Elliot 3 1/2 dividing head.

Sorry Mark,

These all came off bigger heads and are far bigger on the gears.

The gear in this pic is well over 2" in diameter.

If you want new gears then for just 3 off HPC is probably the best bet but you do realise you only need these gears for spiral milling or compound dividing.

Normal straight dividing just using the plates doesn't use these gears.

Edited By John Stevenson on 09/12/2016 21:41:34

You might need them if you do any "Spiral Slotting"

This is part of the clutch on my Pollitt & Wigzell barring engine.

Phil

10 minutes with a 4th axis and cnc

This thread is showing some interesting 'innards' of a common variety of dividing head which I have not seen elsewhere on the 'net. Anyone know more about the split worm-wheel? It seems odd that one screw is slotted (forcing screw perhaps?) and the square headed ones are not done up to their shoulder, nor are they evenly spaced.

John , it doesnt matter ,i `ll try cutting the gears once i get the broken bush sorted out.

Bazyle, i dont understand the split worm wheel either ,id never heard of one until someone mentioned it, i also dont want to fiddle with it either ,in case i alter the adjustment.

The manual describes 3 screws ,even though they are 5 in the worm wheel. One described as just a screw, another a worm screw and one an eccentric screw.

I think its supposed to do something like this.

Edited By mark smith 20 on 10/12/2016 00:30:07

Edited By mark smith 20 on 10/12/2016 00:32:36

Ive decided instead of making the whole bush with flange ,that it may be easier to make the flange with a shorter round section and fix it somehow to the original main bushing body. (as the bushing is totally intact minus the broken off flange.)

Anyone have an idea what would be the best way of securing this ?

If i turned down the outside end of the bush to about half thickness and made the flange with a sleeve bored out to mate with the original bush. I could super glue it and ten maybe blind pin it .

Edited By mark smith 20 on 18/12/2016 11:14:33

Edited By mark smith 20 on 18/12/2016 11:14:58

Edited By mark smith 20 on 18/12/2016 11:21:48

Mark,

Loctite 638 would be my choice

MichaelG.

Hi Michael , thanks and would you use a few  pins as well around the circumference of the joint??

Edited By mark smith 20 on 18/12/2016 11:29:34

.

Personally, no ... 'though I suspect that some others might.

I have been using 638, occasionally, for about 30 years; and have never had a joint of this style fail.

MichaelG.

Thanks Michael . i dont really see much use for pins as its not moving and is just really a bush for the worm shaft.

Hi Michael ,

Does that mean that, in practice, the shelf life of 638 is 30 years?

Best regards,

Swarf, Mostly!

.

I have actually used it at work and at home during that time; but the large bottle currently in use is about 30 years old ... So, in my experience YES and probably longer.

I have mentioned this before, but it's worth repeating: When I asked Loctite [in the pre-Henkel days] about 'shelf life', the answer was basically "Shelf Life !?! ... is it still liquid? ... if so, it's fine to use".

My experience confirms this to be a reasonable assessment.

MichaelG.

Another point might be to consider whether in its working position it is I contact with the hole it fits in all the way along and whether it needs to be. If it is in a long close fitting hole perhaps the centre of the bush can be relieved and if it is just fitting in the casting wall perhaps the end can be relieved. Either will reduce difficulty of insertion and removal in the future.

Bazyle , it is a very tight fitting bush, but as you say i dont really see why it needs so much contact area in the casting (along its full length). It doesnt spin or anything,its just basically a guide for the worm shaft.

One thing i wondered is why all those thrust washers are pinned to each other and the bushing and outside locking nut ,with oil grooves on one side of each ?? Anyone suggest a reason as they are tiny and fiddly.

In fact im totally confused by them, i mean if they are all pinned to each other and the bushing which doesnt move ,how is the locking nut supposed to turn/tighten  as it also has the two pin holes. The pins arent mentioned in the parts list neither is one of the thrust /oil washers. I only have 3 washers???

Edited By mark smith 20 on 18/12/2016 18:38:10

Edited By mark smith 20 on 18/12/2016 18:54:19

No-one have any thoughts about these pins??

Simply pinned so they do not move at those interfaces. Movement between parts is then restricted to the surfaces/areas where lubrication is afforded.

Edited By not done it yet on 19/12/2016 07:08:52

This is my take on it, others may disagree.

It may have been modified by a previous owner or even the shop floor not understanding how it should work. Some washers may be to fill in space. The bearing interfaces are a steel washer against each other, not as you might expect against the cast iron. This is because the CI would wear more quickly and introduce slop. You can see this problem in old lathe cross slide screws bearing against the end plate. (Myford /Drummond)
So 16 needs to be pinned to the shaft, 17 pinned to the bush with the oil groove between. On the outside one is pinned to the bush and one to the nut. The nuts might be pinned together after setting.

Not done yet, makes sense i suppose but still puzzling hard to explain i suppose just from the photos.

Bazyle , interesting idea which thinking about it, it may be right idea, i`ll have to make sure i get the pins in the correct places.

Well i repaired the shattered piece of the bush as described above using en3 steel ,only stuff wide enough i had lying around.

Ive glued

the joint with loctite 638, and ill see what its like when dry. The diameter of the round repair bit is just a touch under the diameter of the original piece ,to make it easier to get out again if needs be. Though its still a tight fit with the section of the original piece .

Just have to find the other screw that fell on the floor and vanished

Edited By mark smith 20 on 21/12/2016 15:10:32

Edited By mark smith 20 on 21/12/2016 15:13:39

Edited By mark smith 20 on 21/12/2016 15:14:51

Edited By mark smith 20 on 21/12/2016 15:15:09

Edited By mark smith 20 on 21/12/2016 15:15:47

Looks good, so far, Mark

MichaelG.