Help !

[Nick Worrall]

Can anyone give me an idea of what's going wrong here ? It's bright mild steel, I've tried different feeds and speeds and different tools but this is the finish I'm getting. Sorry if this is in the wrong section.
Many thanks in advance.

 

[mfrick]

The pattern left on the material is casued by the gears in machine It is a gear pattern

mike

 

[ignator]

Can anyone give me an idea of what's going wrong here ? It's bright mild steel, I've tried different feeds and speeds and different tools but this is the finish I'm getting. Sorry if this is in the wrong section.
Many thanks in advance.

This looks like your using the side of an end mill, is that correct? If so 2, 3, 4, 6 flute? Diameter of mill? Deflection can be an issue. How light of a cut are you doing? Too thin of a feed may result in rubbing vs. biting in. Power feed on the axis, or is this hand cranking where erratic axis movement occurs?
A fly cutter may produce much better surface finish.
I have a belt driven mill, and have seen this same surface finish. Sharpness of mill, especially low cost China imports, that are NOT HSS, but sold as such.
For RPMs if you take the diameter of the end mill, multiply by pi (3.14), for circumference, times spindle speed rotations per minute, you should be around 100 feet per minute or 30 meters (convert the mill diameter to meters or feet first) per minute for cutting mild steel.
Don't know if this reply helps you.

 

[doc1955]

Clean your spindle and collet it most likely is caused from cutter run out. Put an indicator on the end mill and check I'm guessing you will see run out in the cutter and it could be caused by dirty spindle, bad coller or loose or bad spindle bearings.

 

[Werkstattkrabbe]

Hello,
would say that this could be a problem with the stability of the axis guidance. Check the wedge bar.
Or also an axle lubrication problem, sometimes the lubrication
control.
Or the connection with a non-sharp tool, although the cut surface looks good.
Greetings

 

[johwen]

It looks like a climb milling pattern to me? but if your lathe or mill is belt driven it can be caused by hard spots in the belt. Chinese belts were a bit notorious for this. Try another belt as the hard spots ride up the V in the pulley if this is the case
John

 

[Nick Worrall]

Thanks for your input guys, very much appreciated. It turned to be loose gibs (and my inexperience)