Increasing The Number Of Jet JVM 836 Milling Machine Speeds

[Buffalo20]

Its that time of year, sporadic work, 70 hours last week and 9 hours this week, on and off all summer, so I'm setting in the home shop, on Hot Standby. I got a PM (on another site) about a machining job I did about 10 years ago, about increasing the speeds on my Jet JVM 836 milling machine. So I had to go back and find some pictures and the original drawings, of what I did. So I thought I'd also post the pictures here.

I know I could have gone with a 3 phase motor and a VFD, but all of the parts were in the shop and it was early shop project, that ended up working perfectly.

The insert or "transmission" increases the number of speeds on the mill from 5 speeds, ranging from 250 to 1500 rpms, to 25 speeds, ranging from 48 to 1550 rpms.

 

[Grandpop]

I like it! I have an Enco 8 x 36 that had 12 speeds with 3 pulleys. Speeds were 215 - 3400. I moved the motor drive pulley up one row which didn't do much for the speed range, but it provides 215 to 1000 with 100 rpm steps; speeds that I use most.

I like your idea, and will look at mou ting the motor on top instead of the bottom. I do not see any slots or way to loosen/change the motor belt - how do you handlethat?

 

[Buffalo20]

there are slots on the bottom plate, to tighten the inside belts, and studs to tighten the motor plate/belts, using the motor plate slots.

 

[KBeitz]

I hate those plastic belts...