Quick Change Tool Post Indexing

[J Tiers]

I'd have probably used a spring plunger or ball, and made it so all that had to be done was to loosen, turn, and tighten. As far as I know, that is how most of the indexing posts did it, and it would suit what I do.

I tend not to like pins that need to be removed and put in a different hole. Sometimes you have to, sometimes not. Do you plan to make the pin tapered so that it can be a tight fit?

[JRouche]

I'd have probably used a spring plunger or ball, and made it so all that had to be done was to loosen, turn, and tighten. As far as I know, that is how most of the indexing posts did it, and it would suit what I do.

I tend not to like pins that need to be removed and put in a different hole.

A ball detent sounds like a nice idea. I like it. JR

[npalen]

I'd have probably used a spring plunger or ball, and made it so all that had to be done was to loosen, turn, and tighten. As far as I know, that is how most of the indexing posts did it, and it would suit what I do.

I tend not to like pins that need to be removed and put in a different hole. Sometimes you have to, sometimes not. Do you plan to make the pin tapered so that it can be a tight fit?

I had planned on using a straight pin similar to that on a speed indexer but agree that a tapered pin would be better. I also like the idea of a spring and ball detent as several have mentioned. It would be easy to implement and I probably still have these items with the 4-way post original to the lathe.

It might be feasible to do the ball detent thing also in about three positions under the t-bolt but will need to give that a bit more thought. Capturing each ball and spring (think ball type oiler) would be a plus to eliminate having to fiddle with them when changing toolpost between the three positions.

Again, I appreciate all your feedback even that which may seem a bit harsh at times.

[J Tiers]

Depends on the absolute accuracy and repeatability you want/need. The "spin indexers" have a pin and hole setup for accuracy and repeatability.

The ball or plunger may not be quite as repeatable as a good reamed taper pin locating setup, but is a lot faster and easier to operate. I think I would opt for the spring plunger instead of the ball, since it probably would locate just a bit better.

I figured the spin indexers would use a tapered pin, but apparently they don't? I do not have one. I thought of getting one, but I have more 3C than 5C collets. When I finish the Rivett, I'll have to get more 5C, since it takes them in the spindle, so then a spin indexer would make sense.

[npalen]

Depends on the absolute accuracy and repeatability you want/need. The "spin indexers" have a pin and hole setup for accuracy and repeatability.

The ball or plunger may not be quite as repeatable as a good reamed taper pin locating setup, but is a lot faster and easier to operate. I think I would opt for the spring plunger instead of the ball, since it probably would locate just a bit better.

I figured the spin indexers would use a tapered pin, but apparently they don't? I do not have one. I thought of getting one, but I have more 3C than 5C collets. When I finish the Rivett, I'll have to get more 5C, since it takes them in the spindle, so then a spin indexer would make sense.

Would the spring plunger be more difficult to implement in the design? What would it look like?

[J Tiers]

Would the spring plunger be more difficult to implement in the design? What would it look like?

Maybe.... it just means the plunger goes where the ball was. The advantage is that the plunger should locate in it's hole better than the ball, and have more sticking out. The ball has to have it's largest diameter in the hole, and also be held in by some sort of staking, so there is less poking out to locate in the matching hole. I think one could do better with the plunger.

The spring / plunger hole would be deeper than the one for a plain ball. Might not be a big issue if located in the t-nut, with the receiving holes in the toolpost.

There are many possible variations with better locating which are possible if there is space available, and a slight added trouble of moving the toolpost is accepted. For instance a taper-ended pin and hole setup could be used if you accept pushing down a button or lever to move the toolpost. (the ball or rounded plunger would automatically "snap" out of the locating hole, but the tapered plunger would not).

For really repeatable locating, a double tapered end pin setup could be used.... one on each side of the pivot. That would also use a button or lever to release)

[masheenest]

What's with all these plans to reposition a "QUICK CHANGE TOOL POST" ? Why not "Quickly Change" tools to one with the desired shape?

[npalen]

What's with all these plans to reposition a "QUICK CHANGE TOOL POST" ? Why not "Quickly Change" tools to one with the desired shape?

You can go back and read all the posts but an example would be rotating the QCTP a few degrees clockwise to avoid interference of the turning tool with the live center and then easily rotate back to its home position for a cutoff or other tool. Another example would be rotating the post 45 degrees clockwise to do a right hand chamfer with a turning tool or 15 degrees to do a left 45 chamfer with a triangular insert using the 30 degree edge.

I have eight tool holders for the QCTP that are all full of various cutters and reluctant to buy more. Need to make use of what I have and an indexing QCTP seems to be the answer as it would also be quicker that changing tools. Basically, it combines the advantages of QCTP and 4-way indexing toolpost.

[Mcgyver]

I never had the need.

-D

The need for what, an indexable tool post? Like Multifix or Drehblitz? It comes from making multiple parts that require tool/position changes. I'd have thought that obvious.

[BCRider]

The spindexers do have a tapered pin. At least mine does.

Going back to the post's stud doing double duty. Don't be surprised when the differences in friction between the T nut and the top nut also result in the T nut end loosening and you loose your positioning. Such is the situation when the stud is not captured.

When I use my mill table clamping kit and loosen the upper nuts it's a 50-50 shot if the stud comes out with the nut or the nut comes off the stud. Another reason why it's not a good idea to use the center stud for the dual jobs. At least not without some way to lock it to the T nut.

[npalen]

The spindexers do have a tapered pin. At least mine does.

Going back to the post's stud doing double duty. Don't be surprised when the differences in friction between the T nut and the top nut also result in the T nut end loosening and you loose your positioning. Such is the situation when the stud is not captured.

When I use my mill table clamping kit and loosen the upper nuts it's a 50-50 shot if the stud comes out with the nut or the nut comes off the stud. Another reason why it's not a good idea to use the center stud for the dual jobs. At least not without some way to lock it to the T nut.

Would you let me put a spring and ball in the bottom end of the stud and then lock the stud in the t-nut? This along with about three detent positions in the bottom of the t-slot?

[no704]

I just use a square.

[Randy]

FWIW here's my indexing QCTP laid out. Maybe you'll get a useful idea or two. The body has a circle of 24 holes drilled and reamed to barely clear 3/16" dowels. The base ring has two dowels for holding, and one 1/4" ball with a spring for pre-positioning and tactile feedback. The center screw is made from a long 5/8" setscrew. It secures the base ring to the compound with a hex wrench, while the top handle holds the body. By backing off the top handle one turn, the spring raises the body just enough to clear the dowels, but the equator of the ball remains in its pocket, allowing the body to turn with a nice click-click-click. The ball isn't captive in the base ring, so I mustn't raise the body too much or the ball will come loose. I have a spring/ball/detent in the top handle to hold it at one turn. That's not necessary, nut nice. You can see that I made the base ring with four dowel holes and four spring/ball pockets, but that turned out to be unnecessary. One spring/ball is enough, and two dowels are enough for positioning. The base ring has an o-ring to keep out debris. I know that, in principle, it can't be absolutely repeatable since there has to be a slight clearance for the dowels, but it's pretty darn close. Tightening the top handle takes out whatever slack there is the same direction every time, so it repeats to a few tenths.

[J Tiers]

I worked up a design very similar to that a couple years ago, for adding to the 4 way post I have, but have not gotten excited enough about it to do it yet. I loosen the post a lot to do different things, and some reference points would be good for faster setting when doing repetitive operations.

I just use a square.

I use a spare 1 2 3 block. But, it would be more convenient to go to a defined position, taking a good deal less time and hassle setting it up. Fewer moving parts......

[npalen]

FWIW here's my indexing QCTP laid out. Maybe you'll get a useful idea or two. The body has a circle of 24 holes drilled and reamed to barely clear 3/16" dowels. The base ring has two dowels for holding, and one 1/4" ball with a spring for pre-positioning and tactile feedback. The center screw is made from a long 5/8" setscrew. It secures the base ring to the compound with a hex wrench, while the top handle holds the body. By backing off the top handle one turn, the spring raises the body just enough to clear the dowels, but the equator of the ball remains in its pocket, allowing the body to turn with a nice click-click-click. The ball isn't captive in the base ring, so I mustn't raise the body too much or the ball will come loose. I have a spring/ball/detent in the top handle to hold it at one turn. That's not necessary, nut nice. You can see that I made the base ring with four dowel holes and four spring/ball pockets, but that turned out to be unnecessary. One spring/ball is enough, and two dowels are enough for positioning. The base ring has an o-ring to keep out debris. I know that, in principle, it can't be absolutely repeatable since there has to be a slight clearance for the dowels, but it's pretty darn close. Tightening the top handle takes out whatever slack there is the same direction every time, so it repeats to a few tenths.

Wow! That is awesome and so pertinent to this thread! Nice work!
Edit: Thanks for posting!