Atlas 6 MK2 direct drive won't stay engaged

That idler pulley can be a pain- mine was chattering and wobbling around so I finally got fed up and bored it out and installed
a needle bearing in there, and replaced the shaft with a piece of hardened steel- problem solved

I don't know why the factory didn't put a knurl on the outside of the collar/coupler - it's hard to pull sometimes with greasy hands
Otherwise I like the ease of backgear operation, it's very quick to engage and disengage
 
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I had this same problem with the exact same mechanism when I first got my lathe..... At first, I removed the circlip and made a spacer to keep the drive teeth engaged, then I quickly realized that the mechanism has to operate in both the engaged and disengaged positions for speed selection so I removed the spacer.

. I inspected the part and it had a drilling across the diameter that held a spring and ball on one side of the part. That "sprung ball" fits into a depression on the shaft of the spindle to act as a detent to hold the engagement in place.

My solution was to clean the groove in the spindle, and then drill a slightly larger hole 98% of the way down toward the center of the part on the side without the spring and ball without going through the middle so a second ball would go down the hole and stick out opposite of the one that was already there, (and into the spindle groove) but wouldn't fall out of the hole because of the un-drilled end captured the larger diameter ball. I then found a correct size metal ball (from inside a fishing lure) and a good tiny spring put them down the hole from the outside and threaded the outside of the hole for a set screw to tension the spring and ball into the groove once installed on the spindle.... Fixed...

The addition created a little more detent pressure in the spindle groove by adding the second sprung ball opposite the first one and it never pops out now..... I suppose if I didn't explain it clearly, I need to take a picture.... just ask...
 
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o0norton0o said:
I had this same problem with the exact same mechanism when I first got my lathe..... At first, I removed the circlip and made a spacer to keep the drive teeth engaged, then I quickly realized that the mechanism has to operate in both the engaged and disengaged positions for speed selection so I removed the spacer.

. I inspected the part and it had a drilling across the diameter that held a spring and ball on one side of the part. That "sprung ball" fits into a depression on the shaft of the spindle to act as a detent to hold the engagement in place.

My solution was to clean the groove in the spindle, and then drill a slightly larger hole 98% of the way down toward the center of the part on the side without the spring and ball without going through the middle so a second ball would go down the hole and stick out opposite of the one that was already there, (and into the spindle groove) but wouldn't fall out of the hole because of the un-drilled end captured the larger diameter ball. I then found a correct size metal ball (from inside a fishing lure) and a good tiny spring put them down the hole from the outside and threaded the outside of the hole for a set screw to tension the spring and ball into the groove once installed on the spindle.... Fixed...

The addition created a little more detent pressure in the spindle groove by adding the second sprung ball opposite the first one and it never pops out now..... I suppose if I didn't explain it clearly, I need to take a picture.... just ask...
Click to expand...
This is a great solution! Thanks
 
Use a stop collar on the drill bit when you drill the hole. If you drill all the way through then the ball might keep falling out before you get the assembly on the spindle shaft. Of course, if you do drill all the way through it will still work but you just slide the ball and spring into the assembly after the engagement mechanism is on the spindle, and the spindle blocks the hole and keeps the ball from falling out. Thread in the set screw and finish assembling.... You're welcome, I hope it works for you.
 
Great advice. Mine already has one ball and spring mechanism. Adding a second one like you're suggesting will be perfect. Thanks
 
I wouldn't recommend it as a permanent fix but a temporary fix would be to remove the spring, and set screw and re0place them with a much longer screw, tightened with the detent ball bottomed in the hole (engaged).
 
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