lathe index plate

[Simon MarksParticipant @simonmarks43050]

Good Morning all,

I am in the process of getting together the tooling required to tackle the seminal “Quorn”. One of the things I need to be able to do is accurately index my lathe to enable the scribing of the hand wheel dials. I am looking for a simple design that clamps into the bore of my spindle.

I have tried searching the forum and have not been able to find anything that meets my requirements. I am sure this has been done to death so if anyone can point me in the right direction I would be most grateful.

Simon

 

[martin haysomParticipant @martinhaysom48469]

have a look at the Quorn group website lots of help/ advice there. i do this by fixing my rotary table to the headstock. best of luck with your build

[BazyleParticipant @bazyle]

You can make a quick bore clamp from the type of wall bolt fixing that pulls a wedge up between two jaws with some plastic wrapped round for protection.
Print a linear scale of the required number of ticks and wrap it around the circumference of a ply disc turned to size.

Loads of references to dividing in the forum you just need to try all sorts of search words.

[bernard towersParticipant @bernardtowers37738]

You could do this

[Simon MarksParticipant @simonmarks43050]

Thanks for the input.

Love the Myford solution – its a work of art- but given the amount of use it will get it is probably a bit OTT for my purposes.

I did have in mind something along the lines that Bazyle suggested but with a little more sophistication. I have an old spin indexer that I could sacrifice for the purpose but really feel I should put the effort in and make something from scratch.

I was hoping that one of the clever people on here had a nice simple solution they would be prepared to share. I want to start the Quorn early in the new year and I already have several Hemingway projects to finish first so I don’t want anything too complicated.

[ChrisLHParticipant @chrislh]

If you have a lathe with a set of change gears, one can usually set up a train of gears (connected to the lathe spindle only) so that the final gear of the train can be used as the “index”. A simple small plunger is arranged to engage between the teeth of the “index” to provide the desired number of divisions. The work at the business end of the spindle is marked with a suitable tool held in the toolpost and worked back and forth. Nothing original of course and learned by me many years ago from L H Spareys’ book “The Amateurs Lathe” which is a good read and still available and relevant after 75 years !

[bernard towersParticipant @bernardtowers37738]

Bazyles post of the linear strip has been used for X number of years and is hard to beat for results and effort to make if you dont think you will do this sort of job again.

[John PurdyParticipant @johnpurdy78347]

Simon

Here’s the system I have used to index the lathe to scribe the graduations on quite a few various dials ( Quorn, boring head, lathe cross and top slide, rotary table, etc …). By setting up the change wheels any divisions can by indexed. The picture below is set for 50 divisions. The cord wrapped around the chuck goes up over a pulley screwed to the bottom of the shelf on the wall behind the lathe and is connected to the old sash weight visible behind the chuck to eliminate backlash in the gear(s).

John

[Chris CrewParticipant @chriscrew66644]

The Quorn is yet another one of my unfinished symphonies but I accepted at the time of its commencement that it would test, almost to destruction, the extent of my very limited toolmaking and workshop skills. In the years preceding buying the castings I discovered the pleasure making and using well-designed attachments for the Myford lathe, notably those of Jack Radford. His head-stock dividing attachment (only suitable for the Super 7 & ML 7R), his graduating device and his spherical turning tool all proved their worth when making Quorn components. GHT enhanced and ‘corrected’ some of Radford’s ‘faults’, there is an error in his worm data for the headstock attachment for example. I think your time would be well-spent making some of these type of attachments, which will then be available to make your life easier for all future projects, before commencing your Quorn instead of looking for ‘quick-fixes’, although I understand the enthusiasm for wanting to ‘get on with the job’. For me, it was all good toolmaking practice and I learnt a lot in the process the results of which have shown up, hopefully, in the Quorn components I have thus far made.

[Simon MarksParticipant @simonmarks43050]

Again many thanks for all the feedback and in particular Chris for the words of warning. I think most of us start with lots of enthusiasm and good intent but as the project progresses other distractions take over. Especially when a faced with a tricky part.

My biggest issue with the change gear route is the need to do 360 increments. although very simple in theory I foresee plenty of  room for error. The biggest change gear I have that would work is 72 tooth so I would need to clock it’s position to do all the intermediary increments between the 5’s and 10’s.

John love the way you dealt with the backlash I would not have thought of that and would probably have tried to over complicate things with some sort of spring arrangement.

Anyway many thanks for your comments. I will ponder my options while finishing off the Graduation, Knurling and spherical turning kits I am in the process of making.

Simon

 

[John HinkleyParticipant @johnhinkley26699]

Simon,

As far as I can see, you haven’t said which lathe you have, but if it’s of any use or gives you food for thoiught, I offer my take on it.

It’s was a progression from my simple indexing feature in MEW some while ago, further explored in my low-profile rotary table.  It consists of an annular ring which slips over the chuck and is secured thereto. Another ring, drilled at 10° intervals around the outside is overlayed by a segment plate, drilled at 11° intervals.  More complicated than is is, actually.  A picture paints a thousand words and a video or two even more, so …..

It used to be in an album, now drifting in the multiverse, but a video to watch is here on YouTube.

It effectively gives you the equivalent of 360 holes drilled radially in the chuck backplate, indexed by a pin of some sort.

John

P.S.  I no longer possess the lathe, this accessory or the 3D router it was made on, or I would offer to make one for you.

[BazyleParticipant @bazyle]

You mentioned that you have a spindex so perhaps the index plate can be taken off that. Otherwise if you know someone with a 3D printer there is a program on Thngiverse that enables you to create prints of annular rings of any size with any number of holes that could be used to make the parts shown by John above.

thing:1908993

https://www.thingiverse.com/thing:1908993

[Simon MarksParticipant @simonmarks43050]

John that is very much what I had in mind but fitted to the spindle from the other end. I have a Warco 290V so this would be relatively simple as it has plenty of room in this area. My problem is accurately drilling all the required holes. A CNC router or mill would be the perfect solution but I don’t possess one unfortunately. I might try doing it on the rotary table but I would have to be ultra careful when moving from one location to the next.

Bazyle if both parts of the spin indexer were able to be removed I would have gone with this route but one side is integral to the main body casting. Sadly in this day and age I dont know anyone who is into 3D printing. Again it is something I would love to own but I am so tight for space I have had to make the hard decision that CNC and 3D printing are not a realistic option.

[John PurdyParticipant @johnpurdy78347]

Simon

To do 360 degree graduations, use a compound gear train.  What I used for the Quorn and the rotary table was 75 x 25/70 x35/60 where 75 is on the tumbler, 25/70 on the first stud, 35/60 on the second stud, with 60 being the count wheel, each tooth being 1 degree. Any gear set up that will give a 2:1 and 3:1 reduction driving the 60 tooth count wheel will work.

In my second picture in my post above note the belt hanging on the lathe belt tension lever behind the chuck – that’s the primary drive belt removed. The last thing you want is the lathe to be inadvertently turned on when it is in this set up!!!

John

[Simon MarksParticipant @simonmarks43050]

Good afternoon,

For those who might be interested and anyone who might want a solution to the same problem I thought I would update this thread and show the solution I came up with. This is for a Warco 290V.

As I stated in an earlier message I have “borrowed” the spin indexer principle with 36 evenly spaced  holes in the inner plate and 10 holes spaced at 11 degrees on the outer.

The nut in the Centre pulls on a tapered plug which locks the inner disc to the chucks rotation. The outer disc is fixed to the lathe body. This will give me the 360 graduations I need but will also give any number which is a factor of 360 so might prove useful for another project. These were all drilled using a bit of schoolboy maths and my DRO. Probably not the most accurate solution but after I reamed them through it seems be sufficient for my purposes.

All I have left is to number the two plates, Anodize the parts and Loctite the outer disc in place.

Regards

Simon

ps Sorry if this is a bit simple for most of you but I thought it might help another beginner facing the same problem as I was.

[Michael GilliganParticipant @michaelgilligan61133]

That looks very tidy, Simon

… nicely done !

MichaelG.

[Author]

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