Clausing 8520 chatter

[Defender92]

Disclaimer: I’m an amateur and I don’t know what I am doing.

Hello everyone. I picked up a Clausing 8520 about a week ago and couldn’t be happier. I bought a face mill from Amazon (This one) and mated it with an eBay MT2 threaded for my 3/8-18 drawbar. Checked it with an indicator and almost no run out.

I can make aluminum look like glass. Then I try some mild steel and I almost always get chatter. No matter how light of a cut I do.

Am I just pushing the limits of my machine??

I also adjusted my gibbs again and it helped a LITTLE. But it’s almost too tight now.

My 3/8 end mill runs perfectly on all materials. I haven’t collected much other tooling yet besides the face mill and a couple end mills.


Aluminum

one of the better mild steel cuts

one not so good

 

[ConValSam]

Am I just pushing the limits of my machine??

Yes. That face mill exceeds the MT2 collet's ability to remain rigid. If you tried taking only a half cut you might get away with it. In steel, on my machine, I would use a 1" end mill to surface that kind of face. Or try a fly cutter.

 

[ConValSam]

BTW, that's a nice looking 8520. You scored a gem!

 

[Defender92]

Yes. That face mill exceeds the MT2 collet's ability to remain rigid. If you tried taking only a half cut you might get away with it. In steel, on my machine, I would use a 1" end mill to surface that kind of face. Or try a fly cutter.

Thank you. I was worried my machine was wore out or something bad. I’m assuming non ferrous metals should be fine with this face mill as it cut aluminum just fine?

 

[markba633csi]

Are you using any cutting fluid at all? And you should have the machine set for the slowest speed possible
The inserts on those face mills often are too "blunt" and for steel require both a very rigid machine and considerable horsepower, which
are lacking on the Clausing
You would have better results in steel with conventional carbide end mills, 3 or 4 flute, 1/2" max, feeding slooowly, with cutting fluid or oil
Cutting steel really stresses the machine, as you are finding out. It's not at all like cutting aluminum, which is buttery by comparison
-M
PS also notice how tall the facemill is and the excessive stickout (distance from spindle to cutting edges), which is not ideal for rigidity either

 

[mikey]

Try removing two opposing inserts and try again. Feed conventionally and increase your feed rate a little. If the cut improves then you just don't have enough machine to use that face mill.

I agree with ConValSam - I would use a fly cutter, specifically a Tormach Superfly.

 

[woodchucker]

First, what's that black plate on the front of your table, where the travel stops go for?
Did you know there's an gitz oiler under there? It needs to be lubed.

let's start with basics.

1) Have you Trammed the head in 4 directions? If not start there.
2) Have you taken a dial indicator looking up at the shell mill and read whether all the cutters are at the same point? If not, check them all. Chineese cheap mills can be off quite a bit. throwing the head while cutting.. one goes deeper and you have a harmonic being created.
3) Have you tried taking the vise off the swivel plate and tried again? That's a place to tighten things up a bit.
4) Do you have the quill locked fully?
5) Have you tried slowing down the spindle rate?
6) Have you tried speeding up the spindle rate and lowering the feed rate? Sometimes I find speeding up (opposite of what you would think) clears the problem.
7) What was your depth of cut?

 

[Defender92]

First, what's that black plate on the front of your table, where the travel stops go for?
Did you know there's an gitz oiler under there? It needs to be lubed.

let's start with basics.

1) Have you Trammed the head in 4 directions? If not start there.
2) Have you taken a dial indicator looking up at the shell mill and read whether all the cutters are at the same point? If not, check them all. Chineese cheap mills can be off quite a bit. throwing the head while cutting.. one goes deeper and you have a harmonic being created.
3) Have you tried taking the vise off the swivel plate and tried again? That's a place to tighten things up a bit.
4) Do you have the quill locked fully?
5) Have you tried slowing down the spindle rate?
6) Have you tried speeding up the spindle rate and lowering the feed rate? Sometimes I find speeding up (opposite of what you would think) clears the problem.
7) What was your depth of cut?

A lot of these I have not tried but I will on my next day off. I’m also considering the idea a 1/2” end mill is the machines limit. I’m ok with that too.

By pushing my machine past it’s limits do I risk damaging my machine?



I don’t know what that is and I figured it wasn’t original. What’s left of an old DRO??

And that reminds me of another question. How do you oil this machine by using the oil ports? If that’s what those are. I’m currently using way oil from my lathe and spindle oil in the quill.

 

[woodchucker]

so take that off, and you will see a oiler under it.
yes way oil.. good for all.

that 2" cutter is not too much for the machine , I don't think.
Go over the basics in order. Make sure you are trammed.
How deep a cut were you taking. I'm thinking on this mill 10-20 thou is the max, I would start with 5, then go to 10...
We don't know if the vise swivel is adding to the problem so take it off after tramming.
if your head is nodded, use shims to get it level (front to back), otherwise tilt the head for left and right.

 

[woodchucker]

Also, I am noticing your gib screws on the right side are way out, while on the left quite a bit in... check your right to make sure you have a firm contact. Also I use the lock to add a bit to the gib when doing something that chatters. I want it a little tighter.

edit: I hope you know there is an oiler in the back of the table too. Very important to keep the table lubed, it does the most traveling usually.