How do I remove these gears and shaft from apron?

[DrReid]

Greetings. Need basic help, please. I've disassembled all but one part of my Mori Seiki MS850 apron. Inexperience stops me short of going full gorilla on shaft 43 and two gears 41 and 45 held thereto in the attached diagram. I've already removed grub screw 42 from gear 41. Gear 45 is held to shaft 43 by a few roll pins on the 'rear' (bed) side, as I've shown in the attached photos. Shaft 43 extends through and rotates in the apron body.

How do I remove the gears and shaft? It appears that I could tap shaft 43 through gear 41 toward the rear side of the apron and thereby remove 43/45 as one piece. Should I press it out instead? I'm a little gun-shy because a screwup here would make this subassembly damaged and/or very hard to remove.

 

[MikeWi]

seems like the only way to do it.

 

[piper184]

if the set screw was against the shaft there may be a burr on the shaft. If the screw was contacting the key it should come out fairly easy.

I would go for it using the largest diameter punch that will still be smaller than the shaft.

The shaft rotates in the housing on the small gear side, right?

 

[DrReid]

if the set screw was against the shaft there may be a burr on the shaft. If the screw was contacting the key it should come out fairly easy.

I would go for it using the largest diameter punch that will still be smaller than the shaft.

The shaft rotates in the housing on the small gear side, right?

I cannot tell what the set screw is against: I rotated the gears/shaft to be positioned exactly as shown in the diagram, which appears to indicate the (very short) set screw against the key. FWIW, the set screw is a small standard head, possibly indicating low torque. (I removed it with mercifully little effort.)

And, yes, the shaft rotates freely in the housing on small gear (41) side.

Use a brass rod/drift with D< shaft D? (I don't want to mar the shaft, unless a steel punch is warranted.)

 

[piper184]

It shouldn't be stuck too hard. Lots of little taps rather than big blows. A dead blow hammer to minimize bounce of the punch on the shaft.

Is there any detectable end play of the shaft? I would think there is at least some clearance.

I wonder what sets the backlash between #45 and #46?

 

[DrReid]

It shouldn't be stuck too hard. Lots of little taps rather than big blows. A dead blow hammer to minimize bounce of the punch on the shaft.

Is there any detectable end play of the shaft? I would think there is at least some clearance.

I wonder what sets the backlash between #45 and #46?

Thank you kindly for your guidance.

Yes, I can just move shaft 43 in/out (longitudinally) maybe a thou or two. Barely perceptible by hand, but its there.

Gear 46 is moreover held in place by a bushing (two halves of a 'clamshell') that is bolted to the rear surface of the apron. Hence, I suppose the height of the bushing establishes relative position and, hence, degree of engagement between, gears 45 and 46. I'm clawing my way up a learning curve, so let me know if my answer strayed off target.

 

[piper184]

I think you are on the right track. Since you know there is a little end play, you have a reference point for progress.
With any kind of luck the gear is just stuck a little and you can tap the shaft out easily.
Let us know how it goes.

 

[piper184]

In the picture of the small gear with the set screw removed, is the boss behind the gear part of the casting or are we looking at the back side of the larger #45 gear?

The reason I ask is if that is part of the casting, the key in the shaft may be trapped in the pocket cut into the shaft. IF that is the case, you may not be able to move the shaft any farther than the distance from the end of the key to the boss. So if tapping the shaft gets it to move, then it seems to "bottom out", don't force it.

If what we see in the picture is the back side of the #45 gear, the whole thing should just come out towards the large gear side. This is starting to look like one of those Chinese puzzle boxes. Unless I am just over-thinking it.

It makes me wonder if there is some hidden retainer under the large #45 gear?

Do you have a parts drawing of the housing these parts fit into? If so, please post it. Or a picture of the gear and housing, not zoomed in so close?

 

[DrReid]

Several gentle taps on the shaft with Mr. Slammy removed shaft and gear 45 very smoothly. No Chinese puzzle.

Yes, I have exploded parts diagrams, but they show only all gears in one, and only the front side of the apron in the other. And the diagrams are slightly different than my apron, possibly because of year mismatch. In any case, I proceeded cautiously at first and then I the shaft was out in seconds.

Thanks so much for very quick help. I’m adding knowledge and confidence with each step in my rebuild.

 

[piper184]

Good deal!
I was having a hard time visualizing how that key could come out when the slot didn't go all the way to the end. Now I see the bearing journal on the large gear end is larger than the stick-out of the key when it is in the shaft.

Well done.