[Daedalus308]

Hi everyone,

I have the opportunity to get a Kearney and Trecker Model 2H vertical mill for a very good price, but there is a slight issue. I love the rigidity of the machine, but the spindle speed is just too low for my application. How feasible would it be to replace the bearings to achieve higher speeds (assuming I swap out the pulleys in the base of the machine to trade torque for speed)? I'd also love to use cat 40 or cat 30 tooling (instead of the existing Cat 50 Taper), since it is much much cheaper. Would a simple adapter work or is it feasible to get the spindle modified? I don't know much about this machine at the moment (and I can't take it apart without significant investment into purchase and transportation), and I also don't know spindle maintenance/modification logistics and what exists on the market already. Does anyone here have expertise in this realm?

Thanks!

[awerby]

I'm afraid that trying to convert your old spindle to be faster will be a big nightmare, and your mill will be down for the time it takes to finish. It would be a lot easier to get a "spindle speeder" that works off the existing spindle for the times you need high speeds. https://www.cnccookbook.com/spindle-...d-attachments/ Or there are air-powered spindles you can adapt to your mill that are even faster and cheaper: https://www.mscdirect.com/product/details/94710449

[Daedalus308]

If we think of it more like a personal hobby project does it become less nightmarish? what would it take to convert a cat 50 spindle to a cat 40 spindle? what would it take to replace the bearings? money/logistics wise? but you're right, a spindle speed is probably a better option, but I still need to do steel with bits up to 3/8th of an inch commonly, but I just need higher rpms. what speeders can do that?

[machinehop5]

...possible you could add a VFD to the Spindle motor. 0-400 Hz would give you more rpm's...but, above 120hz the motor might fly apart.

DJ