Author Topic: Dividing head  (Read 82046 times)

Offline mattinker

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Dividing head
« on: July 23, 2013, 03:36:07 PM »
I had a surprise when I opened John's thread, I've been working on the same thing! I'm not making a film of it though.


I bought the book, I could have made from the photos, but it's a good reason to buy a good book.


Like John, I've made most of my patterns in MDF, but the dust is really bad, so this is pine that I have lots of from my TV set  building work.

 I didn't have anything round, but that's what we have lathes for!




I planed down the two sides of the base to give it draught.



glued together, with grubby finger marks in the glue!



I didn't have any 8mm dowel, so I drilled a hole in a piece of scrap and drove a piece of pine through with a malet, thus making five times more dowel than I needed!




A piece of broom handle to make the split cotter boss.


Cutting the pattern in half with the band saw, I had to use two blocks to keep it vertical. You can't see it, but the draught on the bottom made it really unstable.




Body filler fillets and hole filling. Pine requires much more finishing, but I'm not ill as I would have been with MDF!

I won't be casting until the heat wave is over!

Offline doubleboost

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Re: Dividing head
« Reply #1 on: July 23, 2013, 03:52:01 PM »
Looking fine
You must be in to wood as you have one of those wooden hammers
Be interesting to see how we do things
John

Offline mattinker

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Re: Dividing head
« Reply #2 on: July 23, 2013, 04:53:37 PM »
John,

I'm a fan of your videos!
I'm looking forward to seeing your way of doing the same thing as me! I have always worked in metal, it's just I'm a tool junky, I earn my living partly in wood, so I have the tools.

By the way, I was a vehicle fitter for ten years!

Regards, Matthew

Offline vtsteam

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Re: Dividing head
« Reply #3 on: July 23, 2013, 09:15:06 PM »
Great to have two people working on the same project! I enjoy pattern making so it's good to see you both making them. I also sent for Sparey's book after Rob Wilson recommended it so highly -- but mine is taking quite long to get here. I'll be watching and enjoying your thread!  :thumbup: :clap:
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline Mayhem

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Re: Dividing head
« Reply #4 on: July 24, 2013, 01:50:10 AM »
Nice work Matthew - I'm looking forward to seeing this progress.  I'm watching John's progress as well but over on the MWF site.

...You must be in to wood as you have one of those wooden hammers...

So that is the defining feature?  :lol:

Offline vtsteam

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Re: Dividing head
« Reply #5 on: July 24, 2013, 09:05:16 AM »
I'd say using a dowel plate is a definite indicator. And making the dowel plate puts you on the metal working side as well. Wouldn't be surprised if he made the mallet, too.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline mattinker

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Re: Dividing head
« Reply #6 on: July 24, 2013, 01:47:48 PM »
I'd say using a dowel plate is a definite indicator. And making the dowel plate puts you on the metal working side as well. Wouldn't be surprised if he made the mallet, too.

I bought the mallet in the UK along with the Stanley 30mm chisel which is at least 2" shorter from sharpening, I left in '79 when Thatcher arrived!

Regards, Matthew

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Re: Dividing head
« Reply #7 on: July 27, 2013, 02:45:49 AM »
 :clap: :clap: :clap: Looking great Matthew  :thumbup:



Rob

Offline mattinker

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Re: Dividing head
« Reply #8 on: July 27, 2013, 06:02:36 AM »
Things haven't changed much, more painting and filling.


The Emco is the smaller of my two lathes (tool gloat, gift from a school, brand new with protective gunk, missing the burnt out motor and pulley!), so the dividing head is sized to fit.

Raiser block to make the dividing head more usable on my Colchester.

Cutting out the riser block on my radial arm saw, set to 3, the draught is made on cut out. It's hard to show draught as camera deformation is often more than enough to cancel it out.


The banjo

Offline doubleboost

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Re: Dividing head
« Reply #9 on: July 27, 2013, 06:16:29 AM »
Very nice
The pattern as well as the lathe  :drool: :drool: :drool: :drool:
John

Offline Chuck in E. TN

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Re: Dividing head
« Reply #10 on: July 27, 2013, 08:42:37 AM »
Matt, what are the dimentions on your lathe? It looks similar in size to my 7x14. Wish I had the t-slotted cross slide on mine.
Chuck
Chuck in E. TN
Famous TN last words: "Hey ya'll, watch this..."
MicroMark 7x14, HF X2 mill, Green 4x6 saw. Harbor Freight 170A mig

Offline mattinker

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Re: Dividing head
« Reply #11 on: July 27, 2013, 10:09:58 AM »
Chuck,

The Emco Compact 8 is an 8x18. The "T" slots are nice, but only 6mm, I think I'm going to make a few raising blocks, because I'll need to be able to use it on my mill (14mm "T" slots) and my shaper (12mm "T" slots). None of my machines have the same distance between slots!

Regards, Matthew

Offline krv3000

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Re: Dividing head
« Reply #12 on: July 28, 2013, 08:50:19 AM »
hi mat same lathe that i have

Offline mattinker

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Re: Matt's Dividing head
« Reply #13 on: August 15, 2013, 11:57:21 AM »
hi mat same lathe that i have

Krv,

I'm very pleased with the Emco, my first screw cutting lathe!

On to the casting, when I started looking at the dividing head project, I spent some time thinking about the casting. Three things came to mind:-

i.From my little experience of casting, I thought that I'd never manage the gap the middle, so I left it out.

ii. The original being made of cast iron, (I presume) so I made mine with fatter flanges to have a stronger base.

iii. My banjo pattern I made without the ribs as I thought that they would make the moulding more difficult. Rob Wilson had told me that the ribs were to make the milling easier on the lathe so that decided me!

It's been nearly ten years since I cast anything, I've been preoccupied with my major home and workshop building project. I had bought "regenerating paste" for my petro-bond sand, it was already in need of reconditioning when I left it, now, it was in a sad state, so, first things first, re-work the sand, by hand, a couple of times, as I didn't want to overdo the "paste" and I just couldn't remember what it felt like when "right". It took four goes at ramming the mould before I got it right, without forgetting the the breathers, having it collapse and the worst, putting it on backwards, as I hadn't put eccentric guides to make it go back only one way!

I've been following John's excellent videos very closely, I owe him my gating (Thanks John!!).


It had been so long since I'd done any casting, that I really hadn't much of an idea about how to go about it! I realised that my pattern was smaller than John's and probably less volume, so if his last casting wasn't too bad (I couldn't see it in the video), mine might work out. So between John's videos and the US Navy Casting Manual, I went with a 30mm diameter sprue and a 50mm hot riser with a fairly generous gate.





Scatter brain forgot the breathers on one ram up, when I opened it up again, the sand collapsed, I rammed it harder for the next one!



I don't remember where I found this idea, so I can't give credit to it's inventor. It gives a nice smooth sprue funnel easily




my foundry.



I broke the lid a long time ago, so it's two firebricks for the time being!


The result, with which I'm pleased (Thanks again John!)





So while I'm at it, it's time to ram up the banjo and the riser block!

Regards, Matthew
« Last Edit: August 15, 2013, 01:15:50 PM by dsquire »

Offline doubleboost

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Re: Dividing head
« Reply #14 on: August 15, 2013, 12:01:22 PM »
Very nice
There is much more metal in mine
That is why it was a ba&^%$d to cast
John

Offline vtsteam

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Re: Dividing head
« Reply #15 on: August 15, 2013, 12:46:39 PM »
Seems like you picked up casting easily again! Looking forward to the rest of the build.  :thumbup:

That's an interesting sprue cutter!

I've been tapering my sprues lately just by choosing a dowel of the bottom diameter desired and rapping it from all sides at the top to form a taper before removing it. Works well and makes a nice smooth sprue surface with no cleanout needed.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline mattinker

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Re: Dividing head
« Reply #16 on: August 15, 2013, 05:15:26 PM »
John,

what's the centre height over the cross slide on your Boxford? The Emco Compact 8 is 60mm I'm curious to know how different the projects are!

VT,
I picked up the casting with quite a lot of glitches, the thing that I hadn't quite remembered was how much of a buzz casting is, such a satisfying thing to do!!

Regards, Matthew

Offline micktoon

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Re: Dividing head
« Reply #17 on: August 15, 2013, 05:27:04 PM »
Looking good Matthew, glad the castings came out well, there will be no stopping you now.
  Cheers Mick.

Offline mattinker

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Re: Dividing head
« Reply #18 on: August 16, 2013, 04:40:00 AM »
Thanks Mick,

I'm enjoying myself, just need to keep on finding the time!

Regards, Matthew

Offline Meldonmech

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Re: Dividing head
« Reply #19 on: August 16, 2013, 05:36:09 AM »
Hi Mathew,

                      Good result on the casting, should machine up well.

                                                                                                        Enjoy the buzz    Cheers David

Offline mattinker

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Re: Dividing head
« Reply #20 on: August 17, 2013, 02:01:59 PM »
Hi,

I got two more moulds rammed up, The Banjo casting and two riser blocks.


This is not the actual mould that I cast, I forgot to take the pics, but it's nearly the same




I made the banjo with out the raised ribs in the original, I think that I'm not steady enough to pull of a casting with that kind of detail!




Well, the casting is done, I don't know when I'll be able to get to start machining, it will be as soon as I can!

Regards, Matthew

Offline doubleboost

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Re: Dividing head
« Reply #21 on: August 17, 2013, 03:44:56 PM »
John,

what's the centre height over the cross slide on your Boxford? The Emco Compact 8 is 60mm I'm curious to know how different the projects are!

VT,
I picked up the casting with quite a lot of glitches, the thing that I hadn't quite remembered was how much of a buzz casting is, such a satisfying thing to do!!

Regards, Matthew

Hi
Matthew the distance between the cross slide and the lathe centre is 70 mm
John

Offline mattinker

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Re: Matthew's Dividing head
« Reply #22 on: September 26, 2013, 08:00:39 AM »
Hi,

it's been a while! Things keep getting in the way. I've been working on the casting, starting with a skim over the top. With two 4mm rounds to compensate for the draught.



The boss for the cotter was a little proud, which meant that once milled, I had a small flat to seat it on.



The base trued up really well and I got a finish that I was really pleased with after taking off 1.5mm. Leaving the centre height



The "T" slots on the Emco are only 6mm wide, which is going to have to be OK!




Drilling 5mm holes for the guide pins.



I drilled four locating hole holes, so that I will be able to line up the dividing head at 90s as well as in line with the spindle.



Locating pins, slotted with my hacksaw.



Tapping M6



Pins in line with the spindle.



90s



Lining up to drill the split cotter hole.



First step drill, 6mm.



Drilling out to 15mm.



Finishing with a 16mm slot drill, I haven't got a reamer that size. Split cotters are pretty forgiving!



Before I could go any further, I needed to make "T" bolts. I used a piece of hot rolled  10mm square bar, it was slightly oversize, cleaning it up with a file brought it down to size. A light came on, I'd never thought about using my self centring punch on square stock before!



Popped!



Centring in the four jaw.



Centre drilling.

Offline mattinker

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Re: Matthew's Dividing head
« Reply #23 on: September 26, 2013, 08:43:26 AM »
Oups! I hit the post instead of the preview button!



Facing off.



Drill to 6mm



cutting off four pieces with the the bandsaw.



I turned the heads off for 6mm bolts.



The bolts were then brazed into the square heads.





Faced up and cleaned up with a file.



I had originally intended using brass for the split cotter, but I kept on having a doubt about brass in Al, I actually made one in brass, but I decided against it after a bit of reading on the web. I am going to bore with the cotter in place. So, apiece of 16mm clod rolled, 55mmlong was chucked up in the three jaw.



Trued up and centre drilled.



Drilled all the way through 5mm, taping size for 6mm.



Starting the tap by hand.



Tapping 25mm deep.



I then turned the part around in the chuck and drilled 6mm, clearance 6mm bolt to a depth of 30mm. I'll explain all this once the casting is bored.



So this is what it looks like so far on the Emco.

More later, regards, Matthew


Offline PekkaNF

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Re: Dividing head
« Reply #24 on: September 29, 2013, 02:25:13 AM »
Would you elaborate a bit of this split cotter design consideration? I'm familiar. with the design and have this same book and read some further info, but haven't used this method yet. Therefore I'm interested to hear reasoning about the material choices you made.

Pekka