3.7:1 Jigmaster with three (or four) dogs on the bridge.

[mhc]

I've put together a 3.7:1 gear set using a jigmaster 5-500 main and an older surfmaster 13-250 pinion with 13 teeth - the 4:1 jigmaster and newer surfmaster 13-500 pinions have 12 teeth. I got the idea reading the linked thread on the 250 recently http://alantani.com/index.php?topic=17571.0

The 13 tooth surfmaster pinion is on the right;



I had also been working on a three alternating dog bridge using a stainless Cortez Conversion 98-155 gear sleeve with 9 teeth on the ratchet. I used the 98-155 because the smaller ratchet allows more room for the dogs and springs. Looking at the close up photo I can now see the second dog needs to be fine tuned to sit flush with the face of the ratchet teeth.



I filed the flats on the sleeve shaft all the way down to take one of Alan and Bryan's thin under-gear metal washers made for the gen 2 sleeves. It got a bit busy under the gear with 3 dogs and springs and I wanted a metal washer to cover it all and protect the delrin washer.



The bridge was intended to be drop in but I ran out of room with the spring for 3rd dog and needed to grind about 1/8" off the plate near the bridge screw -again! (this was my second attempt)



Put it together with a 3/0 Alan T grip and SS handle.



When I first put it together the spool and pinion didn't engage - I had checked the pinion fit over the bearing/bush in the side plate and fit on the spool shaft before I started. I pulled it apart, couldn't see any problems and put it back together and it worked fine. The yoke might have been getting caught up  
The gears ran smoothly in a light test - I put it on a rod and winched a 2 litre (~4 lbs) water bottle around 12' vertically a few times. I had done the same with 5:1 newell gears in a 501 the day before and as you would expect, the 3.7:1 gears take noticeably less effort to winch a dead lift.

Mike

[Alto Mare]

Mike, 3-dogs on that tiny plate? you're a mad scientist ...I love it!
Keep it up, your projects are exciting to see.

Sal

[Tiddlerbasher]

Mike - So you had a 3 dog night then

[mhc]

Mike, 3-dogs on that tiny plate? you're a mad scientist ...I love it!
Keep it up, your projects are exciting to see.

Sal

Thanks Sal, but I wouldn't call myself a scientist 

Mike - So you had a 3 dog night then

Haha - no it's summer here, that's why I put the dogs out on the bridge.

[Bryan Young]

Sick brother. Sick!!!

I would love to hear that click click click

[coastal_dan]

Mad Scientist for sure!  Some really innovative and outside of the box coming through these days.  Flippin' sweet by any standards.  Thanks for sharing with us!

[steelhead_killer]

Post a video with sound...   I too would love to hear it!

Andy

[Rothmar2]

From the movie Snatch.....

"The one punch machine gun....Mickyyyyyyyy!!!"

Micky The Jigmaster!
I know you've had this one on the go for a while, it's nice to see it revealed to everyone. I reckon I'll give this a shot on the Frankenjiggy down the track.

[Tightlines667]

Good work here!

[mo65]

   I too would love to here the triple dog music...I know alternating doubles sound awesome. I love these innovative builds...great work!!

[steelfish]

I still see some room for the 4th dog over there

[mhc]

I would love to hear that click click click

It's not that loud really, the springs are soft and the ratchet teeth are small, but it is fairly constant.
Andy and Mo, I'll see what I can do about recording it, and maybe compare it to a 16 tooth 750 SS ratchet - now there's a machine gun!

I still see some room for the 4th dog over there

Four? - now that is mad, and just silly   ;D...........although I might have looked at it when I was hoping to make it a drop in bridge, but couldn't see how to fit the fourth without modifying the plate. Now that I've modified the plate anyway, a bit more grinding can't hurt. Hmm...standby.

Mike

[mhc]

Different bridge but same concept - I haven't cleaned up the 4th dog and need to trim a little off the post - but yes, Alex and Fred, there is room for a 4th dog! I'll clean it up, modify the plate a bit more, and file the flats on the sleeve so I can cover them with a metal washer later in the week - but it seems to work okay - even if it is a bit silly  

[Bryan Young]

Man, you have some serious skills?

[Newell Nut]

A lot of people say Newells sound like a coffee grinder. This one could really play a mean tune.