Atlas horizontal mill support arm

[Airpirate]

I aquired an old Atlas horizontal milling machine model MFC. The arbor support appears to be mounted backwards on the support arm, the busshing that would hold the arbor is facing away from the spindle. I removed the mounting bolt and tried to remove the support from the arm but it is holding fast. Looking at the parts breakdown there appears to be lock that are held in place by the mount bolt. How do I remove these or how do I pull this head so I can reverse it?

 

[wa5cab]

The lock in the M1-60 uses the same two locking bevelled cylinders as used to lock the tailstock ram. Remove the 1/4-20 nut and them remove the square head bolt. Flood the through-hole with penetrating oil and apply a little where the M1-9 Support Arm sticks through the M1-60. Let sit for several hours. Then use a split-type gear puller with nose-piece between the forcing screw and the end of the Arm. Torque up the forcing screw. If that doesn't move the M1-60, try a dead blow hammer or regular hammer and hardwood block against the head of the forcing screw.

 

[Airpirate]

Thanks for the answer, I already have removed the nut and bolt and have soaked the area with penentrant.

 

[wa5cab]

OK.

 

[Airpirate]

Rapped it with a piece of oak and it worked off with out too much effort. Thanks again for the tip.

 

[wa5cab]

OK. Good luck with the rest of it.

 

[Airpirate]

I have a few cutters for this machine they all are about 2.5" or smaller. Im looking at buying a side mill cutter, the distance between the arbor and support arm looks like it would accomodate larger diameter cutters. Is there a recommended max dia. For this machine? Is a staggered tooth side mill cutter more desirable than a straight cutter for general use?

 

[wa5cab]

I just went through the manual again, and found that cutter diameter is only mentioned in two places. One place is in the section telling how to calculte or select cutting speed. The other is where it says "Always use the smallest cutter that will do the job.". Nowhere does it state what the maximum allowable cutter diameter is.

 

[VSAncona]

I believe 4" is the maximum diameter that will fit under the overarm. I might use a thin slitting saw that large, but for milling cutters, I would stick with 3" or less.

 

[wa5cab]

That's correct. From the drawings of the M1-8 and M1-60 Arbor Supports, the distance from the C/L of the arbor to the bottom of the Overarm is 2.125". So the theoretical zero clearance spindle swing would be 4.250". So with a little clearance, you could swing a 4.000" diameter cutter or tool if you had to. However, the larger the diameter, the slower the spindle speed must be and the greater the available torque must be. So I would standardize on no larger than 3" and probably 2.5".