Victoria 10 inch Dividing Head Refurbishment

Wedg1e · Mar 27, 2023

Largely as an exercise I had a crack at making a spare dividing plate for my (IXL-style) div head.
Cut a disc out of some 6mm aluminium plate, bored it and centred on the rotary table.
The table is graduated down to something like 5 minutes of arc so I knocked up a spreadsheet that calculated what hole circles I could get working to the nearest graduation and set to with the Perrin pedestal, using a cente drill to spot the holes.
It worked, in the sense that I got complete circles, and as Agro says, any slight positioning error is reduced to 1/40th by the head's worm ratio.
Never found a use for the bloody thing, but I'm sure it'll be added value when my descendants sell it all off.

Agroshield · Mar 27, 2023

Wedg1e said:
...any slight positioning error is reduced to 1/40th by the head's worm ratio.

And if you were really fussy, the first thing you use the hand-drilled plate for is to make another 'identical' one on the dividing head. Then when you use that, the original error is reduced to 1/1600.

RobCox · Mar 30, 2023

So, the next instalment of this saga. For the past week work on this has consisted of primer, filler, primer, filler, primer, paint and more paint. This was the state of the parts on Tuesday:

The last part outstanding to clean up was the chuck. It all came apart without any fuss as soon as I'd worked out how to disassemble it. Separating the backplate from the chuck body revealed this:

A day spent up to my ears in white spirit using copious amounts of elbow grease with a wire brush, a scotchbrite pad, scrapers of various sizes and finally metal polish yielded this collection of cleaned up parts:

So on to the reassembly. The label reveals it's a Griptru type, so it can be adjusted:

There are three tapered bolts that pull the front of the body around on the rear casting:

So in with the scroll and the pinions and fit the retaining pins:

then the back is fitted in place (I forgot to put some witness marks on to align it as it came off :ashamed:

but it didn't matter as there were enough dings to work out which was it went before) and lightly snugged:

The three tapered pins then go in the side which locks it all together and allows adjustability:

This one's only part way in. Then, to align it, I put the backplate (which has a nice close fitting register) into my 3 jaw on the lathe. I ended up with a 1 thou shim under one jaw to get the register lip to run true:

The "doubleboost" tool on the lower right had been used to get the face flat and true. Runout was <0.01mm. I then bolted the chuck to the backplate, clamped a length of silver steel in the jaws and tweaked the adjustment screws to get it to run withing 0.01mm. Then the chuck was removed from the backplate and the three bolts holding the chuck body together were tightened properly.

RobCox · Mar 30, 2023

So to the reassembly of the behemoth. It fought every step of the way! Anyway, below is an edited reassembly sequence leaving out the wrong turns. I've no maintenance manual or anything (if one ever existed!) so had to work it out as I went.

Step 1, take the worm assembly and put it together. These are the component parts:

They are laid out in the order they go on the worm and housing. Before the gear is fitted to the end two countersunk screws secure the bearing block onto the housing:

First problem. Everything ran smooth until these were tightened hard, so there is some misalignment somewhere. I nipped them up so the shaft still ran freely. Then the gear goes on and the thrust bearing preload is adjusted to minimise backlash in the worm assembly:

There's a copper disc under the grubscrew to prevent the threads being mangled. This then goes in the main body of the dividing head:

But don't push it home yet, otherwise this stub shaft won't fit:

So this shaft has to be nestled between the gear and bearing block and the whole lot pushed in (or the gear could be fitted later and the worm backlash adjusted in situ:

The stub shaft houses this intermediate gear which is carried on two coaxial eccentrics. I didn't fit it yet as the gear meshing adjustment requires the worm to be correctly meshed with the worm wheel, which needs the spindle fitting:

The worm adjustment lever is then fitted on the other side of the head. First the two spacers:

Then the lever. I missed painting this initially, which delayed reassembly as it's needed to hold the worm clear of the wormwheel for the spindle to go in:

The securing nut and locking nut are fitted and the worm moved away from it's engaged position:

RobCox · Mar 30, 2023

And so to the spindle. Assembly of this into the body took hours. First, deburring anything that didn't fit smoothly - some burrs caused by me during dismantling :ashamed:

. The worm wheel key was so tight it wouldn't even fit - something like 2 thou oversized for a 1/2" key! I'm left with the impression that in the factory the bronze wormwheel was probably heated up to fit. Anyhow, this is the spindle assembly with the parts on the spindle in their correct positions:

I checked the fit of the sleeve with its two black lockrings into the head first and deburred it for a smooth fit. Then I checked the fit of the key in the wormwheel, adjusted it slightly with a diamond stone, fitted the key to the shaft and did a couple of trial fits of the wheel onto the shaft. In..

and out:

Initially the threads behind the wormwheel dug in to the bore as I fitted it, so they got stoned and the wormwheel got smoothed with 600 grit emery, scotchbrite and polish. Eventually it was a sensible press fit. It definately can't be loose!

And so to fitting into the housing. First, put a mark on the bearing sleeve so you know where the slot for the grubscrew is. Here I started with a sharpie mark but it wasn't durable enough so it got a witness mark with a punch. This sleeve is not hardened:

The above shows the parts that have to be fitted to the spindle before reassembly. The key has to be fitted as there's no clearance in the body to do so later, the sleeve wont go over the key and the outer lockring must go on now - or you'd end up having to take the spindle out of the body to fit it. The sleeve inner lockring, the wormwheel, its thrust washer and the locknut must be stacked inside the body:

Don't forget the retaining clip for the lockring grubscrew, it doesn't have enough spring to go on later. Again, there's a copper disc under the grubscrew. Then the spindle and sleeve are lowered in. My press didn't seem to want to push it in, so I had it on a workmate on a couple of bits of wood and drifted the spindle in with a plastic faced mallet. There's no pics of this as, well, it didn't want to cooperate, it moved in slowly and I wasn't sure it was actually going back together!

When the spindle has been driven down to where the locknut threads meet the locknut, I placed two parallels between the wormwheel and the locknut to enable enough thread to emerge to get the locknut started. One's fallen out here, but this is the idea:

Then, once enough thread is visible (and as the locknut is going to be used to pull the assembly together, on thread isn't enough!) the locknut has to be started on the thread. Easy when the spindle is outside the body, about 15 minutes of coaxing with such small access:

Now the grubscrew retaining clip need to be got out of the way. The spindle was gripped in the bench vice (copper jaws!) and an ER32 spanner used to turn the nut. The body rotates freely so this went relatively quickly:

Now the bearing sleeve needs putting in the right place. Use the witness mark to align the slot with the grubscrew hole and fit the grubscrew:

Then thread the inner locknut on the sleeve and use the inner and outer locknuts to pull the sleeve so the internal threads barely appear inside the body:

For these locknuts, having bored them to 6mm to clean up my disassembly bodgery, I made up two rods with 6mm ends to act as tommy bars. I have every size silver steel except 6mm!

RobCox · Mar 30, 2023

The wormwheel locknut can then be tightened until it nips up and is just too tight. Back off the locknut a fraction. I then clonked the back of the spindle with the plastic faced mallet which jarred it to a nice slop free position. The grubscrew secured the locknut and the retaining clip was fitted.

The worm engagement is then adjusted:

This is the position of the leverwhere the worm is engaged. Tweak the grubscrew position to get a hair of backlash between the worm and wheel. Too tight and it'll bind somewhere. The gear on the eccentric bosses can now be fitted to the stub shaft. The indexing arm spindle from the side casting is then fitted and the cams adjusted to get a good gear engagement between all three gears:

Again, a hair of backlash is desirable. Then onto the easy bits. Direct indexing spigot:

A 3/8-16 grubscrew secures this in.

Spindle lock. The through bolt and short collar go in the gear side. The spring goes in the middle, the long collar goes in from the nameplate side and the handle screws on. Check the position of the handle when locked - if its not to your taste you can rotate it 180 degrees by engaging the peg on the long screw with the other slot in the short collar. I left the handle stuck up when locked, that way you can get a good grip on it:

Then the body can be sat in the base and the straps fitted. The straps are secured at the front by long bolts:

At this stage a gratuitous shot of the Behemoth sat on my mill table with a spindexer for scale:

The nameplate was fitted. I think the round headed screws are 3/16-24 BSW as a UNC tap was too big to clean the threads:

The direct indexing plate can now be fitted to the spindle nose. There are 2 sides to this, a 60 slot pattern (which I fitted facing inwards to be used) and a 56 slot side:

More quality photography - sorry.

RobCox · Mar 30, 2023

And so to the indexing plate housing and differential drive. First, fit the indexing plate lock in its hole and secure with the lever:

The carrier for the indexing plate goes in next into the central hole. Upside down next to the mounting hole:

and fitted:

The differential drive shaft goes in next. Make sure the key is installed and fit the bevel gear, with it's captive thrust washer, as the shaft is pushed in. A circlip on the end holds everything in place:

The dividing plate and sector arms can be fitted. The indexing arm shaft is shown installed here - take it out!

I need to make some C spanners to adjust these nuts, at the mo they're not tight.

Now fit the indexing arm shaft into the side of the body:

The side casting is now fitted on the pins (they're very tight!). Don't put the shaft in the side housing and then try to put it together, I tried and failed this way. Once the side housing has been driven home, secure with the 6 1/4-20 SHCS. The indexing arm can now be fitted - an we're done!

The keys have yet to be fitted - I'll leave those for @Smouser as they may or may not fit his mill. Here is the final thing in all its very weighty glory:

Smouser · Mar 30, 2023

Firstly, exceptional work with very detailed explanations :clapping:

Secondly, I am very happy that you refurbished the dividing head for me, not sure I would have been able to do it myself without a hydraulic press/fly press.

Thirdly, I REALLY hope you don't charge per hour :laughing:

Thank you very much!!!

6ply · Mar 30, 2023

Smouser said:
Firstly, exceptional work with very detailed explanations

Secondly, I am very happy that you refurbished the dividing head for me, not sure I would have been able to do it myself without a hydraulic press/fly press.

Thirdly, I REALLY hope you don't charge per hour

Thank you very much!!!

If the price is right, I have another one he can do!

fizzy · Mar 30, 2023

And me - when can you do my Cincinnati :laughing:

Stunning work really is. When you mention the size are you taking centre height or swing? Surely not centre height? My Cincinnati is a 6" centre height and is massive and stupidly heavy.

RobCox · Mar 30, 2023

Its a 5 inch centre height, not 10! :laughing:

I lowered it onto some bathroom scales... 55kg inc chuck and banjo. @Smouser carried it to my car no problem, but he's a lot younger, fitter and stronger than this old codger!
I might consider doing another in a while, but while I was doing this one I was cussing "never again"! PM me if you're serious.

RichardM · Mar 30, 2023

I don't have one that needs doing

, but you've done a lovely job with that one. :thumbup:

Smouser · Apr 23, 2023

@RobCox kindly dropped the dividing head off a couple of weeks ago.

He also made me a couple of C spanners to remove the dividing plate for when I get another plate/make a plate/bribe somebody to make a plate with the 'missing' divisions I need.

They keys on the bottom of the dividing head did not fit my mill and I simply had to remove a little bit of material equally from the keys to make them fit.

However, that ended up in a disaster with all the mishaps being my fault. Long story short, the keys were hardened, I made a load of mistakes and there was snapped milling bits and just general carnage.

Off they went into the bin and I made a couple of new keys out of mild steel.

Because I still do not have a backplate to fit a chuck to my rotary table (which is a story in itself) I decided to try and use the dividing head as a rotary table. I rotated the chuck 90 degrees on the dividing head and set it up on the Elliott TV2 mill as I had job I wanted to do for months requiring a rotary table. The mill's column extension/spacer ring came in handy here due to the height of the setup.

I did not have a chuck key for the dividing head's chuck and the dividing head refurbisher neglected to make a chuck key when it was in for refurbishment :whistle:

However, I now own all of the machines needed to make a chuck key and I started the might Warco up. I used a 'recycled' stainless steel M24 bolt as the body of the key.