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Newbie Question- Mounting Chuck To Rotary Table
- Thread starter WoodenFlutes
- Start date
Jay,
I don't know anything about Irish flutes, so this may not be applicable, but, it sounds like these parts could be very fragile/delicate, hence your desire for a six jaw chuck. Just to give you another option, you may consider using a 5C collet chuck rather than the six jaw. The 5C collets will hold delicate parts much better than the chuck. If the parts are larger in diameter than 1.125" (that's the largest standard 5C collet size), you can use a 5C step collet and machine it to the exact size needed for your parts. Also, if 5C collets would work for you, you may be able to use a 5C spin indexer in lieu of the rotary table. This would be a much less expensive option.
Just some food for thought.
Ted
Ted,
Good thoughts. The flute body might be made up of 3-5 sections, each fitting together with a tenon and socket. There are silver, D-profiled rings that stick up above the wood, to strengthen the sockets. These would not work with 5C collets, unfortunately. I wouldn't normally install the rings before milling the key blocks on a new flute. However, any repair work would necessitate removing the rings if all I had was a 5C setup, and that in itself could damage the flute. Rings are often installed with epoxy. With a chuck, just open it a bit wider and insert until the ring is just inside the jaws before clamping down on the flute body.
Thanks!
Jay
Good thoughts. The flute body might be made up of 3-5 sections, each fitting together with a tenon and socket. There are silver, D-profiled rings that stick up above the wood, to strengthen the sockets. These would not work with 5C collets, unfortunately. I wouldn't normally install the rings before milling the key blocks on a new flute. However, any repair work would necessitate removing the rings if all I had was a 5C setup, and that in itself could damage the flute. Rings are often installed with epoxy. With a chuck, just open it a bit wider and insert until the ring is just inside the jaws before clamping down on the flute body.
Thanks!
Jay
I've built a plate that fits my 4" RT and attaches with 6mm socket heads. My 6" lathe chuck attaches with socket heads from the back of the plate. In this case, the bolt pattern for the chuck was just big enough to cleat the RT.
I just went through a variation of this for more conventional (metalworking) application. here are some other considerations FWIW.
A plain back chuck that you would probably select for mounting to RT might come in 2 flavors: Front mount (bolts pass from jaw side through chuck body & then into adapter plate). And rear mount (the backside has tapped holes to receive bolts). Some chucks may even offer both. I would encourage you to carefully check the catalog & specs. Some offer front mount, but only within a certain range. For example FM for 6" & larger but then RM for 5" & lower. And from personal experience, sometimes the catalog posts a generic picture for the entire chuck range which can be misleading. So looks for the ** fine print or confirm with vendor.
Easiest apparent solution would be a FM chuck that bolts directly into the t-slots of RT with no inter-plate. But you need to confirm some things. A typical 3 jaw scroll chuck would have bolt holes further out on the periphery (to avoid the scroll) & would likely be 3 bolts (to be spaced between the jaws). I'm not sure what 6-jaws have. But my point is 3-pattern chuck bolts holes wont engage a 4-slot RT, but would fit a 3 or 6-slot RT. And obviously the bolt hole circle diameters must be accommodated. Personally I wouldn't choose a specific RT model solely based on chucks (unless you have an expensive one you want to utilize). Because there are many other RT specific purchase considerations.
Centering. If your woodworking application is not fretting about a few thou here then lucky you. For precision metalworking its often necessary to ensure chuck clamping is absolutely concentric with RT rotation axis. I've had pretty good luck with most jobs dropping an morse taper arbor into the RT, lightly closing the chuck jaws down on the extending stub, then clamping the chuck to RT into that position. But you can only do this with either a FM chuck or an inter-plate ie. an assembly that facilitates the chuck being able to float a bit & then clamped down. If OTOH the chuck is 'fixed' to the RT by some rear mount centering plate & no way to adjust it, that can introduce runout & you are stuck with this. So another option is get an independent jaw 4-jaw chuck which you can dial in to the work, same deal as a lathe setup. This also allows you to hold non-round work & offers 1 more jaw over a 3. But that takes more time to set up each job.
Other RT purchasing considerations. If you are holding things that require tailstock support in vertical mode, consider looking for brands that sell matched tailstocks. If you find yourself wanting to index to fixed divisions repetitively (as opposed to rotating or arriving at odd angular increments) then consider getting dividing plate set that might be offered with RT. Also, you may want to look at a dividing head which is a different animal but may offer some advantages over a RT.
A plain back chuck that you would probably select for mounting to RT might come in 2 flavors: Front mount (bolts pass from jaw side through chuck body & then into adapter plate). And rear mount (the backside has tapped holes to receive bolts). Some chucks may even offer both. I would encourage you to carefully check the catalog & specs. Some offer front mount, but only within a certain range. For example FM for 6" & larger but then RM for 5" & lower. And from personal experience, sometimes the catalog posts a generic picture for the entire chuck range which can be misleading. So looks for the ** fine print or confirm with vendor.
Easiest apparent solution would be a FM chuck that bolts directly into the t-slots of RT with no inter-plate. But you need to confirm some things. A typical 3 jaw scroll chuck would have bolt holes further out on the periphery (to avoid the scroll) & would likely be 3 bolts (to be spaced between the jaws). I'm not sure what 6-jaws have. But my point is 3-pattern chuck bolts holes wont engage a 4-slot RT, but would fit a 3 or 6-slot RT. And obviously the bolt hole circle diameters must be accommodated. Personally I wouldn't choose a specific RT model solely based on chucks (unless you have an expensive one you want to utilize). Because there are many other RT specific purchase considerations.
Centering. If your woodworking application is not fretting about a few thou here then lucky you. For precision metalworking its often necessary to ensure chuck clamping is absolutely concentric with RT rotation axis. I've had pretty good luck with most jobs dropping an morse taper arbor into the RT, lightly closing the chuck jaws down on the extending stub, then clamping the chuck to RT into that position. But you can only do this with either a FM chuck or an inter-plate ie. an assembly that facilitates the chuck being able to float a bit & then clamped down. If OTOH the chuck is 'fixed' to the RT by some rear mount centering plate & no way to adjust it, that can introduce runout & you are stuck with this. So another option is get an independent jaw 4-jaw chuck which you can dial in to the work, same deal as a lathe setup. This also allows you to hold non-round work & offers 1 more jaw over a 3. But that takes more time to set up each job.
Other RT purchasing considerations. If you are holding things that require tailstock support in vertical mode, consider looking for brands that sell matched tailstocks. If you find yourself wanting to index to fixed divisions repetitively (as opposed to rotating or arriving at odd angular increments) then consider getting dividing plate set that might be offered with RT. Also, you may want to look at a dividing head which is a different animal but may offer some advantages over a RT.
Here is a sketch of a Gator 5" dia 4-jaw independent chuck perched on a 6" dia RT with 4 T-slots using a self-made inter-plate just to give you a visual. I just received the chuck so will be starting on the plate soon. The 4-jaw chuck has 4 rear mount (only) threaded holes for mounting. I checked the 5" gator 3 jaw & it has 3 holes but same circle pattern & same recess in the back (red arrow). So that's why the odd looking bolt pattern in the plate - so I can both 3 & 4-jaw chucks on same plate.
Re chuck recess - pretty much every plain back has this & its intended to engage a matching protruding boss typically on the lathe adapter plate. But the diameter & depth vary my manufacturer. And don't get this confused by Set-Tru & similar 'adjustable' chucks, those are different again. Anyway, thinking about this some more, I think I want a similar protrusion on my adapter plate as opposed to just flat. If the chuck is only clamped with the bolts, it probably wont move around in horizontal mode. But in vertical mode the chuck's weight wants to slide it down. Now add any quill machining force on top & that might nudge things if the bolt hole clearances will allow it. But then again - its only 4 bolts that are holding the plate to the RT.
I'll let you know how/if it turns out
Re chuck recess - pretty much every plain back has this & its intended to engage a matching protruding boss typically on the lathe adapter plate. But the diameter & depth vary my manufacturer. And don't get this confused by Set-Tru & similar 'adjustable' chucks, those are different again. Anyway, thinking about this some more, I think I want a similar protrusion on my adapter plate as opposed to just flat. If the chuck is only clamped with the bolts, it probably wont move around in horizontal mode. But in vertical mode the chuck's weight wants to slide it down. Now add any quill machining force on top & that might nudge things if the bolt hole clearances will allow it. But then again - its only 4 bolts that are holding the plate to the RT.
I'll let you know how/if it turns out