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Could Be A Dumb Rt Question
- Thread starter dlane
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4GSR
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My Imperial RT has a adjustable pointer that allows you to line up with the lines on the edge of the RT. And yes, I believe the slots have some sort of orientation with 12 o'clock position or was that 9 o'clock position. On the veriner, the dial is adjustable to zero, too. Any other brand I'm not sure on.
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Maybe scribe a new line where you want. Or just move the pointer. On my Vertex the pointer is in a useless location on the back when vertical the way I want to use it. I never really noticed if the 0 lines up with anything.
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BRIAN
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I came across this problem when making the jigs for my five cylinder radial engine project.
I think a problem comes when you turn the item over on the jig to machine the other side,. when the error to the right of the fiducial mark becomes an error to the left. and double the amount.
I corrected mine and put a new mark 90° further on that was visible when the RT is vertical.
Having set the Vernier I will not tamper with it untill the engine is finished .
One point to remember is to always approach the mark in the same direction of rotation to insure any slack is always on the same side
Brian.
I think a problem comes when you turn the item over on the jig to machine the other side,. when the error to the right of the fiducial mark becomes an error to the left. and double the amount.
I corrected mine and put a new mark 90° further on that was visible when the RT is vertical.
Having set the Vernier I will not tamper with it untill the engine is finished .
One point to remember is to always approach the mark in the same direction of rotation to insure any slack is always on the same side
Brian.
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Bill Gruby
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Most Rotary Tables can be reset by disengaging the worm from the wheel. I wonder though, why all of you think the slot position is that important? 0 is 0 no matter where the slots are positioned.
"Billy G"
"Billy G"
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I was thinking this myself but, with different manufacturers, perhaps his doesn't disengage?
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My 12" Enco table has Tee slots parallel to the vertical base.
The 6" Tormach, which appears to be a Phase II clone, is at 20* when the slots are parallel to the vertical base. The degree scale in engraved into the table so it can't be adjusted relative to the Tee slots. Jumping a tooth on the worm will not change it.
Looking at the table construction, it appears that there was a design failure when designing the casting as there is a rib which would possibly interfere with milling the flat for the index plate so they just shifted the flat by 20*. That leaves moving the index mark if you want to shift where 0* lines up.
As I looked at mine, I think that I could mill a second flat and drill and tap the hole for the index plate mounting screw. It is not important to me since mine is motorized and has a DRO.
When using the Enco table, I would make up a table of the angles that I needed to machine at since it is difficult to line up a workpiece precisely parallel to the RT ways. e.g., if I were machining something with five-fold symmetry, my angles would be multiples of 72*. If my offset is 4* 30', I would add that to the desired angle to get the machining positions so 72* becomes 76*30', etc.
I find that the table index mark doesn't have to be precise because on a 90:1 table, the dial on the worm repeats every 4* ant the dial is what I use to set my angle. The table index mark just gets me in the ballpark so ,in the above example, as long as the index is more than 75* and less than 78*, I'm good. I do have to pay attention to where on the dial I am, however.
The 6" Tormach, which appears to be a Phase II clone, is at 20* when the slots are parallel to the vertical base. The degree scale in engraved into the table so it can't be adjusted relative to the Tee slots. Jumping a tooth on the worm will not change it.
Looking at the table construction, it appears that there was a design failure when designing the casting as there is a rib which would possibly interfere with milling the flat for the index plate so they just shifted the flat by 20*. That leaves moving the index mark if you want to shift where 0* lines up.
As I looked at mine, I think that I could mill a second flat and drill and tap the hole for the index plate mounting screw. It is not important to me since mine is motorized and has a DRO.
When using the Enco table, I would make up a table of the angles that I needed to machine at since it is difficult to line up a workpiece precisely parallel to the RT ways. e.g., if I were machining something with five-fold symmetry, my angles would be multiples of 72*. If my offset is 4* 30', I would add that to the desired angle to get the machining positions so 72* becomes 76*30', etc.
I find that the table index mark doesn't have to be precise because on a 90:1 table, the dial on the worm repeats every 4* ant the dial is what I use to set my angle. The table index mark just gets me in the ballpark so ,in the above example, as long as the index is more than 75* and less than 78*, I'm good. I do have to pay attention to where on the dial I am, however.