Quick Change Tool Post Indexing

[npalen]

I'm looking at a way to allow indexing (clocking?) of my QCTP at various angles so that a turning tool, for example, can be easily rotated to a chamfering angle such as 30 or 45 degrees. This would involve loosening the central bolt or nut, removing a small pin, rotating the tool post, reinserting the pin and tightening the bolt. Returning the post to it's starting position would, of course, be a reversal of the process.

The paper in the picture shows what would probably be, say, 3/8" thickness aluminum with embedded magnets that would grab the toolpost. The hole in red would have a small hardened drill bushing that would be used to drill a 1/8" hole, for example, into the top of the cross-slide into which a pin would be dropped thru the hole of a selected angle which are shown on 15 degree increments.

Would be easy enough to add pin positions for special angles such as 29.5 degrees for single point threading.

Would be good to hear feedback from you guys..

[Doozer]

I never had the need.
I can eyeball formed chamfers and bevels like 30° and 45°
and if you really need a cut chamfer or bevel, just use the
compound. Not sure threading enters into it.
It sounds like you have a fix for a problem that does not
exist.

-D

[thin-woodsman]

if you really need a cut chamfer or bevel, just use the
compound.

Or, if changing the compound is too inconvenient, use an angle gauge with the protractor aligned along the edge of the compound, and the arm up against the QCTP.

You're really keen to involve a magnet in the process, use a magnet on top of the angle gauge to hold it in place

[npalen]

Wow! Tough crowd around these parts! You never have the need to briefly change the angle of your cutting tool? Why do people invest hundreds of dollars in multifix tool posts? Why do people use spin indexers, where a pin is used to quickly establish the angle, when a protractor could easily be used. Why do people use dividing heads? etc etc etc

[J Tiers]

The method existed for 4-way toolposts.

Sure you could get a wrench, loosen the compound, brush away the swarf, eyeball the setting against the little index line, and then use the wrench to lock it down again before putting the wrench back, but it is simpler and faster to just loosen with the top lever, turn to a detent, and slam the lever back to lock.

Or, just get a 40 position Multifix toolpost to begin with.

I use a specially made 4 way, but it has no detent. I eyeball the angle, and have no issues. If you need a specific angle, OK.

[JRouche]

I'm looking at a way to allow indexing (clocking?) of my QCTP at various angles so that a turning tool, for example, can be easily rotated to a chamfering angle such as 30 or 45 degrees. This would involve loosening the central bolt or nut, removing a small pin, rotating the tool post, reinserting the pin and tightening the bolt. Returning the post to it's starting position would, of course, be a reversal of the process.

The paper in the picture shows what would probably be, say, 3/8" thickness aluminum with embedded magnets that would grab the toolpost. The hole in red would have a small hardened drill bushing that would be used to drill a 1/8" hole, for example, into the top of the cross-slide into which a pin would be dropped thru the hole of a selected angle which are shown on 15 degree increments.

Would be easy enough to add pin positions for special angles such as 29.5 degrees for single point threading.

Would be good to hear feedback from you guys..

I like it.. I used a sharpie to mark a couple angles I use often. Eyeballing it for me creates different angles, that I dont like. If the chamfers look different it just looks crappy. Your tool would be easy, fast and a fun project. Not all the folks here are rude and unsocialized, so just grin and bear it JR

[BCRider]

To some extent I agree with the others that you're making up a need. But I also see some advantage to occasionally being able to set the post at a few angles such as in repetitive production of a few parts. There's been a couple of times over the years where I wished I could set and restore tool post positions. Mostly it was when I was making repetitive parts that needed the tools to be moved to some other angle.

You're doing this up so it's all external from what I can see. More of a positioner than a way to clock it true each time. The problem that I see is that when you loosen the tool post to set it you have play of the T nut in the compounds T slot and you have play between the hold down bolt and the body of the tool post. Your only fixed position would be your pin in the arrangement of holes. Now you could twist the tool post so it pivots around that pin until all those clearances are taken up. But if the force you use should lever the tool post away from contact with the gauge? I'm not liking those odds.

Plus if you want this to work you're locking the tool post into one position within the compound's T slot. I've had a lot of times where being able to slide the tool post to one side or the other of the compound's T slot was needed for clearance. You could still move your post in this way but you'd loose out on the indexing.

Now my own lathe has a rather wide T slot. The upper opening is a whisker more than 1.25 inch. Metric something or other. So I've got enough room to drill for at least 12 x 30° positions. Or if I put a small spring loaded pin into the T nut I could have even more room to drill a ring of shallow indexing holes directly into the base of the tool post. For this to work I'd also need to drill and tap the T nut for some set screws that hold the T nut in position. Otherwise each time I loosen the post to rotate it the T nut would shift.

Being spring loaded the pin could be used or ignored. And since the spring pin would be in the T nut I think I'd drill and set it up with a wire "switch" that traps the pin down so it's not used for normal work but could be enabled for times I want to index the post.

And best of all I would not need to do anything to the compound. Just drill some locking setscrew holes in the T nut, a hole for a spring and pin in the T nut, and a ring of shallow indexing holes into the lower face of the tool post.

Working with the bigger diameter of the lower face of the tool post I could also have good room for a 24 x 15° ring of indexing holes too. And that would cover setting the tool post back to "square" for a lot more possible angle cutting options on the compound's angle.

[npalen]

The method existed for 4-way toolposts.

Sure you could get a wrench, loosen the compound, brush away the swarf, eyeball the setting against the little index line, and then use the wrench to lock it down again before putting the wrench back, but it is simpler and faster to just loosen with the top lever, turn to a detent, and slam the lever back to lock.

Or, just get a 40 position Multifix toolpost to begin with.

I use a specially made 4 way, but it has no detent. I eyeball the angle, and have no issues. If you need a specific angle, OK.

" but it is simpler and faster to just loosen with the top lever, turn to a detent, and slam the lever back to lock."
I miss that having removed my 4 way toolpost but gave it up in favor of the QCTP for quick changing of cutting tools. Seems that I never had the tool needed in one of the four corners.

I see people removing their compound slides and replacing with a rigid mount between the cross slide and toolpost. The pin indexing would give them a method of easily changing tool angle also.

I like the multifix tool posts but they are very expensive and the increments of 9 degrees (40 positions) doesn't make sense to me when 15 degrees give 30, 45 and 60 capability. I tend to keep my compound at 30 degrees but just thought an easily selectable 29.5 angle would be nice for single point thread. I just hate loosening the four bolts and getting down under with a light to see the graduations.

https://www.abmtools.com/product/quick-change-tool-post-set-multifix-40-position-5-pc-set/

[Doozer]

I have no earthly idea why people buy those Multi-fix toolposts.
Best I can figure it is some OCD brain reason that they think they need some
perfectly indexed postiton. I have never in my home shop or when working
as a machinist in a commercial shop, needed to have a perfect known angle
on my toolpost. If you cut threads, you use a fishtail gauge. But that's it.
It is a manual lathe. Aloris type is the best solution I have seen so far.

And for the compound when threading, if you honestly think you need 29.5°
and 30° is not close enough, you really must have your eyes closed.
I don't even thread with the compound. My threads look great.


-Doozer

[BCRider]

Doozer, you're starting to sound like an old curmudgeon.... just like the rest of us

[npalen]

To some extent I agree with the others that you're making up a need. But I also see some advantage to occasionally being able to set the post at a few angles such as in repetitive production of a few parts. There's been a couple of times over the years where I wished I could set and restore tool post positions. Mostly it was when I was making repetitive parts that needed the tools to be moved to some other angle.

You're doing this up so it's all external from what I can see. More of a positioner than a way to clock it true each time. The problem that I see is that when you loosen the tool post to set it you have play of the T nut in the compounds T slot and you have play between the hold down bolt and the body of the tool post. Your only fixed position would be your pin in the arrangement of holes. Now you could twist the tool post so it pivots around that pin until all those clearances are taken up. But if the force you use should lever the tool post away from contact with the gauge? I'm not liking those odds.

Plus if you want this to work you're locking the tool post into one position within the compound's T slot. I've had a lot of times where being able to slide the tool post to one side or the other of the compound's T slot was needed for clearance. You could still move your post in this way but you'd loose out on the indexing.

Now my own lathe has a rather wide T slot. The upper opening is a whisker more than 1.25 inch. Metric something or other. So I've got enough room to drill for at least 12 x 30° positions. Or if I put a small spring loaded pin into the T nut I could have even more room to drill a ring of shallow indexing holes directly into the base of the tool post. For this to work I'd also need to drill and tap the T nut for some set screws that hold the T nut in position. Otherwise each time I loosen the post to rotate it the T nut would shift.

Being spring loaded the pin could be used or ignored. And since the spring pin would be in the T nut I think I'd drill and set it up with a wire "switch" that traps the pin down so it's not used for normal work but could be enabled for times I want to index the post.

And best of all I would not need to do anything to the compound. Just drill some locking setscrew holes in the T nut, a hole for a spring and pin in the T nut, and a ring of shallow indexing holes into the lower face of the tool post.

Working with the bigger diameter of the lower face of the tool post I could also have good room for a 24 x 15° ring of indexing holes too. And that would cover setting the tool post back to "square" for a lot more possible angle cutting options on the compound's angle.

I like the way you're thinking!

I was waiting for someone to mention the loss of position when loosening the tool post and the need to occasionally move the tool post to a different position along the length of the t-slot. My lathe uses a t-nut with a stud that can be screwed down tight to the bottom of the t-slot locking it in place. That could be complemented by drilling the indexing pin hole at two or three corresponding positions in the top of the compound slide. The bottom of the t-slot could also be drilled with matching holes for the t-slot stud to engage.

[J Tiers]

.....................................

The problem that I see is that when you loosen the tool post to set it you have play of the T nut in the compounds T slot and you have play between the hold down bolt and the body of the tool post. Your only fixed position would be your pin in the arrangement of holes. Now you could twist the tool post so it pivots around that pin until all those clearances are taken up. But if the force you use should lever the tool post away from contact with the gauge? I'm not liking those odds.
.................................................. ................................

The indexing posts lock the t-nut position so it's not going to slide. And they usually have minimal slop and/or a means to locate the post relative to the holding post, so that the indexing works repeatably.

Adding that stuff seems likely to add significant height. There is no room to add it inside the toolpost, which is also hardened. So it has to go below.

What I see as nice about really positive indexing is the ability to set at a dead-on 90 deg whenever a parting-off operation is needed (and nice for threading as well). The other angles are nice, but not really "required".

The point about the 9 degree indexing is well taken on the Multifix. It DOES do a reliable 45 degree, but no 30 and no 60. I'll agree that 45 is the most commonly needed angle for chamfering, but.....

The other thing is that aside from 90 deg, no other angles are good for much aside from a chamfer, since there is no other angle to move the tool along a slide beside 90 or the typical 29.5 deg threading angle. To get any of those, you need to turn the compound, and most machines are not like a Rivett, where the compound is locked by a convenient lever.

[Doozer]

Doozer, you're starting to sound like an old curmudgeon.... just like the rest of us

Some people try to do it by the book
and some people do what is shown to have results
and realize the book is just to get you started and
anyone who understands the scientific method of
cause and effect reasoning will graduate their mind
and exceed the knowledge contained in the book.
People who follow the book exactly, will never be
smarter than their book. Be it the machinery bible
or the holy bible.

-D

[J Tiers]

Some people try to do it by the book
and some people do what is shown to have results
and realize the book is just to get you started and
anyone who understands the scientific method of
cause and effect reasoning will graduate their mind
and exceed the knowledge contained in the book.
People who follow the book exactly, will never be
smarter than their book. Be it the machinery bible
or the holy bible.

-D

Then there is "do it like the print says", which is required in order to get paid. "Innovation" and "creativity" are not welcomed when the print says "the feature is to be like this".

[Randy]

I think your idea is promising. Soon after I got my lathe I tired of the lantern toolpost, so I made a four-way toolpost. I had seen a catalog photo of a Royal four-way which indexed, so I emulated that in my design. It indexed in 15° increments and was quite repeatable. It served me well for many many years. Eventually I upgraded to a shop-built QCTP, but I wanted to keep the indexing feature, so I kept what I could of the four-way and made a new body to fit it, with a dovetail clamp. I can use it exactly as you propose, swing it around for a quick chamfer, then return to normal position. However, I find it just as convenient, if not more so, to change to a chamfer tool holder and back to a turning tool, because I don't have to crank the cross slide a couple of inches and back, which turning the toolpost requires. One place it really does help is when using the tailstock center. I find that the toolpost body will often clash with the tailstock or the live center itself when using the center with a small diameter workpiece, so turning the toolpost cw one ot two steps solves that problem. Also, I needed to build my QCTP with only one dovetail rather than the usual two, since I can swing it to both turning and boring positions.

But is indexing really that helpful? Well, with a four-way I think indexing is essential, in order to be repeatable. So I got fixated on it. But for a QCTP with two dovetails, not so much. Don't get me wrong, I like the indexing feature, it's a nice luxury, but I rarely use any but the two normal positions. The tailstock clearance issue is real, but sticking the tool out a bit farther works, too.

Indexing might be a bit of a gimmick, but I kinda like gimmicks. And I use it, though less than I anticipated.