This is my 6" HV RT Dividing Plate Rant.......

[YYCHM]

So, I acquired a 6" HV RT which is basically this one sans TS and dividing plates.

Buy Rotary Table 6in. C/w Tail Stock/indexing at Busy Bee Tools

6" Rotary Table, Horizontal/Vertical Fine grade cast iron Precision ground hardened worm Ratio: 90:1 360degree graduations Comes with Index Plates and Tail Stock

www.busybeetools.com

Then I order a dividing plate kit from Amazon https://www.amazon.ca/gp/product/B01N249BVJ/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

These are the fails.....

With the crank handle removed the plate should simply mount on this back plate which it does. Note the groove on the shaft. That groove needs to be exposed with the plate and sector arm installed in order to accept the sector arm retaining spring.

The first thing discovered is that the crank handle assembly is way too long with a plate installed and the spring in the plunger assy is brutally strong

Next thing discovered was that with the sector arm installed, the groove for the sector arm retaining spring wasn't exposed

The third thing discovered was that the sector arm wouldn't allow the crank handle plunger pin to engage the plate holes on the two inner hole patterns

And lastly the shaft where the crank handle mounts extends past the crank so you can't retain it with the washer and screw that came with the RT

Will present my fixes in another post, but this is how it came together out of the box.... Not Happy.

@140mower , @David_R8 Have you tried mounting your dividing plates yet?

 

[Susquatch]

You sound pissed off. You ok there?

At the risk of starting another indexing plate debate, I think they are over-rated. You can prolly do everything you need to without them.

But I'm gunna figure out how to add them to my RT too...... LOL!

Keep us informed.

 

[YYCHM]

You sound pissed off. You ok there?

At the risk of starting another indexing plate debate, I think they are over-rated. You can prolly do everything you need to without them.

But I'm gunna figure out how to add them to my RT too...... LOL!

Keep us informed.

Ya, I'm over it now, but it took a full day to fix things before I could use it.

 

[Dusty]

So, I acquired a 6" HV RT which is basically this one sans TS and dividing plates.

Buy Rotary Table 6in. C/w Tail Stock/indexing at Busy Bee Tools

6" Rotary Table, Horizontal/Vertical Fine grade cast iron Precision ground hardened worm Ratio: 90:1 360degree graduations Comes with Index Plates and Tail Stock

www.busybeetools.com

Then I order a dividing pate kit from Amazon https://www.amazon.ca/gp/product/B01N249BVJ/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

These are the fails.....

View attachment 18448

With the crank handle remove the plate should simply mount on this back plate which it does. Note the groove on the shaft. That groove needs to be exposed with the plate and sector arm installed to in order to accept the sector arm retaining spring.

View attachment 18449

The first thing discovered is that the crank handle assembly was way too long with a plate installed and the spring in the plunger assy is brutally strong

View attachment 18450

Next thing discovered was that with the sector arm installed the groove for the sector arm retaining spring wasn't exposed

View attachment 18452

The third thing discovered was that the sector arm wouldn't allow the crank handle plunger pin to engage the plate holes on the two inner hole patterns

View attachment 18451

And lastly the shaft where the crank handle mounts extends past the crank so you can't retain it with the washer and screw that came with the RT

Will present my fixes in another post, but this is how it came together out of the box.... Not Happy.

Hey Craig, I don't blame you for being annoyed after laying out good money and product like this turns sour. From what I understand there's no real standards when it comes to buying dividing plate sets. Sort of pot luck or a pig in a poke. Not what you wanted to hear good buddy however, knowing your skill level I'm confident things will work out just fine. Stick with it.

 

[YYCHM]

Hey Craig, I don't blame you for being annoyed after laying out good money and product like this turns sour. From what I understand there's no real standards when it comes to buying dividing plate sets. Sort of pot luck or a pig in a poke. Not what you wanted to hear good buddy however, knowing your skill level I'm confident things will work out just fine. Stick with it.

It's all fixed up now and I used it to cut a gear already, so ya it works but still....

I suppose what this really means is that if you get a RT you had best get the plates and accessories from the same vendor.

 

[Dusty]

It's all fixed up now and I used it to cut a gear already, so ya it works but still....

Hey Craig, I hear you enough to hiss off a snake.

 

[YYCHM]

Here are my fixes........

From left to right.

1. Remove the RT back plate and make a ultra thin back plate. That placed the crank handle pin where it should be.

2. Make a bushing to sit on top of the sector arm so that the sector arm retaining spring could be installed.

3. Mill some relief on the sector arm such that the positioning pin can be located. Still not great for the inner circle holes.

4. Make a recessed crank mounting washer.

This is with every thing installed. The crank handle doesn't cant like the image shows, that's a photo illusion.

Of interest here is that I tried installing a washer behind the crank handle that butted up to that threaded and set screwed collar behind it. That seemed to bind the table up for some reason, and when you have to crank N full turns and then some, X times, you don't want to be fighting the RT or positioning pin placement (heavy plunger spring).

It worked in the end, but, seriously, I shouldn't have had to jump through those hoops with something advertised as suitable for a 6" RT.

RANT over!

 

[Susquatch]

Here are my fixes........

View attachment 18461

From left to right.

1. Remove the RT back plate and make a ultra thin back plate. That placed the crank handle pin where it should be.

2. Make a bushing to sit on top of the sector arm so that the sector arm retaining spring could be installed.

3. Mill some relief on the sector arm such that the positioning pin can be located. Still not great for the inner circle holes.

4. Make a recessed crank mounting washer.

View attachment 18462

This is with every thing installed. The crank handle doesn't cant like the image shows, that's a photo illusion.

Of interest here is that I tried installing a washer behind the crank handle that butted up to that threaded and set screwed collar behind it. That seemed to bind the table up for some reason, and when you have to crank N full turns and then some, X times, you don't want to be fighting the RT or positioning pin placement (heavy plunger spring).

It worked in the end, but, seriously, I shouldn't have had to jump through those hoops with something advertised as suitable for a 6" RT.

RANT over!

Great work @YYCHM !

You caught me before I asked what the bent handle was all about. I tried but failed to visualize how that could happen. The best I could do was to imagine it straight but the disk beside it crooked.

Can you not cut a relief angle on the top plate/washer to allow the handle pin to reach the inner ring of index points?

 

[6.5 Fan]

I thought the bent handle was from chucking said unit across the shop on to a concrete floor. Then i read that it was an optical illusion. Good fix to make things work properly.

 

[johnnielsen]

The upside is you figured out what needed to be done and did it with your machine tools. Well done.

 

[DavidR8]

So, I acquired a 6" HV RT which is basically this one sans TS and dividing plates.

Buy Rotary Table 6in. C/w Tail Stock/indexing at Busy Bee Tools

6" Rotary Table, Horizontal/Vertical Fine grade cast iron Precision ground hardened worm Ratio: 90:1 360degree graduations Comes with Index Plates and Tail Stock

www.busybeetools.com

Then I order a dividing plate kit from Amazon https://www.amazon.ca/gp/product/B01N249BVJ/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

These are the fails.....

View attachment 18448

With the crank handle removed the plate should simply mount on this back plate which it does. Note the groove on the shaft. That groove needs to be exposed with the plate and sector arm installed in order to accept the sector arm retaining spring.

View attachment 18449

The first thing discovered is that the crank handle assembly is way too long with a plate installed and the spring in the plunger assy is brutally strong

View attachment 18450

Next thing discovered was that with the sector arm installed, the groove for the sector arm retaining spring wasn't exposed

View attachment 18452

The third thing discovered was that the sector arm wouldn't allow the crank handle plunger pin to engage the plate holes on the two inner hole patterns

View attachment 18451

And lastly the shaft where the crank handle mounts extends past the crank so you can't retain it with the washer and screw that came with the RT

Will present my fixes in another post, but this is how it came together out of the box.... Not Happy.

@140mower , @David_R8 Have you tried mounting your dividing plates yet?

My indexing setup fit perfectly but I also bought it all from the same eBay vendor. Oddly it was cheaper to buy the table and footstock together and the indexing plates separately. No idea why.
Sorry for the thread revival....

 

[Former Member]

You sound pissed off. You ok there?

At the risk of starting another indexing plate debate, I think they are over-rated. You can prolly do everything you need to without them.

But I'm gunna figure out how to add them to my RT too...... LOL!

Keep us informed.

Well since I only found this thread now and you did open the door.....

Do you need indexing plates, No.

Should you use them, Yes, as they provide equal spacing far more accurately than you can do manually when required.

Finally the only time you rely don't need them is when you've gone CNC (but for some of you, enough said).

 

[Susquatch]

Should you use them, Yes, as they provide equal spacing far more accurately than you can do manually when required.

Well, that's the debate I referred to above.

I don't think they do. Too many errors in the plate backlash, index pin placement, and strain in the mechanism vs Vernier based manual adjustment to a higher precision than possible with the index plate system.

Of course, it can be argued that manual repetition leads to a lapse in attention and human errors in both the math and the settings that is avoided with the plates.

But in terms of pure accuracy and precision, I believe that the manual system is superior.

 

[Former Member]

For a one or two maybe, for multiple repeats not so.

The errors in backlash whether plates or manual is identical and as long as you follow good practices to work in one direction both are nearly eliminated. If the same fínese is used to set the vernier is applied to the pins the same (or better) repeatability occurs. So two of your three points are solved easily.

As to pin placement well if you are worried about messing this up, good luck in getting your math and readings correct. So this is mute point.

Rough quick one to angles maybe go manual, cut a gear set, plates are the only way to index.

While I say this I have looked at various rotary tables and found that they all have a fair bit of backlash so even with CNC unless you are paying mega $ you need to consider good old school practices in your approach one direction of rotation to ensure backlash doesn't occure.

Funny enough I would have expect that you knew this.

 

[Susquatch]

For a one or two maybe, for multiple repeats not so.

We will have to agree to disagree.

The errors in backlash whether plates or manual is identical and as long as you follow good practices to work i one direct both are nearly eliminated.

Not really. The plates, crank, arm and pin add another level of inferred displacement based on a gear system with parts that are stressed and can flex. The table and Vernier system are a direct readout of the table rotation itself. There is nothing to flex or bend. It simply is what it is.

If the same fínese is used to set the vernier is applied to the pins the same repeatability occurs. So two of your three points are solved easily.

Nope - adjusting the plate via its Vernier and scale is more accurate than using the plates. That's the whole point of the discussion you joined.

As to pin placement well if you are worried about messing this up, good luck in getting your math and readings correct. So this is mute point.

Didn't say anything about pin placement getting messed up. In fact didn't say there was anything wrong with using the plates or pins. Only said that the Vernier system was more accurate. The more important question is, does the difference matter? Personally, I don't think it does. I only disagree when someone else says that the plate system is more accurate.

Rough quick one to angles maybe go manual, cut a gear set, plates are the only way to index.

Didn't say they were not. Just that a manual adjustment is more accurate.

While I say this I have looked at various rotary tables and found that they all have a fair bit of backlash

The crank system has backlash, but the table Vernier Readout does not. It is a Readout of the table's actual position. So if the table position system is used to position the table, backlash is not a factor. The same cannot be said for the plate system.

so even with CNC unless you are paying mega $ you need to consider good old school practices in your approach one direction of rotation to ensure backlash doesn't occure.

Not talking normal backlash. Specifically talking backlash in the plate system which is additive to the table crank. This becomes especially true as the pins are wiggled into the index hole which has a level of hysteresis and pin arm flex that does not exist in the direct table position measurement system. The table indicator system is part of the table itself and therefore is a true reading not an inferred reading like the crank and plates.

Funny enough I would have expect that you knew this.

Really Degen?

 

[Former Member]

Well what little I was was taught by my grandfather a true Master in Precision Tool and Die from Austria, he would tell you differently.

 

[Susquatch]

Well what little I was was taught by my grandfather a true Master in Precision Tool and Die from Austria, he would tell you differently.

Crap. That means I have to agree to disagree with both of you!

 

[Former Member]

I guess that explains why cars have the problems that they do .

 

[Susquatch]

Be nice.

 

[Dabbler]

I normally stay away from discussions like this.

Firstly, because I love the English language - it is a "moot point " not a "mute point"

CNC bashing is unnecessary as you get the accuracy you pay for in CNC. The ones I'm familiar with are accurate to 5 arc seconds or so. That is nearly undetectable from wobble in an end mill or a centre deviation.

Remember our context is a 6" hobby rotary table here. If your are going for a small number of divisions, say 6 or 10 or 12, then it is faster and just as, and perhaps even more, accurate to use your vernier and direct indexing. It is far harder to mess up.

A rotary table uses a 40:1 gear ratio on the worm gear. Most of your indexing errors will come from improper fit of the worm gear. If you want *really* accurate indexing, that is what the dividing head is for. They typically use a 90:1 gear ratio with a much better ground gear and worm. Using the sector arms eliminates almost all of the indexing problems, unless you cannot count revolutions or you are sloppy.

For many divisions, such as making a 127 gear for a lathe, then using a rotary table or dividing head with the plates is a practical necessity.

----

BUT here is the caveat: cheap offshore worms are often not precision ground, and you won't get European Old School accuracy out of the 6" rotary table. If you are sly enough to get a German made Brown and Sharpe 8" rotary table made before WW2, then you have an accurate device. But there have been a lot of apples vs oranges comparisons here,