2545 forum posts
Here's a post about an adaptor I have just completed. It replicates the D1-3 spindle nose of my lathe as a stand-alone body that can be bolted to a machine table or rotary table, allowing my lathe chucks to be used for work holding elsewhere.
It's been quite an interesting exercise figuring out how to design, machine and assemble it to deliver the functionality I wanted from it. I'm not patient enough to be able to write this up as a magazine article and it's questionable if many people would want to make one anyway. However, I like reading about other people's exploits and ideas, so it seemed only reasonable to post some info on the forum in return.
I have a variety of chucks and fittings for my Colchester Bantam, all of which share the D1-3 Camlock system. The Camlock system uses a combination of a taper and a flat face to locate the chuck concentric and perpendicular to the lathe axis. The D1-3 size also uses 3 eccentric cams to pull the chuck against said face and taper. They act against 3 pins that stick out of the back of the chuck. As I now have 3-jaw, 4-jaw and collet chucks as well as a large faceplate and driver plate, it seemed to me that for some applications it would be very handy to be able to mount any of these either directly onto the milling machine table or onto the face of the rotary table.
2545 forum posts
The Camlock series dimensions are defined in the international standard ISO 702-2. I was able to locate a copy using the combined power and might of the internet and the MEW forum and thus work to the specification rather than having to rely on my own measurements. I started out by procuring a 2" length piece of mild steel of the nearest nominal diameter (4". I set this up carefully in the 4-jaw, faced it off at both ends and then bored it out to 43mm to maximise the work holding capability. Finally, I formed the locating face and taper. At this point I had a spindle nose that fitted the chuck nicely but without any means of holding it on or driving it.
As I would be mounting the adaptor with bolts into the table in use, I drilled and recessed 2 holes at this stage, figuring that I'd find them useful for holding the adaptor during the machining operations. In some ways it would have been more convenient to have had 3 bolts but my rotary table has 4 slots. It was about then that I started to consider what a tricky challenge it would be to position all of the various radial and axial bores within the adaptor body along with the existing 2 bolt holes. It would require some devilish 3D calculations to place them all without clashing.
At this point I installed a 30 day trial demo of Alibre (now called Geomagic Design, baby) and created 3D models for the existing body and the key elements of the D1-3 system, namely the 3 cams and the 3 radial (cam) and 3 axial (pin) bores. I was able to vary the angle between the 2 existing bolt holes and the rest of the components to end up with the best relative positioning by trial and error. With the hindsight now provided I could see that a larger diameter body would have been advisable but I wasn't about to copper up again for another lump of steel. I was unable to avoid one of the bolt head recesses breaking through into one of the cam bores but I figured I'd be able to modify one of the cams and thus make the whole thing workable. I also placed the cam retainer pins on the rear face of the adaptor for simplicity (you can't do this on a lathe nose). I didn't fancy trying to machine the square chuck key holes in the cams, so changed them to external hex heads that I could mill on the rotary table and tighten with a spanner or socket. I also altered the length of the cams to suit the diameter and bore of the existing body. With these 3D CAD systems you can actually spin the cams in their bores and see how the eccentrics move. Groovy.
2545 forum posts
During the machining, I managed to place the 6 bores without the degree of human error and sloppy tolerance that normally betrays my farming genes. The 3-axis DRO, centre finder and rotary table made this task considerably more straightforward than by manual means. I bored the 15mm holes for the pins and the 19mm holes for the cams using the eccentric boring bar holder I described in a post some weeks ago (“simple boring head&rdquo. The accuracy and finish were again of unsurpassed excellence by my standards. I was in uncharted waters here!
The final challenge was the machining of the 3 cams to my own design. I obtained some "Medium Tensile Carbon Steel Bar 1045" (I am living in Canada) which looks reasonably similar to silver steel and got machining. Firstly the eccentric feature, then the retaining slot and the head. Then onto the rotary table (a collet chuck would have been handy here....) for the hex faces, the cylindrical cutout (using the boring bar again) and the machined flat. And finally a tidy up in the lathe and some deburring. Only one slight cockup here on one of them but nothing critical.
2545 forum posts
The blessed thing actually went together like the CAD model and it works like the Real Thing fitted to the lathe. I hardened and tempered the cams using a blow lamp and a bucket of water.
One of the first jobs for the adaptor may be to machine some extra slots in the faceplate. It only has 4 radial slots and I fancy a couple of extra slots to give more options for holding work. I'll mount it on the rotary table and then cut said slots with the aid of the DRO for accurate positioning.
There are several things I’d conclude from this exercise. I certainly wouldn’t have been able to calculate and optimise the correct positioning of the various bores manually. I couldn’t have positioned them correctly at the machining stage without the rotary table and the 3-axis DRO. The 3D CAD (the basic version of Albre) was relatively straightforward to get up to speed with, despite some undocumented features and indifferent technical support. And finally, I would have saved myself a fair bit of time and effort if I’d coughed up for a slightly larger blank to begin with. Overall a fairly satisfying result and one that pleasantly surprised me in terms of accuracy and relative lack of human error.
Hope that was interesting!
|Michael Gilligan||20/11/2013 07:50:34|
10622 forum posts
Yes ... that most certainly was interesting.
A nice piece of design work, and a superb result.
Quite honestly; this is exactly the sort of thing that I would wish to see as an article in MEW. The work is original, and useful; and the write-up is excellent as it stands.
... it leaves me knowing much more, and wanting to investigate further.
Edited By Michael Gilligan on 20/11/2013 07:51:30
|Andrew Evans||20/11/2013 07:53:01|
|154 forum posts|
Interesting posts, I am thinking about making one of these at some point. Main issue I can see for me is that my mill doesn't have as much vertical clearance as yours so I need to check if the adaptor, plus chuck, plus workpiece would leave enough room for the tool.
|Michael Gilligan||20/11/2013 08:02:44|
10622 forum posts
It's a shame about the "accidental smileys" that have crept in to your post, Muzzer ... but we have learned to live with that "feature" of the forum software.
|Andrew Johnston||20/11/2013 09:08:14|
3622 forum posts
Looks pretty damn fine to me, all nicely chamfered too. A real professional job.
|David Colwill||20/11/2013 09:35:49|
|528 forum posts|
I too have wanted such a thing but doubt I will ever end up with such a well executed end result.
|Chris Gunn||20/11/2013 10:15:43|
|234 forum posts|
Muzzer thanks for that, I have advertised for a scrap spindle from a Bantam without success, so I could make something similar from it to transfer chucks from my Bantam to my rotary table and so on. It seems to me you have already done 3/4 of the work required to write it up, so I would encourage you to go a little further so we others can make one. Thanks again, Chris Gunn
3066 forum posts
Great read, and well done
Going to give the download. 196MB exe a try
Edited By Ady1 on 20/11/2013 11:40:42
|John Stevenson||20/11/2013 17:08:56|
5068 forum posts
I have a spare D1-3 spindle out of a CVA toolroom lathe, same as the Monarch 10EE
|853 forum posts|
Muzzer, interesting post, looks very nice. I too need something like this, unfortunately my chucks or lathes don't use the Camlock system so mine would have to be different.
|Graeme W||20/11/2013 17:38:07|
943 forum posts
Don't suppose you've got a spare d1-4 spindle anywhere in the man cave have you?
|John Stevenson||20/11/2013 17:43:43|
5068 forum posts
No sorry, never owned anything with a D1-4 on it.
|226 forum posts|
Muzzer - many thanks for posting this. I would love an article like this for MEW.
As a beginner I have read about folks with myford spindle chucks using them on their lathes, dividing heads, rotary tables, from the lathe to the mill and back. As someone who is new to the hobby I had no choice but to opt for a cheaper lathe than a good condition myford as the prices are eye watering. It has D1-3 and I will be making a version of this. I expect plenty people have D1-4 as well. Slightly off topic but I would like to see more articles that are about making best use of these new chinese or ex industrial type machine tools and this is inline with that.
|Stub Mandrel||20/11/2013 19:05:25|
4302 forum posts
I'm not patient enough to be able to write this up as a magazine article and it's questionable if many people would want to make one anyway
I have to disagree totally with you on both counts, Muzzer! That account would make an excellent article.
|718 forum posts|
Nice work and useful bit of kit. For more fixings to the table I can recommend drilling/tapping holes in place of cutting more tee slots, just add them as required, it is all too easy to overtighten in a tee slot and hey presto a broken table.
|Tony Ray||11/01/2014 18:27:16|
|135 forum posts|
Only just found this great piece of work ! I too would encourage you to write it up for the mag. If not any chance of sharing the CAD files ? A friend & I both need to make one & I have not found one commercially even if I could afford it.
|Andrew Johnston||11/01/2014 22:24:51|
3622 forum posts
My version of Alibre has always run fine under XP.
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
Love Model Engineering? Sign up to our emails for the latest news and special offers!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.