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View Full Version : Fixing up a dividing head - the other weekend project!



Mcgyver
05-20-2012, 03:13 PM
Meca Dividing Head.

When I got my BCA mill and Sharp lathe recently, there just happened to be scrap bin there with this Meca Dividing head with a three jaw chuck. What was wrong with it? a broken spacer ring. imo the spacer ring isn't used very often but this is a class dividing head, made in Europe, and deserving of a restore, I took it apart and its in just great shape.

I turned up a replacement ring in cast iron and figured I'd use the head itself to divide the ring. way too much run out on the three jaw. I indicated the dividing head spindle, no measurable runout with a tenths indicator. Then I check the fit of the chuck on the spindle with some blue...seems ok.

Take the back plate off....wow 8 thou run out on the chuck register. Meatheat machinist that made it must of just flipped it around in a three jaw after turning the taper. btw, the mitutoyo mag base (actually a Starrett base with a mitutoyo hydraulic arm) is maybe one of the coolest tools yet acquired - you HAVE to get one! Its just so quick and easy to put the indicator where you want it

http://i785.photobucket.com/albums/yy132/michael01000/Meca%20Dividing%20head/DSC_1306-large.jpg

Since this part is now scrap, I just turned down the chuck register and figure i'd tap out the runout before tightening the bolts - poor man's adjust true!

http://i785.photobucket.com/albums/yy132/michael01000/Meca%20Dividing%20head/DSC_1311-large.jpg

A gear cutter, not rack but next to it proved to be the perfect profile cutter. An easy set up is to indicate the top of the work, then set the cutter at this height...zero and move the table 1/2 work dia - 1/2 cutter thickness.

http://i785.photobucket.com/albums/yy132/michael01000/Meca%20Dividing%20head/DSC_1338-large.jpg

everything is going well - this dividing head is a pleasure to use.

http://i785.photobucket.com/albums/yy132/michael01000/Meca%20Dividing%20head/DSC_1340-large.jpg

Mcgyver
05-20-2012, 03:15 PM
here's the semi finished ring...still have holes to drill. The busted original is underneath the new one

http://i785.photobucket.com/albums/yy132/michael01000/Meca%20Dividing%20head/DSC_1346-large.jpg

holes were done via Hienman transfer screws. If you are not familair these are great tool - as shown in the pic the transfer screw holder also has a hex that is used to turn the screw into the hole to the right height.

http://i785.photobucket.com/albums/yy132/michael01000/Meca%20Dividing%20head/DSC_1345-large.jpg

fits the detent very well - there is no movement possible (of course in use you lock the head each time before cutting)

http://i785.photobucket.com/albums/yy132/michael01000/Meca%20Dividing%20head/DSC_1344-large.jpg

all done! next up is making a back plate and putting a nice little 6" four jaw on it (also out the same scrap bin if you can believe it) I really don't get the common use of three jaws on dividing heads, kind of useless imo for anything but rough work

http://i785.photobucket.com/albums/yy132/michael01000/Meca%20Dividing%20head/DSC_1347-large.jpg

Tamper84
05-20-2012, 04:41 PM
Wish there were some scrap bins like that around here!!! Nice job

uncle pete
05-20-2012, 05:22 PM
Mcgyver,
A nice save and a good object lesson about how much equipment like this gets scrapped from poor reasons. And yeah, 3 jaws used on a dividing head seem about useless for 99.9% of any work that needs a dividing head to begin with. I've yet to understand that one myself. My in comparison to your head, Rather poor quality Vertex came with a 3 jaw. Exactly why I'm not sure. Other than bolt clearance holes on something? It's not really of much use.

Pete

lazlo
05-20-2012, 06:19 PM
When I got my BCA mill and Sharp lathe recently, there just happened to be scrap bin there with this Meca Dividing head with a three jaw chuck. What was wrong with it? a broken spacer ring.

Well that and the main casting is cracked, and someone attempting a brazing repair that cracked it even more ;)

Mcgyver
05-20-2012, 06:21 PM
Well that and the main casting is cracked, and someone attempting a brazing repair that cracked it even more ;)

It is not the main casting, its the cap. I knew someone would have to remark on that lol. thats not a problem, its fine, brazing was properly done probably ages ago. Once upon a time someone tried to diassembley and pried not realizing the cap on that side is pinned to the gear cover

lazlo
05-20-2012, 06:39 PM
It is not the main casting, its the cap.

??? It looks like the main housing is cracked?

http://i164.photobucket.com/albums/u15/rtgeorge_album/dividinghead.jpg

John Stevenson
05-20-2012, 06:47 PM
http://www.stevenson-engineers.co.uk/files/DSC_1306-large.jpg

Nope, split cap.

lazlo
05-20-2012, 06:49 PM
http://www.stevenson-engineers.co.uk/files/DSC_1306-large.jpg

I'm talking about the braze, which looks like it's on the main housing, not the split clamp that's clearly visible on both sides.

John Stevenson
05-20-2012, 06:55 PM
Follow it round to the back and you will see the retaining bolt.This is a half cap that bolts the main casting with the worm in it down to the base casting. two straps / caps, one each side

willmac
05-20-2012, 07:00 PM
It is only the cap. I have one of these and as McGyver has said, it is not immediately obvious how it comes apart, so I could see how a real ignorant gorilla could break it this way. The edge of the cap is not really visible in the photo, but is there.

A bit of trivia that might be of use to Mcgyver or someone else. The dividing plates for a Bison 10" rotary table fit this dividing head perfectly. maybe there is or was some connection between the products at some stage?

daryl bane
05-21-2012, 12:26 AM
I don't care about the head :), but you're photography is frigging gorgeous. Holy crap, what camera are you using?

Mcgyver
05-21-2012, 09:31 AM
thanks daryl, it's a standard Nikon digital SLR, D80 I think. technique is very basic but seems to work for me; never use a flash, use a tripod and most of the time strive maximum depth of field by using small aperture (high f stop) and long exposure. Some would be 30 seconds long for example. A good sunny day creates a bit more contrast, i.e. you can it to hit the highlights.

willmac, that's good know. I think I'm going to keep this one so will want to start collecting them. I'd thought a bunch of plates would be a good cnc project but they should probably be hardened so it gets to be a pita making them.

Also got the tail stock for it so its fairly complete. I don't have the drive thing, you know, the piece that goes on the spindle to catch the dog? if you've got one, any chance of a picture? thanks

TGTool
05-21-2012, 09:47 AM
In the dividing plate business, don't forget that John Stevenson is set up to supply those. If you're already equippped with the CNC capabilities then he's probably no advantage.

willmac
05-21-2012, 11:14 AM
willmac, that's good know. I think I'm going to keep this one so will want to start collecting them. I'd thought a bunch of plates would be a good cnc project but they should probably be hardened so it gets to be a pita making them.

Also got the tail stock for it so its fairly complete. I don't have the drive thing, you know, the piece that goes on the spindle to catch the dog? if you've got one, any chance of a picture? thanks

I don't have the driver either so unfortunately can't help, but they shouldn't be too too difficult to make. I have a large 4 jaw chuck in fair condition which came with mine. The down side is that the total assembly needs a crane to get it on my mill.

I got one single plate with mine. It is double sided and if it would help I will take a photo of it or list out the hole numbers for you. I think there should have been two plates (or more?) originally, which is how I found out about the interchangeability with the 10" Bison plates.

One day I will get around to making a stepper indexer, that can interchange between dividing head and rotary table. Much better than working with plates.

Mcgyver
10-15-2012, 06:37 PM
thanks guys....the cnc mill is a wiring job away for operation (I hope) so will try making some plates

just to finish off the dumpster dive dividing head......the crank handle was missing. Made a new post of steel and a black delrin handle...the stuff machines so nicely its easy to get pro looking results. I used the dividing head and a ball endmill to produce the flutes

http://i20.photobucket.com/albums/b201/michael0100/Meca%20dividing%20head/DSC_3863-large.jpg

http://i20.photobucket.com/albums/b201/michael0100/Meca%20dividing%20head/DSC_3877-large.jpg

The tailstock handwheel was a mess...knocked out he taper pin and scrapped it. Use my cut knurling tool to make a new one

http://i20.photobucket.com/albums/b201/michael0100/Meca%20dividing%20head/DSC_4347-large.jpg

Mcgyver
10-15-2012, 06:38 PM
turned a new cover plug ....metric threads...but no problem for the DSG :) you just about need a pilots license to thread on it but once figure out all the levers it'll do anything

http://i20.photobucket.com/albums/b201/michael0100/Meca%20dividing%20head/DSC_4328-large.jpg

This little pin for use as a spacer was too wobbly in the hole, so i made a new one
http://i20.photobucket.com/albums/b201/michael0100/Meca%20dividing%20head/DSC_3885-large.jpg

all cleaned and painted. I could have done more sanding etc, but wanted to get it into service.

http://i20.photobucket.com/albums/b201/michael0100/Meca%20dividing%20head/DSC_3883-large.jpg

Mcgyver
10-15-2012, 06:39 PM
and there it is done...not bad for a dumpster dive!

http://i20.photobucket.com/albums/b201/michael0100/Meca%20dividing%20head/DSC_4353-large.jpg

and helping make chips. (making a boring bar tool post for the DSG)

http://i20.photobucket.com/albums/b201/michael0100/Meca%20dividing%20head/DSC_4546-large.jpg

sasquatch
10-15-2012, 06:44 PM
Nice work and good save of a dumpster find!! Very nice!!

millwrong
10-15-2012, 07:26 PM
"In the dividing plate business, don't forget that John Stevenson is set up to supply those" Don't mean to hijack this thread, but is this true?

jkilroy
10-15-2012, 08:33 PM
Very nice sized dividing head, I would love one about that size. My KT head is just a tad large for easy handling.

customcutter
10-15-2012, 10:23 PM
Nice work. Wish my weekends were that long.:D

Ken

customcutter
10-15-2012, 10:25 PM
"In the dividing plate business, don't forget that John Stevenson is set up to supply those" Don't mean to hijack this thread, but is this true?

IIRC, I beleive it is true. Seems I recall reading that somewhere.

Mcgyver
10-16-2012, 08:18 AM
Nice work. Wish my weekends were that long.:D


lol, yeah that was a long one.....most, except for the plastic handle, was done the first weekend, I just waited until i had some pics of it in action before posting the last bit