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Atlas MF Backgear locks spindle
- Thread starter vtcnc
- Start date
- Joined
- Jul 8, 2018
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- 880
No plan was ever made worse by adding a laser!
- Joined
- Dec 25, 2011
- Messages
- 10,516
The mill direct drive pin and detent is different on the mill from what it is on the 10" and 12" lathes. On the three model groups of lathes, the hole from the outside is deeper and not threaded. The spring goes into the hole first, followed by a ball-nose pin. A tool is inserted into the hole to press the pin down, compressing the spring. The direct drive pin is inserted in the hole while inverted, the tool is jerked out while pushing on the direct drive pin. Then with the direct drive pin in the direct drive orientation, the direct drive pin is rotated 180 degrees, allowing the ball-nosed pin to seat into one of the detent holes.
On the mill, everything is inverted. To assemble it, one would first insert the direct drive pin into the hole for it in the face of the gear, pushing it on into the mating hole in the face of the pulley. Instead of a ball-nosed pin, it uses a ball. The ball is dropped into the tapped hole in the gear, followed by the spring, followed by the screw. So what I would suggest that you do if the direct drive pin doesn't move freely using the tool that you made. If it does, of course, you don't need to do anything else other than engage Back Gear.
If not, first remove the set screw. Then use a small hook to remove the spring. And finally a magnet to remove the ball. If the direct drive pin still doesn't move, fill the hole with penetrating oil and try it again tomorrow.
On the mill, everything is inverted. To assemble it, one would first insert the direct drive pin into the hole for it in the face of the gear, pushing it on into the mating hole in the face of the pulley. Instead of a ball-nosed pin, it uses a ball. The ball is dropped into the tapped hole in the gear, followed by the spring, followed by the screw. So what I would suggest that you do if the direct drive pin doesn't move freely using the tool that you made. If it does, of course, you don't need to do anything else other than engage Back Gear.
If not, first remove the set screw. Then use a small hook to remove the spring. And finally a magnet to remove the ball. If the direct drive pin still doesn't move, fill the hole with penetrating oil and try it again tomorrow.
- Joined
- Jun 29, 2014
- Messages
- 4,061
This appears to be the setup I have. I'm not inclined to try and remove anything from the gear as I fear it will fall into the belly of the beast and I'd rather cut chips than dissassemble the back of the base and fish around with a magnet for a spring and ball.
Plus, I'm not so sure those are even in there. When I tried my wrench out, the pin was locked in place. Upon further inspection, a setscrew was drilled and tapped radially towards the pin. When I backed off the set screw, the pin freely moved with the wrench with a little resistance from what I would chalk up to excess grime.
Backed the pin out so it doesn't collide with the casting, rotate the spindle to test for that and then lock the pin with the setscrew.
Backgear works!
Thanks for your help guys.