Atlas benchtop mill: model MFB - Marvin Head question

[john.kovalcik]

Hello,

New member here. I have the subject mill - bought off a neighbor a year or so ago and have tinkered making some rebar bottle openers but now interested in learning how to use it better. I have the Marvin vertical head - I didn't know this was an aftermarket (and desirable) option. I also just figured out I have auto feed as well. So a little more excited about figuring out how to better use and maintain it. It is in very good shape - but I need to ensure it's oiled properly and might need some belts. Anyway - to my question - I've noticed that the Marvin head will tilt on the vertical slightly as I'm using. I checked the shaft mounting bolts and both seem very tight. Any tips/suggestions? I really don't know what I'm doing, learning as I'm going here. The head will also make quite a racket - off and on - lately more on than off - I can't tell if it's the belts, pulley's or bearings to be honest. It comes and goes but is more there now. Much appreciated. Here is a picture of it - you can see what I mean by the head rotating slightly as/during use. Also - what is that "T" bar that just sits in the top of the head for?

 

[markba633csi]

As far as I know the Marvin head was not intended for heavy duty use- it's an add on that gives some vertical functionality to
the Atlas horizontal mill- I believe the mounting arrangement is a known weak point on those. The "T" bar looks homemade.
Check the cutters you are using- if they are dull it will increase the cutting forces, especially in steel. Choose the shortest possible
cutter to do the job when working tough materials like steel- the one pictured looks excessively long

Rebar is a poor material to work with- probably the lowest grade of steel on the planet; and has some hard inclusions/impurites
that can ruin a cutting tool very quickly. Ditto for bedframes
Welcome to HM!

 

[john.kovalcik]

Thx for the info markba633csi. I think you are right about the T-bar - it just sits right in this hole on top figured it was used for something. Agree - believe the entire mill is for light duty, hobby/home use. I have to learn to use it in the manner for which it was designed! I'll have to look into different/shorter cutters - that one is indeed excessively long - I try to use the teeth as far up as possible to minimize the torque. all great info - thanks again

 

[markba633csi]

I think you'll find the machine does a fine job on aluminum and brass, but tends to struggle a bit on steel- use LOW spindle speeds and
plenty of cutting fluid for steel work
You might want to spend some time snugging up the gib screw adjustments for the table and the knee, since any play
there can cause chatter which can damage your cutting tools and leave rough finishes
Remember also you can put an endmill in the horizontal spindle and cut that way- sort of like a vertical mill on it's side- and have
more capacity for heavier cuts. I often do flycutting with my horizontal mill that way.
Ideally you want smooth movement of the machine axes with some resistance without binding up- it can take some experimentation to find a good compromise on the adjustment screws
Endmills can be expensive but you can often find mixed tool lots offered on Ebay from estate sales for reasonable prices