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9" SM Utilathe Restoration

My Tiwaneses 1340 works exactly the same. Probably a gear positioning issue that the first inventor of internal power cross feed saddle mechanismns overcame and everybody else can't come up with a more simple cost effective method so they just fallow suit.
 
YYCHobbyMachinist said:
Is this behavior correct? Is something installed backwards?
Click to expand...

I can’t remember 100%, but I think my 9” Utilathe was like that.

My guess it has to do with space availability in the apron. In order to have the cross slide feed in toward the center, you would need another gear to change the direction.

Both the SM 1120 and the SM 1340 (and the Colchester) traverse in while feeding toward the headstock; they have much larger aprons compared to the 9” Utilathe though.
 
The 1020 also feeds in for power cross feed and the apron advances towards the head stock when in forward mode. The 9 inch uses its lead screw as the feed drive as well and the lead screw has a longitudinal key way that turns a worm drive on the back of the apron just before the half nuts. This worm drive (keyed to the lead screw) rotates the gears in the apron that advance the apron or the cross feed. I think there is just the feed clutch mechanism gears between the cross feed gear and the worm drive where there are two more gears involved in the longitudinal feed.
 
I think it varies by lathe. On my 14x40, the carriage traverses R>L with shifter UP+LEFT in normal forward spindle direction. If I move shifter DOWN+RIGHT, the crossfeed engages from operator to rear of lathe direction. I also have a knob on the headstock that switches carriage direction from R>L and L>R so the above is reversed. And another knob that switches from powerfeed to threading engagement. So the combination of knobs & shifter allows pretty much any permutation. But when I was fiddling around on another 14x40, the default directions & controls were slightly different. If I ever switch lathes I will have to get electroshock therapy to cleanse my brain from hardwired habits.
 
KEY.JPG


Today's project was a chuck key to replace the bent key that came with my lathe.

How do you bend something like that??? The flats are 0.4" wide! Would need access to a press to straighten if it can be straightened at all.

Was a fun afternoon of sawing, turning, milling, drilling and tapping.
 
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Yup, what John said. Which is just one Darwin move better than having it launch it out of the chuck on startup... through the wall, your skull... etc.
That's why new keys typically have a spring on them as a physical feedback, they cant stay in. I hate them myself & remove them. But we have to play safe with our toys.
 
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When I made some keys I threaded the end of the boss so I could locate the tommy bar mid way & it stays put. But I also like the sliding feature. You can still position mid way but also extend the handle for leverage or work around obstructions. I'm thinking of machining a groove in the ends for a O-ring so the bar cant drop out, but easy to remove etc
 

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The tommy bar on my key is held in place with a hex head grub screw. Your 0-Ring idea has given me an idea that might resolve an issue I have with vise tommy bars on my mini-mill...…. Thanks!
 
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The manual for my lathe states:

Spindle nose taper No. 3M
Spindle center No. 2M

What does that mean? What taper should I get for my spindle?
 
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My Amazon ordered 2.5X45 tap and drill bit arrived (needed to mound the carbide insert tool) and with a few days off I finally got a chance to finish and try my ball turning attachment.

XSLIDE.JPG


The attachment replaces the compound rest and mounts on the x-slide via this arrangement

BOTandTop.JPG


The base is on the left and the turret (for lack of a better word) is on the right. Tool post is in the middle. 3/8" carriage bolt for a handle. The base and turret were made from 3" steel round stock I had left from making my monolithic tool post.

INTERFACE.JPG


The interface between the base and turret is pretty simple. I need to remember to grease it when I re-assemble.

RAWSTOCK.JPG


My tool post is only 0.75" high so here I had to turn down a piece of 1.5" aluminium round stock to 1.25".
The round stock was drilled and tapped for 3/8" and mounted on a bolt stub.

EGE.JPG


First go produced a bit of an egg, not real bad but an egg never the less. Finish is terrible. I think that carbide inserts is just a little too pointy for aluminium? The stick out on the 3/8" bolt stub probably didn't help matters either.

BETTER.JPG


I managed to make her a little more round by adjusting the tool post.

I'm pretty please with how this project turned out. I should replace the handle with something more eloquent and try turning some steel next.

Cheers
 
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Round shiny balls, here we come! LOL

I cant quite see how your handle is orientated but just make sure - you don't want to be rotating in close proximity to chuck jaws. So go through the motion range before commencing cutting. Even so, I can see where the rotation might be progressively increasing a bit with each pass as the ball forms more completely on the head stock side & this may vary by diameter & chuck stickout.
 
How much head stock gear back lash is considered acceptable? I've noticed some back lash between the pulley shaft and main spindle when in high range. It's there, I can feel it and I can see it occurring between the spindle gear and the a gear on the pinion shaft. How does one measure it? I don't perceive any back lash in low range.

Thanks.
 
Well, there will always be some backlash in gearing for clearance to run and all that fun stuff. Your Lathe has basically two sets of gear ranges - the high range and low speed range and then pulley changes to get different speeds within the high or low selection. Probably, there will be more wear in the range the lathe was/is mostly used in. The "more wear" will show as an increase in backlash, That being said, once the lathe is running and the gears are meshing wear will typically appear as noise. hard to say what would be the noise level of a "new" machine.
 
Backlash isn't a factor in the gear train, as long as you are aligned properly, and there is not ongoing wear of the gears. Even in the QCGB, the threads and feeds are not affected by backlash concerns.
 
Todays project was to install the spring tensioned motor mount that came on the parts machine BrentH and I scored.

tensioner.JPG


The mount that came with my machine didn't have the tensioner depicted here and relied on the motor weight to tension the v-belt. I've noticed that the motor bounces a little when stopping my big 4 jaw chuck so I thought the tensioner might prevent that. It helps but hasn't eliminated the bounce. Note that pipe in the chip tray. I now have to use that as a snipe in order to lift the motor for belt position changes.

motor.JPG


Dismounting and mounting the motor from the front with the head stock in place wasn't fun at all:(. In the end I got her done with minimal cursing.

ESD.JPG


While I was at it, I re-positioned the ESD switch to the front of the lathe per johnwa's suggestion. It was previously mounted above the head stock beside the fwd/rev switch and required reaching over the machine to hit it. Thanks for pointing that safety flaw out John.
 
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