• Scam Alert. Members are reminded to NOT send money to buy anything. Don't buy things remote and have it shipped - go get it yourself, pay in person, and take your equipment with you. Scammers have burned people on this forum. Urgency, secrecy, excuses, selling for friend, newish members, FUD, are RED FLAGS. A video conference call is not adequate assurance. Face to face interactions are required. Please report suspicions to the forum admins. Stay Safe - anyone can get scammed.

Index plate .STL file wanted

Darren

Ultra Member
Premium Member
Does anyone have a .stl of an index plate for a BS-0 dividing head with 127 holes? I could really use one.
 
Yes, on the Bambu X1C. I can try to find the dimensions. The outer diameter is not really important. It can be 8" diameter or so. the inner diameter is 0.829, 0.218 thick. I can drill the three mounting holes off my existing plates. I dont know their circle diameter or size. Drilling them later would be simple enough.

Ideally a plate of 8" diameter with 45, 50, 60,70,80, and 127 patterns.
 
Last edited:
Yes, on the Bambu X1C. I can try to find the dimensions. The outer diameter is not really important. It can be 8" diameter or so. the inner diameter is 0.829, 0.218 thick. I can drill the three mounting holes off my existing plates. I dont know their circle diameter or size. Drilling them later would be simple enough.

Ideally a plate of 8" diameter with 45, 50, 60,70,80, and 127 patterns.
There are a couple of plates on Printables. Not sure if they're what you need.
 
There are a couple of plates on Printables. Not sure if they're what you need.
I've been looking all over the place and haven't found one. I haven't had the time to try to design my own yet. Surely I'm not the only one to need a 127 hole plate.
 
Just a quick yeggi search


 
If you end up needing something custom, let me know. I would start with CAD & provide an STL. Its a bit more convoluted the other way around.
 
Here is an openscad design your own. Interested to see how well this one works.
 
Does anyone have a .stl of an index plate for a BS-0 dividing head with 127 holes? I could really use one.
I'm no expert, but the maximum number of holes in the included plates is 49 according to the manual. Higher numbers of divisions use indirect indexing. Because of the 40:1 ratio of the worm gear, there are 40 divisions for each hole on the dividing plate. So a 16 hole plate can create up to 640 divisions by advancing a single hole at a time. Advancing 2 holes cuts that to 320 divisions. Advancing 5 holes gives 128 divisions (640/5).

Unfortunately, I don't know a solution for 127 holes.

BTW, I believe the holes in the factory plates are slightly tapered so that if there is any wear to the pin, it just sits deeper and thus 'slop' in the mechanism is minimized.

Craig
 
BTW, I believe the holes in the factory plates are slightly tapered so that if there is any wear to the pin, it just sits deeper and thus 'slop' in the mechanism is minimized.

Very interesting. The indexing plate system on my universal dividing head is so sloppy that I really don't think a taper would help it.

I want to believe that these systems are better than my assessment of them, but that's hard to realize. I always end up in the same place. The plates are mostly about making the user believe the accuracy is better than it really is. Flex in the arm, the pin slide, the pin fit (which your taper eliminates), and the gearing system all conspire to destroy it. But does it really? Without an accurate precise way to measure the actual output angle, we don't really know.

This is the primary reason I bought that optical indexer. I want to use it to develop a more accurate way to read the actual output angles so I can evaluate indexing systems like that objectively.

This comment here is not meant to discourage what anyone is doing. It's just an observation of mine that I'd like to keep alive until it is resolved.
 
127 is a prime number. It can't be indexed without direct indexing off a master, which I could also do, or by using 40 holes of a 127 hole plate per gear tooth. That's with a 40:1 dividing head, or 90/127 with a 90:1 rotary table. I would prefer to use a plate. If I can't find a 3d printed plate, I can make one with the bolt hole function on my mills DRO. 3d printing a plate would be the easiest way. Any errors are reduced by 40:1
 
127 is a prime number. It can't be indexed without direct indexing off a master, which I could also do, or by using 40 holes of a 127 hole plate per gear tooth.

127 is 2.8346 (2° 50' 5") degrees per tooth. The 5" is actually 4.724. That can be accommodated by correcting every 5 seconds back by 1 second.

The gear will never know the difference.
 
A while back, I bought a small rotary table with a micrometer adjustment for the angle. It was actually quite cool. I only wanted the 360 degree plate with markings. Another unfinished project. But a micrometer adjustment yields rotary adjustments plenty good enough for cutting a 127 tooth gear. Who cuts teeth closer than 1 thou anyway?
 
I want to believe that these systems are better than my assessment of them, but that's hard to realize. I always end up in the same place. The plates are mostly about making the user believe the accuracy is better than it really is. Flex in the arm, the pin slide, the pin fit (which your taper eliminates), and the gearing system all conspire to destroy it. But does it really? Without an accurate precise way to measure the actual output angle, we don't really know.

Agree. If the ancillary drive train is not as reliable, then a super precise hole plate to 0.0000000 degrees is of little value. Or worded another way, you have no hope of achieving that accuracy level if the position is also dictated by other variables which have less accuracy. Its the same principle when applied to collective tolerances - the worst offender is the one to pay attention to. Some people have a hate on for all parallel bars. But dig a bit deeper & usually the real issue is not about geometry or how they are measuring, its because the QC in India is not up to snuff so the results were garbage. A banana bar is about as useful as a banana straight edge or an 89-deg square or a surface plate with a 0.002" bowl or hill topography. So I don't think anyone is 'making the users believe' or at least they shouldn't be.

Indexing plates are more about convenience & productivity like any jig or fixture. Someone has presumably done the hard work behind the scenes to put a odd number of positions like 127 into a device so that everyone else downstream does not need to get deep into the weeds of incrementing oddball arc minutes seconds & very likely making errors there or at least adding a lot of time to the job. As @Darren mentions, the gear reduction helps disperse the plate error by that :1 ratio, so in this application works to our advantage (at the expense of lots of spinning & sectoring).

At the end of all this you have to ask yourself, now what. Say you are into position on XY basis to within a tenth. Is the pointy metal removal thing like a drill or endmill accurate to that same degree? Will the surface finish be to within that degree? Will the hole actually extend perpendicular to that degree through the target depth?

What IS kind of exciting is that modern CNC's (or 3DP in certain limited applications) that can reliably position to say within 0.001" opens up a whole world of useful things because its trivial to draw complicated objects in CAD which have orders of magnitude more precision behind the scenes, even though we could never hope to achieve that resolution in real life.
 
I have another 127 tooth gear I can direct index from by mounting both to a common mandrel. I just wanted an stl file for a plate.
 
I have another 127 tooth gear I can direct index from by mounting both to a common mandrel. I just wanted an stl file for a plate.

Spoil sport.......

I had read earlier you had that. It is a perfect solution. I was just hyjacking your post to air a pet pieve. Sorry about that.

I think @PeterT summed it all up quite nicely. In many ways, it's analogous to CNC vs turning leade screws with a handle. I have a bit of a fetish around understanding what you are really doing vs the perception.
 

perhaps there are others
 

OMG I have to stop now!!
You waskely wabbit, you done gone down the hole again...... :rolleyes:
 
Back
Top