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New from Old / Re: Boxford back from the dead
« Last post by Sea.dog on Today at 08:00:03 AM »
The large backgear is a press fit, at least it is on my spare. You may have a mix.

14.5 gears have a rounded root whereas 20 is flatter, or is it the other way around? Whichever, you can see the difference between the two from both the root profile and tooth profile.
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New from Old / Re: Boxford back from the dead
« Last post by AdeV on Today at 07:33:58 AM »
Thanks again for the info - Im wondering now if the pulley set is original or not - as it is in mesh with the small gear, which is 20pa. Its possible that the driven gear on the back gear shaft is the original 14pa, as it is pinned to the stamped shaft. Looks more and more like I need to go buy some plasticine at lunchtime  :thumbup:
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The Water Cooler / Re: Anyone remember this film ?
« Last post by awemawson on Today at 06:54:53 AM »
My Father had an office in Bradford and we lived in Leeds so he went past every day in the car (series 1 1949 Tickford SWB Landrover now worth a fortune! *). On those rare times when we went with him - probably school holidays I suppose - he didn't stand a chance - we HAD to stop. I can remember getting first world war candle lanterns with a slit window, loads of optics - prisms, lenses etc - and a load of aluminium aircraft solenoid valves that we sawed up to recover the solenoids to operate the points on our Hornby Double O train layout. It was an absolute Aladdin's Cave. The war wasn't that long over and presumably the government was unloading as much as possible to pay off the lend-lease debt. I have a feeling that my older brother is still using those solenoids as he has the (now much extended) layout !

(* Identical to the picture but ours was NNW514 - sold for 50 by my brother back in the 1960's  :bang: )
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New from Old / Re: Boxford back from the dead
« Last post by Sea.dog on Today at 05:45:09 AM »
Pretty much as expected, the backgear is from a later machine. The PA was changed in the '50s so the 14 is a pretty rare animal. Broken teeth are quite common when chucks get jammed. Since there's no way of locking the spindle until we get to the MKII the usual method is to engage backgear as a lock. Bull gears do come up for sale from time to time and the chap I spoke to does have a set available.
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The Water Cooler / Re: Anyone remember this film ?
« Last post by hermetic on Today at 05:24:39 AM »
I dont believe it!!! I had one of those as well, I will ask my mum what it was called!! My dad loved that shop too!
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New from Old / Re: Boxford back from the dead
« Last post by Sea.dog on Today at 03:49:25 AM »
It definitely looks to be 14294, doesn't it? I've asked for any info on these gears on one of the Boxford forums. I'll let you know if there's a reply.

BTW, the large gear is called the Bull gear.
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How do I?? / Re: Maths help please: Approximating a Flat Iteratively
« Last post by AdeV on Today at 03:37:25 AM »
 :doh: Obvious when you know! Yes, you're right, my Interact has the QC30 spindle which uses a ring to push the tool into the taper from below. No automatic tool changes for me!
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New from Old / Re: Boxford back from the dead
« Last post by AdeV on Today at 03:27:08 AM »
That's not that crude, and sounds effective! If you'd called it "modelling clay" it would seem positively professional!

Looks like there's some Plasticine on my shopping list now!
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New from Old / Re: Boxford back from the dead
« Last post by awemawson on Today at 02:48:19 AM »
You can visually determine whether the pa is 20 or 14.5 by my crude but effective method:

Roll the gear in Plasticine to create the correct meshing rack. Cut longitudinally with a sharp razor blade and look in profile at the flank of the rack teeth which for an involute gear should be a straight line. This flank angle IS the pressure angle. The difference between 14.5 and 20 degrees can easily be determined with a cheap school plastic protractor.
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How do I?? / Re: Maths help please: Approximating a Flat Iteratively
« Last post by awemawson on Today at 02:37:00 AM »
The 'pull stud' is what pulls the 40 taper tool shank tightly into the female socket in the milling machine spindle. It is gripped by a special finger collet. The arrangement performs the same function as the draw bar on a Bridgeport manual mill. Your interact of course has no draw bar as its presumably a QC30 nose?

Using the pull stud allows for automatic tool changing. There are many shapes in use and Beaver of course HAD to design their own  :ddb:
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