Spindle ut of Round"???

[Tomcat104]

Help!


I have a Chinese 2.2kw spindle that is new and I fear it’s defective.

I have used it a little to do custom signs for friends and some 2.5D art. Recently I decide to build myself a router bit holder, easy enough. I designed in Aspire and made the g-code. I then took the g-code and cut it out using MACH3. I sanded, stained and varnished it. ALL the holes I cut are larger than I designed them to be. ALL of them, and here’s the ironic part, they are not all the same size (where they’re supposed to be).

I went back today and recalibrated all the axis 4 times (2 in each direction) they’re and were spot on. I then cut a .2500” hole with a .25EM (Lakeshore Carbide) and a .6500” hole with the same bit. Measured them 2x and got .3051 for the .2500” hole and .7106 on the .6500” hole. I repeated the process on the .2500” hole this time turning on the spindle and just using PGDOWN key trying to rule out MACH3. I must have measured the hole 7 or 8 times with 2 different calipers and landed on a reading of .3050 for this experiment.


I think my spindle is “out of round” but I do not know how to check it. Any ideas on this?

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[Sterob]

Put a dial indicator on the spindle shaft, and spin by hand. Any 'out of roundness' should be obvious.

[Tomcat104]

Thanks, I didn't think of that, order and have one on the way.

[ger21]

Are you just plunging straight down for the 0.25 hole?
I can't see how a spindle can be out .025. If it were, you'd probably know it right away.

[Tomcat104]

Yep just 1 plunge straight down. Is it possible to put a collet in "crooked"?

Is it possible I'm not tightening the collet nut enough? I think I'm getting it pretty snug I am disabled and seem to have it pretty tight but it's not 800lb Gorilla tight.

[ger21]

Is it possible to put a collet in "crooked"?

Yes, it is.
Did you snap the collet into the nut before screwing the nut on?

[Tomcat104]

I don't remember hearing a snap. I'll clean everything tomorrow and try it again. I'll be totally embarrassed if that's all it is. That would mean I messed up on the .125, the .25, the 4mm and the 10mm collet.

Then again, anything is possible.

[ger21]

The collet should snap into the spindle, and not fall out if you turn the nut over. It may not be a loud snap, but you should feel it snap in.

[mactec54]

I don't remember hearing a snap. I'll clean everything tomorrow and try it again. I'll be totally embarrassed if that's all it is. That would mean I messed up on the .125, the .25, the 4mm and the 10mm collet.

Then again, anything is possible.

This is how the collet needs to be assembled / loaded into the nut, some you need a twisting action

To check the run out of the spindle, you do this by checking the collet taper in the spindle, a good indicator is required to do this

[Tomcat104]

I think I have isolated my problem and it appears to be the "nut".

I hear the snap when the collet goes into the nut but it just didn't feel right so I took it out and thoroughly cleaned the nut and the collet (I thought). Put it back together and.....same problem. Took it back apart and could not see a thing.

Got out some jewelers tools and started scraping & the sanding the nut. I could feel a "burr" or high spot in the nut. Well after several hours of sanding I put it back together and tried the .25" bit and got a caliper reading of .2521" this time.

Close enough for what I need right now. I ordered 2 new nuts for it with hopes that they will be even more accurate.

Thanks guys, you put me on the right path.

[mactec54]

I think I have isolated my problem and it appears to be the "nut".

I hear the snap when the collet goes into the nut but it just didn't feel right so I took it out and thoroughly cleaned the nut and the collet (I thought). Put it back together and.....same problem. Took it back apart and could not see a thing.

Got out some jewelers tools and started scraping & the sanding the nut. I could feel a "burr" or high spot in the nut. Well after several hours of sanding I put it back together and tried the .25" bit and got a caliper reading of .2521" this time.

Close enough for what I need right now. I ordered 2 new nuts for it with hopes that they will be even more accurate.

Thanks guys, you put me on the right path.

The nuts have to be balanced, so not all, ER Nut are suitable, only buy quality brand name nuts and collets the rest are mostly junk

[Tomcat104]

The nuts have to be balanced, so not all, ER Nut are suitable, only buy quality brand name nuts and collets the rest are mostly junk

I figured as much so I chose Vortex and not something off of EBay.

[Mmpie]

The tool can be off size, if it's Chinese it could be anything.

I had a 2.2kw spindle I recently retired on which the taper wasn't ground concentric with the shaft, if indeed it was ground at all. The surface of the taper was rough and wavy and looked like chatter marks. It ran out 0.04mm IIRC, and it was a great big pile of doggy doo.


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[Tomcat104]

Sorry to hear about that. I thought that was my situation too. May still be though all test today looked promising after adding the Vortex nut.