# Harold Hall dividing head



## PaulL (Sep 25, 2022)

I've mentionned this project a few times in other threads.  It's getting there!
I managed two full days in the shop this weekend which has been therapeutic.  It currently looks like:






The arbor is MT3 with a drawbar to use my ER32 collets on it.  I have a plate of steel to turn into an adapter plate for my lathe chucks, and I'll mess around with that once I have this done, making a second arbor just for the chucks. 
There's a few bits and bobs to get finished, like the actual indexing pin and the locking handle, and the key to hold the gear to the shaft.
Morning was pretty boring (no, I won't stop):





My first base plate fit across just one land of my table keyways, but of course wound up without enough clearance for the nuts to hold it down.  So now it spans the table.  I might trim the end tabs down some once I get more experience with it.
Today's learnings were mostly slitting-saw related.  My first arbor colapsed on me part way through a cut:





I didn't get a good shot, but though the eventual cause was a sheared bolt, the proximal cause is that the wall of the socket the insert sits in was too thin (1mm) in material too weak. It mushroomed and deformed to one side - probably .25-.5mm bulged out.  So I swore a bit, grabbed some lunch, then made a new arbor:





This one has a 2mm flange around, a 1/2-13 thread, and fits in my 3/4" ER-32 collet.  The previous one needed a 7/8", which only worked on my nasty SYOZ collets which don't fit the lathe.  I wasn't able to machine any flats for tightening wihout breaking down the setup in the mill, so gripped it in the collet on the lathe and in a (gasp) vise-grip over some 150 emery on the end to get it snug.  I've now broken down the setup (obvs, see first photo) so I can get some flats on there next time I'm in the shop.
The other bit of learning is just visible in the photo.  I had set up the horizontal cut through the Y axis, which put the crank in a handy spot to keep an eye on it.  Wrong axis.  The thrust from the saw started pivoting the piece out - it had too much stickout in my setup.  I caught it before disaster struck and rotated it 90 degrees so the force would push into the jaws of the vise.  But that little gap in the deburring chamfer remains as as reminder.
Overall a great productive weekend.  Heck, I even tidied a bit.  It needs more than a bit, but it's getting there.  Insulation has to happen in the next two weeks so I need everything off the walls.


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## Tecnico (Sep 26, 2022)

Interesting project, looking forward to seeing it come together.  Coincidentally, I just picked up some Harold Hall reading material.

You mention "nasty" SYOZ collets, what is it that you don't like?  A handfull of those collets and a holder came with my machine.....

D


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## PaulL (Sep 26, 2022)

Funny - my First also came with a box of those collets.
The problem is that they have a narrower clamping range per collet than the ER32's.  So I use them fine in the mill, if the work fits, but I can't always get one to fit the metric sizes I've been working with - particularly the pile of metric end mills I got one day because they were inexpensive.  
And I only have the R8-SYOZ adapter, so I can't use them in the lathe.
 And for extra good measure, my set came without the 3/8.  Yay.
So they aren't totally terrible, but they aren't very available, and in the interest of standardization and tooling reduction I'm probably going to get rid of them in favour of ER32/ER40.

Paul


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## Tecnico (Sep 26, 2022)

I haven't bumped into the metric size issue yet as the cutters that came with my machine are all imperial but that makes sense.  

FWIW I bumped into a CDN supplier of SYOZ at reasonable prices, they have stock of the 3/8 size you're missing.

Machinery Canada

I spoke with Tim there and he is willing to ship by Can Post to minimize shipping costs.

D


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## Susquatch (Sep 26, 2022)

PaulL said:


> Funny - my First also came with a box of those collets.
> The problem is that they have a narrower clamping range per collet than the ER32's.  So I use them fine in the mill, if the work fits, but I can't always get one to fit the metric sizes I've been working with - particularly the pile of metric end mills I got one day because they were inexpensive.
> And I only have the R8-SYOZ adapter, so I can't use them in the lathe.
> And for extra good measure, my set came without the 3/8.  Yay.
> ...


Sometimes I use a slice out of a pop-can to shim the work in my collets. Seems to work quite well.


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## PaulL (Sep 26, 2022)

Tecnico said:


> FWIW I bumped into a CDN supplier of SYOZ at reasonable prices, they have stock of the 3/8 size you're missing


But no Canadian stock, which adds $30 for cross-border UPS :-(
I'll keep swapping to my R8-3/8" which cost all of $12 locally!


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## Tecnico (Sep 26, 2022)

PaulL said:


> But no Canadian stock, which adds $30 for cross-border UPS :-(
> I'll keep swapping to my R8-3/8" which cost all of $12 locally!


He's expecting a stock order "soon", I'm signed up for 3 sizes when that happens.  I'da thought he'd be able to shift stock within the company without the border issues.  I buy things from companies who bring in stock from their US warehouses without problems.

$12.00 & local pick up is attractive for R8, you've got good supply chain to get that price & availability.

D


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## PaulL (Sep 27, 2022)

A bit more work last night.  The arms are on:





I opened both ends of the slot with a 1/4" drill, then used a 1/4" end mill to remove the slot.  But I see my ends are larger than the slot width.  What's the right way to do this?  Use an under-sized drill?
Not like I need to remake it, but it's a bit annoying.  Of course, you barely see it in real life - photography amplifies these kinds of errors I think.

Tonight I'll try to get the indexing pin and holder done.


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## jcdammeyer (Sep 27, 2022)

PaulL said:


> A bit more work last night.  The arms are on:
> 
> 
> 
> ...


I'm sure there will be 10 experts with 10 expert opinions all different.  

Here's my non-expert suggestion.  
Use a slightly smaller drill and chain drill all along to remove most of the material leaving just enough between each hole so the drill isn't pulled into the previous hole.
Then use the end mill to make a number of passes from one end to the other.  The two end holes should not be right at the end so your milling cutter finishes the slot
Use a two flute mill.  Not a 4 flute since you are slotting, not end milling.  
If precision is really important use a 7/32 end mill (or 6mm) and drill bits.  Then do the final passes on each edge with a 4 flute 6mm to bring it out to the final dimension.


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## PaulL (Sep 27, 2022)

Yes, I certainly should not have put the holes right at the ends - I realized that the first time I slightly over-shot.  

Getting the hang of it ;-)


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## jcdammeyer (Sep 27, 2022)

PaulL said:


> Yes, I certainly should not have put the holes right at the ends - I realized that the first time I slightly over-shot.


I've lost track of the number of times I've overshot...


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## PaulL (Sep 27, 2022)

A bit of time in the shop this evening.  Only had to make this little thing twice to figure out the order.





First, cut the big bits.  Then cut the tiny shaft.  Yes, the 7mm collar is big enough for my collets to hold.  I'm not sure I could have done this with the 6" chucks I have.


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## jcdammeyer (Sep 27, 2022)

Paul,
Why is it your photos show this big long link.


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## Susquatch (Sep 27, 2022)

@jcdammeyer - My photos show the same link issue. This is not new for many of @PaulL s photos. I don't recall that we ever resolved that issue.


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## jcdammeyer (Sep 27, 2022)

Susquatch said:


> @jcdammeyer - My photos show the same link issue. This is not new for many of @PaulL s photos. I don't recall that we ever resolved that issue.


I use https://www.irfanview.com/ for editing my photos whether from my Nikon D800 or my android phone.  I can crop and set a resolution.   Then save as in a jpg file on my local system.  

I can also capture that from irfanview onto the clip board and just paste it with the text like this.  Capture on the laptop is done with CTRL+SHIFT+ALT+FCN+prt_sc where the prt_sc is the 'function' feature of the right side Shift button.


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## Susquatch (Sep 27, 2022)

jcdammeyer said:


> I use https://www.irfanview.com/ for editing my photos whether from my Nikon D800 or my android phone. I can crop and set a resolution. Then save as in a jpg file on my local system.



I use Irfan view on my desktop too. But I seldom use that anymore. My phones photo editor will do almost everything I used to use Irfan view for. The camera on my phone is also excellent - in fact, it is so good that I rarely use my digital camera for such things anymore. 

Is it really as good as a digital SLR? No. But it's good enough that one could never tell the difference for images used on the forum.


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## jcdammeyer (Sep 27, 2022)

Susquatch said:


> I use Irfan view on my desktop too. But I seldom use that anymore. My phones photo editor will do almost everything I used to use Irfan view for. The camera on my phone is also excellent - in fact, it is so good that I rarely use my digital camera for such things anymore.
> 
> Is it really as good as a digital SLR? No. But it's good enough that one could never tell the difference for images used on the forum.


I switched over to using my phone for more of the photos I post because I can email myself the photos after editing.  Occasionally I'll connect directly too.  With my Nikon I have to remove the microSD card or Compact Flash and each time I do that for one photo I think about wear and tear on the camera connector.  At some point it may no longer interface with the cards and then either not be repairable or expensive to repair.
The difference in quality between the full frame Nikon sensor and the teensy phone sensor is obvious.  Especially with cropping but again, as you said, for forum posts perhaps viewed on phone or tablet...


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## Susquatch (Sep 27, 2022)

jcdammeyer said:


> With my Nikon I have to remove the microSD card or Compact Flash and each time I do that for one photo I think about wear and tear on the camera connector.



My Canon Digital SLR has a USB Port on it that can be used to directly connect to a PC to read the camera SD card just like an external drive. Are you sure your Nikon does not have that ability? It beats the heck out of removing the SD Card all the time.

My current phone is a Samsung S22Ultra. It actually has 5 camera lenses on it! (4 on the back and one on the front.) They cover a wide range of applications.
108 MP, f/1.8, 23mm (wide)
10 MP, f/4.9, 230mm (telephoto)
10 MP, f/2.4, 70mm (telephoto)
12 MP, f/2.2, 13mm, 120˚ (ultrawide)
40 MP, f/2.2, 26mm (wide selfie)

Quite frankly, I have always maintained that phone cameras would never equal a good digital SLR. I still have that view but much less so now than before.

Mine even has a pro mode where you can control exposure, focus, aperture, exposure lock, and many other pre-photo settings. In fact, it even has an anti vibration stabilizer that works incredibly well! It's amazing really.

No, it cannot possibly equal the advantages of big glass but it is still quite amazing to see how well it compensates for what it lacks in big lens size. It will even take hand held pictures of the stars without a really long exposure. (You have to see that to believe it!)

I have not scratched the surface of its video recording capabilities.

The zoom lens has a mechanical zoom on it but like any decent digital camera you can always use a digital zoom either before or after taking a photo too. I typically crop and resize my photos right after taking them without bothering to save the original.

I bought the phone out of my service contract war chest fund after dropping the old phone off a 20ft scaffold and cracking the display. No regrets. Wife accuses me of doing it on purpose......


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## jcdammeyer (Sep 27, 2022)

I too am impressed with my Samsung.  
And yes, I do have the USB connector on the Nikon too.  But it's slower than the USB connection on the phone and doesn't charge the camera battery so if I forget... 

What I like about the Nikon is my MACRO lens.  And the ability to set the depth of field.  Not as easy on the phone.


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## Susquatch (Sep 27, 2022)

jcdammeyer said:


> What I like about the Nikon is my MACRO lens. And the ability to set the depth of field. Not as easy on the phone.



Yes, I have not figured out how to come close on that one yet either. Even if I do, I expect that lighting will be an issue as the phone will no doubt block any external lighting and the flash is a point source that totally F's up the coverage. The best I have been able to do is to use a telephoto lens setting zoomed right in from a short distance (which means I can't control depth of field as well). I use that trick often to see details that my eye would never be able to see. But it doesn't even remotely equal my SLR macro lens with surround lighting. 

I doubt the phone manufacturer cares about macro photos like that though so I'm not holding out any hope that it will get better.


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## Susquatch (Sep 27, 2022)

@jcdammeyer - we have probably sideswiped this thread way more than reasonable. So let me just add one thought and then disconnect.

Do you know what I hate most about my phone camera?..... It is so good that I almost always forget to pack my SLR when I go places and then I have to live with the differences that do exist when they arise. Conversely, what I love most is that I don't have to bring my SLR along anymore because my phone is always in my pocket. Damned if I do and Damned if I don't! LOL!


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## jcdammeyer (Sep 27, 2022)

Amazing how difficult it is to photograph a black twizzler.





And yes.  I don't take my camera along as often either.


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## PaulL (Sep 27, 2022)

I am a lazy technologist - photos go from my phone camera into Google photos, and from there I copy to my clipboard and paste into the text box.  That long string is google's unique ID for that copy/paste.  Everything else I've tried makes a round trip through my filesystem and makes me pick filenames and all sorts of annoyance. 
Interestingly, I don't get the big superimposed filename when I look at my threads.


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## Susquatch (Sep 28, 2022)

PaulL said:


> I am a lazy technologist - photos go from my phone camera into Google photos, and from there I copy to my clipboard and paste into the text box.



I am even lazier. I don't use a desktop to post here. I use my phone. So photos can be directly taken and inserted into my thread as I type using the attach file functionality.

In other words, I type along till I need a photo, then click on "attach file", and then I can choose the camera as a source or browse my google photos and insert from there, and then resume typing. Easy peasy.


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## PaulL (Oct 7, 2022)

And it's done!  The tension on the two 1/4"-20 nuts manage how loose it is when the main locking lever is not engaged - in other words when adjusting the rotation.  Then the locking lever holds everything in place.
I'm surprised how rigid the whole assembly is, even with the ridiculous-looking stickout of the M3 ER32 holder.  In a different world more of the M3 would fit in body of the indexer, but dimensions on the stock didn't seem to allow it - the spindle would interfere with the two locking bolts.

Here's an action shot, being used to make its own locking lever:





My only real disappointment with it is that milling the keyway into the arbor I *totally* messed it up.  It has too much slop, and all my (well, all 3 of cheap chinese) sub-4mm end mills are trashed, to no avail.  I'm doing something very wrong with those little end mills that's destroying them as fast as they meet the steel.  I'll cut a fresh keyway on the opposite side of this terrible one when some less cheap mills arrive - maybe they will work better?

Paul


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## YYCHM (Oct 7, 2022)

How many teeth are on that indexing gear?


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## PaulL (Oct 7, 2022)

YYCHM said:


> How many teeth are on that indexing gear?


60 on this one.  It's one of the change gears from my lathe.
With 60 teeth I get 120 divisions - 3 degree precision.  Each tooth provides two positions, one with the pin in the gullet of the tooth, and the other with the pin rotated 90 degrees to expose a gap in the pin that engages the top of the tooth.


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