Information required for making Meccano Spur gears

This topic has 9 replies, 7 voices, and was last updated 12 January 2023 at 15:35 by SillyOldDuffer.

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11 January 2023 at 10:30 #628615
Greensands
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@greensands
Has anyone had any experience in making and can expound on the technical details of Mecanno type spur gears? A search using the keyword option on this forum has not come up with any finds. As a kid I remember having a number of gears in my collection including bevel gears. The spur gears i seem to recall were made (or punched?) from brass sheet with a boss for attaching to a 5/32" (?) diameter shaft and retained by a small slotted grub screw. Any further information would be much appreciated.
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11 January 2023 at 10:30 #16419
Greensands
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@greensands
11 January 2023 at 10:40 #628620
John Haine
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@johnhaine32865
**LINK**

20 degree PA –

**LINK**

Something else that Google threw up was that they can be hobbed with a 9/16" BSW tap, but that would suggest a different PA.

I wouldn't rely on the forum search unless I know that I'd seen a posting on a topic. Google is your friend.

Edited By John Haine on 11/01/2023 10:41:42

Edited By John Haine on 11/01/2023 10:42:51
11 January 2023 at 10:55 #628624
Howard Lewis
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@howardlewis46836
Some time ago, there was a thread on here, an article in MEW, about this.

It gave details of the gears, (DP etc ) and there was a pictire of pinions being produced as a long length, before being parted off.

Howard
11 January 2023 at 11:07 #628626
Greensands
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@greensands
One for the Mods – Could you please arrange to correct the spelling of Meccano in the title line of this posting. Thank you
11 January 2023 at 11:27 #628631
JasonB
Moderator
@jasonb
Good number of original Meccano drawings here including the 38DP gears

Photos of gears being hobbed on a machine made from Meccano and the article that goes with it

Edited By JasonB on 11/01/2023 11:38:57
11 January 2023 at 15:42 #628657
duncan webster 1
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@duncanwebster1
38 dp! We're they just trying to make life difficult?
11 January 2023 at 15:51 #628659
JasonB
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@jasonb
If you follow the other links it was so the gears worked with their 12tpi racks which were a 55deg V form
11 January 2023 at 23:22 #628743
Georgineer
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@georgineer
Posted by JasonB on 11/01/2023 15:51:11:

If you follow the other links it was so the gears worked with their 12tpi racks which were a 55deg V form

That makes sense. Back in the 1960s I wanted a left-hand Meccano worm gear. With my metalwork teacher's help I established that the standard worm gear is actually a 12 tpi Whitworth thread (9/16" daimeter if memory serves), so I cut the equivalent LH thread on a length of brass and made my own worm gears. I even bought my own 5/32" BSW taps to cut the thread for the grubscrew.

The school, for some reason, didn't have a left-hand thread chaser, but the right-hand one did a perfectly acceptable job.

I've still got one of the LH worms knocking around the place somewhere. And the taps…

George
12 January 2023 at 15:35 #628867
SillyOldDuffer
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@sillyoldduffer
Back in 2016 this experimental rack-cutter was made to produce Meccano gears:

Have a read of this thread.

Note that the second picture shows a plastic gear meshing with a faulty aluminium gear, which damages both of them. The way I held the gear in the chuck with bolt and mandrel was unsatisfactory because the blank tended to shift whilst cutting. Bad error on my example, see teeth near 4 O'Clock. Went in the bin after being photographed!

The gears are only nicely cut if they don't slip and the operator turns the rotary table correctly!

Dave
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