Spindle Runout.

Well it looks like due to the Wuhan virus panic I am now unemployed. Contract has been cancelled. On the plus side it now looks like I will have plenty of time to do whatever I want and I have loads of things to keep my busy.

So here is something I want to deal with as soon as it warms up enough to work in my unheated shop. When I first got my Torus Pro it had a lot of runout in the spindle. Somewhere around .004". Going from memory I tightened the screws on the bottom of the spindle and got the runout down to about a half thou. I lived with it because I was running mostly big end mills. I now want to get rid of the last .0005" of runout. I should point out that my spindle often gets into a harmonic and squeals while cutting. The end mills when in cutting in steel tend to squeal a lot. I do have more stick out than I probably should and am aware of that. Changing feed rate or rpm for the most part only changes the pitch of the squeal. End mill life is short. I want to eliminate the runout as a potential source of the problem. It cuts well in aluminum.

So is there some sort or procedure to properly set the bearings in the spindle? I think this is where I should start.

Ok looks like my question is not going to get an answer.

New question. Have any of you measured the runout of the spindle on your torus pro? If so what do you get? Mine is .0005" although I should probably remeasure as the mill has been sitting the entire winter.

I sort of drafted up a response to you before, but I don't own a Novakon and I don't know what screws the spindle might have on the bottom? So I honestly have no idea how to help you out.

That said, your squeal sounds like chatter to me. Do you have a power drawbar?

I just checked mine since I'm in the shop . I've got no spindle runout , cold it has .0001" back and forth play . I've never had mine apart so I'm not sure how to get it properly set , but , hopefully my numbers can help foresee a target

Squeal on steel?
Try reducing the RPM by a factor of 5 maybe.

Cheers
Roger

I just checked mine at 2 tenths. Are you sure it is the end mills squealing or could it be the bearings? What end mills are you using, speeds and feeds?

Hello all thanks for the responses. I put a dial indicator in the spindle bore and the runout is .0005". So half a thou. I wrap up the mill for the winter and keep heat and a fan going inside the enclosure. We got snow yesterday so its going to be a few weeks before I really get back to using it. No insulation or heat in the shop.Mill is wrapped back up for a while.

To CL_MotoTech I do have a power drawbar and it was one of the things I checked. I tested it and it was under torquing by quite a bit. When I removed the mach 3 control and replaced it with a Centroid acorn I replaced the drawbar battery with a power supply. I have not measured the applied torque but it seems more solid when it tightens. I'll confirm that in the spring.

To RCaffin and Jmhx2 I tried every end mill I had and a wide variety of feeds and speeds. I used carbide and HSS steel end mills. 4 flute and 3 flute. I had the best luck with a 3 flute that was designed for aluminum. End mills chipped within a short time, all of them. In every case I could hear chatter its pitch would change with the different feed and rpms but it was always there. No issues when cutting aluminum though. It could be the bearings causing the squeal though. That is why I was asking in the original post about the procedure to set and tighten the bearings.

Its possible the squealing was coming from an undertorqued drawbar though. I will confirm as soon as the weather warms up a little. I'm sort of looking for ideas to pursue when I can get back to using the mill.

I'm currently fitting it with a coolant filter system. With the virus thing work has vanished so I have tons if time to work in the chilly shop.

I use 4F with steel and 3F for aluminum, carbide mostly as I tend to overload HSS.
I tend to stick with .25 & .375 end mills. I have run larger, but it seems the smaller fit the torus well.
Example of F&S that work for me on mild steel.

.25 SFM-250, Chipload .0015, Cut width 10-20% depending on the operation, 3800 RPM, 32 ipm (I slowdown lead-in to about 50%)
(It mills beautifully)

What power supply did you swap the battery with? I have been thinking about doing this.

Thanks Jmhx2 for the feeds and speeds you use. Its good to have a starting point that I know works for someone. I agree with you about sticking with no bigger than a .375" end mill. I found that worked best.

The power supply I replaced the battery with is a Meanwell LRS-350-12. It worked during testing with no issues. If you decide to put in a power supply it has to be a switching type. Luckily these are cheap. Don't use a linear type. They will blow a fuse or cook your motor. The power supply is set up only on the motor it does not power the brains of the drawbar.