Thread: Help wanted with dismantling Alexander/FP1 dividing head

Hi to all

I recntly puchased a dividing head off UkKebay for my Alexander Master Toolmaker mill- AKA a direct copy of the old manual FP1...interestingly it is exactly the same colour as the original paint on my mill yet is stamped made in germany...which seems to imply that GHA bought these in from Deckel...
either way...assuming it's made by Deckel...can anbody give me some tips in dismantling the dividing head?- its in a pretty dirty state with old oil gease and some rust and I need to strip it down completely... I'm perplexed as to how to get the dividing worm spindle out ...is there an assembly diagram anywhere available that I could refer to?

Thanks for any help

John

Well if it is "Deckel" the dismantling is pretty straight forward.

Loosen the locking clamp for the worm to worm wheel engagement. Its the one that is on the side of the head just below where the dividing plate lives.
Turn the entire body of the worm including the dividing plate counter clockwise to the stop. This will disengage the worm form the wheel on the spindle.
You should be able to rotate the spindle without turning the hand crank...(worm)


Next remove the spindle...loosen the spindle clamp (front end of the head)

Loosen and remove the ring spanner nut from the rear end of the head on the spindle. Note: there should be a cross screw in that ring nut to hold its position.
Be sure to full loosen that cross screw before attempting to remove the spanner.

Once the ring nut is off the spindle can be pushed forward and out of the dividing head body casting. It will leave behind the wheel, the rear thrust washer the protractor dial and clamp assembly.
There are keys on the spindle, but as i remember they will pass through the bore without interference.
The spindle will fit tight to the thrust and worm so some effort will be needed to remove the spindle.
Once the spindle is out the rear components can be lifted out the rear of the main body....(thrust washer, worm wheel, protractor dial and clamp assembly)

The worm can now be removed as an assembly.
Remove the clamp: There is a slotted screw opposite the handle (the one below the dividing plate) There will be a locking set screw that retains the slotted screw and prevents its turning. Remove the set screw.
Remove the slotted screw. Remove the handle . Remove the 2 inner bushing halfs that the clamp bolt passes through. (I think)
There is an Allen head bolt or screw just to the spindle side of that clamp handle...remove this bolt or screw (its the limit stop for rotation of the housing that engages the worm to the wheel....

The worm comes out as an assembly with its bearings and inner housing once the worm wheel and clamp are removed.

Cheers Ross

Hi Ross thank you very much for your very detailed description...all the features that you describe clearly- seem to be there...I've added some comments below and hopefully some photos

Will now set to and remove the slotted nut...after undoing that screw you mentioned...I've spotted the hole for that...

Thanks again

John

Originally Posted by AlfaGTA

Well if it is "Deckel" the dismantling is pretty straight forward.

Loosen the locking clamp for the worm to worm wheel engagement. Its the one that is on the side of the head just below where the dividing plate lives.
Turn the entire body of the worm including the dividing plate counter clockwise to the stop. This will disengage the worm form the wheel on the spindle.
You should be able to rotate the spindle without turning the hand crank...(worm) The spindle is very stiff when I do this hardly turns at all probably old grease corrosion etc


Next remove the spindle...loosen the spindle clamp (front end of the head) Done that

Loosen and remove the ring spanner nut from the rear end of the head on the spindle. Note: there should be a cross screw in that ring nut to hold its position.
Be sure to full loosen that cross screw before attempting to remove the spanner. Ah ...so thats the trick...the spindle has to come out before extracting the worm /dividing head shaft....

Once the ring nut is off the spindle can be pushed forward and out of the dividing head body casting. It will leave behind the wheel, the rear thrust washer the protractor dial and clamp assembly.
There are keys on the spindle, but as i remember they will pass through the bore without interference.
The spindle will fit tight to the thrust and worm so some effort will be needed to remove the spindle. I reckon its going to need some force...brass drift and a hammer oh dear...
Once the spindle is out the rear components can be lifted out the rear of the main body....(thrust washer, worm wheel, protractor dial and clamp assembly)

The worm can now be removed as an assembly.
Remove the clamp: There is a slotted screw opposite the handle (the one below the dividing plate) There will be a locking set screw that retains the slotted screw and prevents its turning. Remove the set screw.
Remove the slotted screw. Remove the handle . Remove the 2 inner bushing halfs that the clamp bolt passes through. (I think)
There is an Allen head bolt or screw just to the spindle side of that clamp handle...remove this bolt or screw (its the limit stop for rotation of the housing that engages the worm to the wheel.... taken this out...

The worm comes out as an assembly with its bearings and inner housing once the worm wheel and clamp are removed.

Cheers Ross

John:
Your head looks like the "standard Deckel" unit but to be honest i have never seen the standard one in life. Difference is at the rear end. The "Deluxe" version has a clamp system that couples the spindle to the protractor disc at the rear.
On that version you can loosen the 4 Allen's and position the protractor/rapid index plate anywhere you wish , so you can time the head to your work...a nice feature.
The standard unit is like yours, (so the books say) where the protractor disc is directly keyed to the spindle.....

The ring nut at the rear of the spindle is the adjustment for the spindle fit in the housing... The front end of the spindle is tapered seating into a taper machined into the casting....The tighter you wind in the ring nut the more you pull up the mating tapers eliminating play and also making rotation harder.... Adjustment is by taking up the nut until a good balance of ease or rotation and snugness is achieved. If you go too much you need to loosen the nut and tap the rear end of the spindle with a soft hammer to slide the spindle forward against the fit of the worm wheel and protractor disc.

Make sure all this is done with the worm (hand crank) disengaged to eliminate any chance of damage to the worm or worm wheel.....

Cheers Ross

Ross is correct (as usual) from fairly recent memory of rebuilding my Alexander dividing head, it is the "standard" head that he describes & mine too has a discrete made in Germany stamping.

Somewhat surprisingly simple & cosmetics aside could be stripped, cleaned & rebuilt in an afternoon.

regards

Brian

Can anyone shed light on this...
I'm on my 3rd Alexander and have seen a few Alexander dividing heads, all of which have a cast Aluminium dovetail cover plate painted in the same colour as the dividing head. In the pictures I've seen of Deckel dividing heads, they have what appears to be a Bakerlite black cover plate - I think the same goes for the main spindle top dovetail cover ???

The one in the pictures posted appears to have the Alexander cover but Watcherman clearly states that its stamped up as made in Germany - curious?
Regards
Paul Churchill

I have an alexander dividing head & iirc, when I mounted it on my Fp2, it did not quite match up with the Deckel t slots.

Also, are the screw threads on the Alexander imperial?

Paul

All of the covers with my machine are cast aluminium, of the few early Deckel FP1's that I have seen I dont remember any Bakelite, but I may not have been paying adequate attention of course.

I can't remember just where the "made in Germany" stamping is but it is not exactly prominent, as one would expect for something sold in the UK so close to WW2.

regards

Brian

Originally Posted by Don UK

Also, are the screw threads on the Alexander imperial?

Don

Yes, they are all Whitworth or BSF including the parts stamped made in Germany, I have yet to find a metric thread anywhere on my machine or accesories.

regards

Brian

My early FP-1 has a bakelite cover on the horizontal dovetails, but an aluminium cover on the dividing head. My guess would be the bakelite covers would get replaced with shop made alloy ones when cracked.

Greg

Originally Posted by pistonskirt

Don

Yes, they are all Whitworth or BSF including the parts stamped made in Germany, I have yet to find a metric thread anywhere on my machine or accesories.

regards

Brian

That is correct Brian but the one thing Alexanders always kept as a metric dimension was the 12mm tenon slots in the tables and the keyways under the vice, dividing head and rotary table etc. What I don't know is if the tenon slot pitch is the same as on the Deckel but I suspect that it will be. I must check the manuals.

Also the Alexander has metric (Mod 1.5) change gears with a metric bore so they appear to be interchangeable with Deckel's own gears.

Of course the big difference is in the main spindle gear which is 20 deg PA (Pressure Angle) on the Alexander and 14.5 degree on the Deckel. Since the dovetails fit each other then yes you can put a Deckel head onto an Alexander, and you can engage the gears but they will destroy each other unless you replace the driven gear in the head with one of the correct PA. All the Alexanders that I've seen have 20 deg actually stamped on the makers s/n plate. Does anyone know of one with 14.5 deg ??

Also I've only seen Alexanders with plain bronze main taper bearings, but I know of one in the UK (one of the last built) and the owner told me that it has needle rollers instead of the bronze gearing and it was described as 'more Deckel than Alexander' because of that
Anyone got or seen an Alexander with metric dials and leadscrews ??

Regards
Paul

I can confirm that the feed gears must be interchangeable with deckel as the ones that were in the machine when I bought seem more highly finished than the others and appear to have deckel numbers on them.
as an update on progress with the dividing head at the start of the thread- I can report that I ended up purchasing another one off ebay because it was so cheap...couldnt believe what it went for...so now have two to rebuild....least I know how to take it apart now...I have the other one in pieces and will post a laid out pic of the parts soon

Regards
John