM
Absolutely beautiful work. I also am really green.

kc5ezc
06-13-2009, 08:07 PM
I wish I new something about electronics and the computer stuff. I could and would build something like that . The machine work is nothing done plenty of that where I used to work . But the engineers and electricians figured out the rest. I`ll build 2 of them if some one will do the electronics and figure out the computer stuff. Beautiful machine I love it . besides I threw away some of those motor`s the other day because I did not know how to use them.

Damnation, Lane. Wish I still lived in Bossier. I'm certain we could work something out.

John Burchett
in Byng OK

John Stevenson
06-13-2009, 08:11 PM
Absolutely beautiful work. I also am really green.

In which case you can sell it to Alistair :D

.

jackary
06-14-2009, 07:07 AM
Are you using the Stepperhead to produce parts or for projects?

I, for one, would like to see what you use it for.

Also, do you have plans to market the design and drawings?

David,
I made it to see if I could build a machine that could be useful for the homeshop/model maker with emphasis on flexiblity for as many operations as possible and it turned out better than I expected. I use it for quite a few tasks. I like being able to try out machining ideas on it; half CNC and half manual etc. and have made some bits for ball moulds etc. I already have a bigger lathe and mill which I can use for heavier machining but Stepperhead is very useful for many other jobs. I still have not got a four jaw chuck for it so thats to be done.
I spent most of the winter trying to write a book with drawings (loads of them) on the design and construction of Stepperhead. Its still not finished and I am undecided whether to proceed into the inevitable hassle of marketing it. I was going to see how well the article is received before doing anything else.
Regards
Alan

davidfe
08-09-2009, 11:30 PM
Alan,

Since the last of the article series has come out,
have you proceeded any further with you plans
and potential book?

I would be very interested.

David

jackary
08-11-2009, 05:41 AM
David
Thank you for your interest, I must admit that I have not been doing much to complete the drawings. Apart from your note and two other comments it did not seem that there was much interest. I think most people have seen enough in the MEW article so further description, drawings and construction details is more than they require. I have been working on other projects and this has slipped on to the back burner recently. However I do intend to complete what I started and will let you know when it is done, hopefully in a couple of months time.
Regards
Alan

Al Floyd
08-14-2009, 01:10 PM
Alan
I have enjoyed the MEW articles on the Stepperhead. Please add me to your "interest list" for additional drawings and text for this machine.
Al

S_J_H
08-15-2009, 12:09 PM
Many guys scratch build cnc hobby machines but limit themselves to standard designs. Your machine stands out from the crowd!

I built something that can do similar work to your stepperhead. It is not even close to as elegant and well designed as your machine is though. I consider your "Stepperhead" to be one of the finest looking shop built machines I have ever seen. It is a work of art!!


Here is my cnc do-all / lathe,indexer,horizontal mill,line boring machine. No plans, just made it on the fly so to speak starting off with a super nice and accurate Gilman box way slide.
It has many design flaws I over looked when building it but overall it can do some serious work. It weighs in at around 350lbs.

http://i109.photobucket.com/albums/n48/S_J_H/portablemilldrill009.jpg

Steve

jackary
08-15-2009, 01:14 PM
Steve & Al
Thank you for you nice comments. Steve I think you should also be congratulated on your machine. I have followed it with keen interest and I think we are both trying to make a machine that is as versatile as possible without too many compromises. That is the hard bit, because it is relatively easy to design a machine for specific purposes but as you broaden the range of activities to be catered for it seems there is the risk area. Being aware of design flaws as you put it is the risk you take when doing something creative like your machine. What I was always concerned with what I made was that it would be very jerky when raising the column, headstock & cantilevered overarm. It was at first and I was quite disappointed thinking that it was a design flaw and unsolvable. However I guessed (hoped) that the problem was mis-alignment. I re-bored the auxiliary vertical column bore ensuring that it was exactly vertical and made sure that the new bigger column was vertical when clamped and this solved the problem. But that was always a compromise zone or as they say risk area. Kudos to you Al, the man who never made mistakes made nothing.
All the Best
Alan

davidfe
11-12-2009, 04:32 PM
Alan,

Have you made any progress on your book
or plans to publish Stepperhead design?

Kindest regards,

David
Never Give Up The Garage

tattoomike68
11-12-2009, 05:58 PM
Holy cow! I watched all the videos and am very impressed.

wow, dude you know your stuff. I like it.

Black_Moons
11-12-2009, 06:14 PM
<edit> Nevermind, Figured it out by reading thread

jackary
11-15-2009, 08:00 AM
david fe wrote
Have you made any progress on your book
or plans to publish Stepperhead design?

Hi David,
Apologies for the belated reply, I have been involved doing other projects and have not got any further I am sorry to say. I do intend to finish it,probably in the new year - will keep you posted.
Best Regards
Alan

gda
11-15-2009, 08:42 AM
I'm glad this thread got bumped or I would have missed it.

Truely outstanding work - without being limited to conventional design.

davidfe
03-18-2010, 12:27 PM
So we would not forget.

Please.:D


david fe wrote
Have you made any progress on your book
or plans to publish Stepperhead design?

Hi David,
Apologies for the belated reply, I have been involved doing other projects and have not got any further I am sorry to say. I do intend to finish it,probably in the new year - will keep you posted.
Best Regards
Alan

BillTodd
11-12-2010, 07:42 AM
Jackary,

Have you considered sending Tony at lathes.co.uk pictures of your machine? I'm sure he be more than happy to add it to his homebuilt or universal sections.

Bill

jackary
11-13-2010, 07:19 AM
Bill
I will contact him to see if he is interested.
Alan

rmuell01
11-13-2010, 06:01 PM
To hell with your other projects...... I want the PLANS!:rolleyes:

jackary
12-20-2010, 10:09 AM
To hell with your other projects...... I want the PLANS!

rmuell01,Bill & David fe,
I am sorry to keep you chaps waitng so long but I have just about finished the plans and I intend to send them to MEW
for them to publish. So hopefully they will become available soon. I have also sent some info to Tony Griffiths web page here: http://www.lathes.co.uk/stepperhead/

Alan

jackary
11-01-2011, 06:57 AM
Hi all

My apologies for the delay in replying, it got to the point where an excuse for lack of progress in my reply might have seemed just another delaying ploy, but the Stepperhead book is now complete. I am sorry to say it has taken such a long time to complete 62 detail drawing sheets of about 180 detail parts plus descriptions and suggested construction methods. So if anyone is still interested please send me a private message for more details.

Best Regards
Alan

jackary
03-07-2012, 06:32 AM
In the latest Model Engineer's Workshop magazine No.187 (March 2012), the Editor said that the next issue will see the start of a major new series on building Stepperhead. The articles will include full drawings etc to construct it.
Regards
Alan

George Bulliss
03-07-2012, 09:18 AM
Iíll be looking forward to reading the series; thanks for keeping us posted.

George

Black Forest
03-12-2012, 08:57 AM
I ordered the book and a cd with the drawings. I will let you know what I think when I get the book. I don't really have any plans to actually build the machine. I just thought it would be interesting to read the steps Alan went through to get the machine built.

Who knows maybe I will get inspired and build one.

rmuell01
03-12-2012, 12:47 PM
PM Sent for Stepperhead.

Black Forest
03-15-2012, 09:55 AM
My bood and CD arrived. I ordered it on Monday I think and four days later it came in the mail. From England to Germany that is fast.

The book is great and well written. Even an idiot like me can understand how to build a Stepperhead.

The only complaint I have is Alan didn't sign my book! I chewed on him about that already.

So get out your check books and buy a copy. I think it is well worth the money.

And no Alan did not ask or pay me to write this. If I didn't like it or think it was worth the money I would have also written that here.

Thanks Alan

legendboy
03-15-2012, 11:41 AM
wow not sure how i missed this thread

truly amazing work!

AlphaGeek
03-15-2012, 02:25 PM
Could someone please post a link to a site where the book and plans are available to order? I re-read this thread and did a bunch of Google searches, came up empty. I also checked the www.model-engineer.co.uk site and their associated store, nothing there either.

-AG

jackary
03-15-2012, 04:41 PM
Black Forest thank you for your kind words. I really look forward to your daughter and her friends building a stepperhead, what wonderful teaching program that would be.
Alan

AlphaGeek
03-15-2012, 10:45 PM
If anyone would like to purchase the book (including complete plans) you can PM Alan (aka jackary) and he will sell it to you directly via PayPal.

-AG

Hoplophile
11-17-2017, 12:03 PM
Number me among the worshippers of Stepperhead, but Alan I dare to ask is there anything you might now change based on subsequent experience or input from others?

Is there any change you have considered that might increase the capacity, flexibility or rigidity of the machine? Beyond simply scaling it up that is.

Like many others I think it would be a commercially viable product if built somewhere where quality can be maintained while costs are controlled. Perhaps even in kit form?

Anyway, thank you for sharing it with us!

jackary
11-18-2017, 08:13 AM
Thank you for your kind words Hoplophile. In answer to your enquiry I have to say that after using Stepperhead for many operations there is little I would change. I have a reasonable lathe and milling machine and do most work on these. But for anything small or something that cannot easily be made on those machines Stepperhead excels and is still a pleasure to operate. Things like tapers, splines or curved shapes are easy. The dividing system on the mandrel works like a charm. I just type in the angle required in the laptop the press a button and it rotates the angle and repeat the button push for the next step etc. I was always concerned that the unusual method of moving the cross slide would not be up to scratch after prolonged use, not so, its still as good as new. I also think that the lever locking topslide is so useful that it should be on all small lathes. As to feedback from others I have not really had much. I sold about 40 sets of plans but have not heard if anyone has built one, or any replies on drawing errors, or better methods for construction or design etc.

I did start to design a simplified update, a smaller tabletop version. A wider splashback was going to house the drive motor, inverter, and all the electronics for the axis drives for the stepper motors. It would keep the same camlock design and size with a slightly smaller ER32 mandrel. The headstock, overarm and tailstock vertical movement was simplified with a handwheel operating a vertical feedscrew in the headstock block. The rest of the machine would be much the same only slightly smaller. I have not progressed any further with this as I am busy designing and building a folding bike.

Stepperhead would as you say be good as a self build kit. I could just be a manual lathe if desired with the option of adding stepper drives etc at a later date if required. All the parts are fairly simple machined components, all small enough to be easily handled and transported.

I still think that the homeworkshop person is not well catered for with what is available considering the technology advances in recent years, in fact I think the industry needs to Stepperhead.

Alan

Hoplophile
01-20-2018, 03:36 AM
Many thanks for that reply Alan. I would like to get a copy of your book of plans and drawings if that is still available? Will those somehow be put into the public domain someday?

Would you foresee any problems with scaling up the design by perhaps 25-50% and if that was done, would you change the chuck, camlock & collets used, and if so to what?

If a person did want to add a bit of mass overall, is there anywhere in particular you would suggest that be done? Perhaps more and larger braces between the ways? (I realize this is not actually necessary based on your account here: http://www.lathes.co.uk/stepperhead/index.html but I just have an irrational preference for mass and solidity!;)

In the meantime I should make up an ER32 collet holder similar to yours so I can get some use from this box of ER32s that will never be more than paperweights other wise!

jackary
01-25-2018, 07:13 AM
Hi Hoplophile,
I do not see any major problems with scaling it up at all. You might design the mandrel around say a D3 size camloc and then be able to use existing chucks etc, and you might prefer to mount the motor above the bench, but that is only personal preference. As to adding mass, there is nothing wrong with that, but I would still like to emphasise the advantage of adding the overarm to the headstock and tailstock. The increase in rigidity it provides is hard to quantify but it is there in loads. Be interesting to see the final result. Good Luck

Alan

Hoplophile
01-26-2018, 01:46 PM
Thank you Alan! I can see how the overarm would add the rigidity you mention; it is a brilliant concept I must say. One thing I was wondering about in regard to that is the way the "foot" of the overarm is secured to the bedway. The "hook" of the foot over the back edge of the bedway obviously resists twisting or racking of the overarm and tailstock towards the front side of the lathe, but would there be any advantage to providing a similar feature on the front side of that bedway & foot, so that the same advantage was conferred when for example, machining with the spindle turning in the opposite to the usual direction?

Would there be any benefit to providing a similar clamping feature for the cross-slide base, though I suppose this would require making the cross-slide base a bit longer to accommodate some sort of captive rail with set screws - and an over-ride to prevent the lead screw motor being activated when the lock was engaged!

I did also wonder if anything might be gained by fluting the vertical columns of the head and tailstocks to perhaps reduce friction, provide some chip/dirt clearance?


Hi Hoplophile,
I do not see any major problems with scaling it up at all. You might design the mandrel around say a D3 size camloc and then be able to use existing chucks etc, and you might prefer to mount the motor above the bench, but that is only personal preference. As to adding mass, there is nothing wrong with that, but I would still like to emphasise the advantage of adding the overarm to the headstock and tailstock. The increase in rigidity it provides is hard to quantify but it is there in loads. Be interesting to see the final result. Good Luck

Alan

jackary
01-27-2018, 06:34 AM
Hi Hoplophile,
I do not see any advantages in adding a dovetail groove on the front side of the rear bedway the existing rear dovetail arrangement gives a close guided fit and when it is clamped it is a solid grip. Fluting the vertical columns would be of little gain in my opinion. It will reduce the clamped grip and really serve no useful purpose in my mind.

Cheers

Alan

Hoplophile
01-27-2018, 11:30 AM
Hi Hoplophile,
I do not see any advantages in adding a dovetail groove on the front side of the rear bedway the existing rear dovetail arrangement gives a close guided fit and when it is clamped it is a solid grip. Fluting the vertical columns would be of little gain in my opinion. It will reduce the clamped grip and really serve no useful purpose in my mind.

Cheers

Alan

Thank you again Alan. The way you have combined form and function is a wonderful example of craftsmanship and design. It's an old saying that machines which look "right" invariably are "right" and I hope this one will be in commercial production someday as the combination of manual, powered and CNC functions is exactly what the hobbyist or precision shop requires IMHO. For mobile or remote machine shop services the flexibility and weight are ideal also I think.

The best ideas often take a remarkably long time to be adopted...