[How-To] Rank beginner question on cutting gears

BS-0 came in. Oof! Heavy little box. Picked it up by the strapping which started slipping when I had it 3 feet of the ground. Quick scramble to avoid dropping it. Running out of space in the shop... Need more shelving. And clear surfaces...
 
Other side of box is damaged. Axle is sticking out of box. Protruding SHCS looks like it hit something hard like the ground.:( A couple of crushed corners on the box. FedEx (or someone else) probably dropped it. Took pictures and sent to eBay. How rugged are these things? Opened box to see the obvious load shift and internally crushed styrofoam. I haven't pulled everything out of the box yet, just because I am not sure I should.

What's the likelihood that this dividing head will function correctly with it's inherent precision? Is this a try it and see sort of thing, or just send it back, or something else? Advice sought.
 
Well took it out of the box. First contact with the seller wasn't that helpful. Inspect they said. As if I knew what I was doing!

First thing I notice is the backlash. It's about 0.45 degrees, or one hole on the 20 hole plate. If I understand how to figure this out, it is: 360/40 * 1/20 = 0.45 degrees. I don't know if this is typical, or not. (Damaged or not.) There's some obvious additional polishing needed, the handle does not adjust freely as the slot seems to be non-uniform width, or there's some burrs. That I expected. At least for several rotations of the worm, there doesn't seem to be any sticking - but I have not done a full 40 rotations.

The instructions say to reduce worm backlash one does the following
1. Loosen locking bolt and turn the stop screw so far until worm backlash is taken out.
2. Tighten locking bolt.
The worm backlash has been removed when no more play can be observed on the index head spindle.

Of course the terminology used does not match the parts list nomenclature. Why do manual writers do this? New users don't know the synonyms yet. Old users don't need the manual... The picture next to the text (page 3) is fuzzy. Found a long winded youtube video, think I know how to adjust it now. Just needed a clear picture.

Guess I'll be doing at least a partial tear down.
 
You only turn it one direction in use, so backlash is not an issue. That backlash sounds acceptable. The key thing to check is that nothing is bent and that everything moves freely.
 
Definitely a kit... But I somewhat expected that. Grit and whatnot everywhere.

Pulled the worm, and found strands of swarf still attached to the worm. It's near the end of the worm where the thread gets thin. There's burrs on the end of the worm thread as well. More like a manufacturing defect, I think rather than from taking a hit. I'll clean off the rest of the grease and check the worm carefully. If I roll the shaft on a surface plate would that be a good check for a bend? Looking for light under it?
PXL_20210121_184941275.jpg
The video I watched showed a lot of manufacturing grit. What I am seeing is similar. Grit in the threaded holes too. I will try to pull the main shaft to inspect the helical gear and shaft Besides that, not sure what else could go wrong, save for a housing micro-crack maybe? So far I see no evidence of that.

For all that, the worm did move freely. And the backlash adjustment did take up the backlash. Although I saw the eccentric in the video, I was still surprised at the movement when I adjusted it. I was able to take out practically all the backlash. And the worm did move freely both ways.

All in all, it's still a value for $222 delivered. A lot of machining. Some clean up required. Pity they needed to make it kiss the ground before I got it.
 
So this unit came with a 125 mm 3 Jaw chuck. The chuck was bolted on through the back of the back plate with what seemed like 35 mm long bolts, not sure why that was done. Took a while to get the chuck off since you had to hold it and balance it while unscrewing the bolts. Now I am looking at the back plate. It should unscrew, correct? So right hand screw? Since I can't remove the bolts because they foul the dividing plate, I placed a nut on one of them and hit it with a hammer, though a block of wood. The plate didn't move relative to the spindle. The spindle rotated in the housing, because the spindle clamp wasn't tight enough. I don't dare use the locating pin, since I don't want to bend any thing. In the picture I hit the left screw that is at 9 o'clock downward, that should loosen it I hope. Just use a bigger hammer?
PXL_20210121_204644154.jpg
I'm going from memory from what I have read here about making backing plates. Righty tighty, lefty loosey?

Once I get this further apart, I need to re-clock that spindle clamp since it fouls the index pin lever.
 
This is pretty typical quality from what I hear. I'd cobble together one of my own, but that's just me. The more projects the better.
 
I'm not terribly surprised having watched a few videos on these BS-0's. Have the backing plate off now. Now to pull the the spindle out. Need to make a pin spanner.
 
Rotary tables are mostly designed to divide by degrees, not tooth spaces, unless they have a dividing attachment ( a set of plates like a dividing head uses). Best to buy a dividing head, I think.
 
Tearing this unit down further revealed a cracked bearing housing. I requested and received a refund. It took a while, but finally received all my money back. The seller tried to lowball me several times, but I simply said this was received damaged, but I purchased a new (and undamaged) unit. After 5 days of haggling, I told them to stop delaying and to refund my money.

Have placed an order with PM for the same BS-0. I'm positive it will arrive in better shape. On the bright side, I can tear a BS-0 down pretty quickly. The first time around I had to make a pin spanner wrench to pull the bearings, hopefully I won't even need to use that tool. Hope to get back to trying out gear making... and probably a slew of questions.
 
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