Lathe compound questions

[jwmay]

I sometimes see people have made a locking handle for their quick change tool holders, to replace the nut supplied as standard. I’ve recently decided to make one.

But here’s my problem: I watch a ton of YouTube. Stay with me here. That’s a problem, but not the problem.

I seem to constantly be needing a different toolbit, in a different orientation. Which means I’m forever adjusting my toolholder block. Which means I’m constantly losing any reference datum I had. This, to me, is my problem.

I think perhaps I should not be making a special locking handle, because I should instead be leaving the tool holder block alone, in order to keep my zero reference. Isn’t that (generally speaking) best practice?

So other than being smarter, which is very unlikely. Is this fundamentally an “order of operations” or “planning” failure?

An example may be a part that has a larger OD on both ends. I’ve got a left and right inside corner. I’ll invariably switch out the tool, and reorient the tool block doing this job. Somewhere in there, I’ll lose any reference to what’s already been done. My carriage stop will now be in the wrong place, and my dial indicators will have to be reset.

And now we’re back to the YouTube mention. I almost never see anyone reorient their tool holder. So I’m assuming it’s either unnecessary, or bad practice. Is it possible I’ve just taught myself a bad habit?

Here’s an example of the extra handle I began this thread talking about.

What say you folks? Are you reorienting your tool block so often that you need an extra handle? Or does your tool block stay locked in position 99.9 percent of the time?

 

[toprecyler]

I think it comes down to how you have trained yourself to work. And how important you feel it is to keep certain tools at there “position “.

I have a DRO on my work lathe. I have about 16 different holders to keep an assortment of cutting tools on. I do have the DRO tool holder memory assigned to each holder, so when I use my “0” tool to touch off the work, the rest of the holders will have the offsets pretty close.

I say pretty close, because I do not seem to get 100% repeatability when switching out tool holders. It can vary up to .002”.

I would rather have more holders, to keep more tools at the ready, vs having to switch out tool bits. And I’ve been thinking about custom making other tool holders to better support the tool bit at the angle I need to use more often.

This is on my to do list once I get my home shop better set up, just because I can. ( if I find the motivation to make tools for my work when I am off in my home shop, and not stay inside the house watching utube videos or working on my own projects. I tend to loose motivation to work on “work” projects once I am off work, like I should. )

The only problem with having more holders, is keeping them organized so you can store them and see them to pick them out.

There are a couple tools that really need to be aligned super close every time. The threading tool, and parting/ grooving tools. Most other tools can vary and still cut fine, as long as you are close to centerline in Height.


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[jwmay]

So you do not rotate the tool block much at all then, right?

 

[RJSakowski]

The primary advantage of leaving the tool post fixed, usually square to the spindle, is that you can remove tool holders and replace them without the need to re-reference them.

Personally, I prefer to adjust the tool post for optimum orientation for the particular tool I'm using. I grind my HSS and brazed carbide tools so that I can turn and face with the same tool. I find that the amount of time that it takes to re-reference a tool is minimal. When turning, I usually make a trial pass and then measure with a micrometer to reestablish my reference.

I have an dedicated open end wrench for tightening the tool post. If you prefer to leave the wrench on the tool post, you can make a dedicated wrench by cutting a box wrench in half. It can then live on your tool post but can be readjusted or removed easily if necessary. Keith Fenner did just that. Another solution is to use a socket and weld a handle to it.

If you elect to make a special nut with a handle, the nut can be clocked so the handle is in a desired orientation by inserting washers under it.

 

[Just for fun]

My tool post is square with the spindle 99% of the time. I like the idea of having a custom nut and handle and it is in my plans to make one, it's just not high on the priority list.

 

[C-Bag]

FWIW my 9x20 came with that mod on the tool block with a red handle and if it didn’t have it I would have made it long ago. I’m not trained so I can see what you’re saying but like mentioned above my tools are ground to do certain things depending on orientation so I change it all the time. i often need to swing the new tool to recheck it’s centered against a gauge also. I also modded the tailstock lock to get rid of the pesky nut. Some don’t seem to mind grabbing a wrench but I hate it. I don’t misplace handles attached to the lathe

 

[pontiac428]

One possibility is to drill and tap a single hole in your compound (if you dare) and install a pin plunger like the one below, and drill a mating hole in the bottom of your toolpost. You could index to it when needed, and still freely rotate your toolpost too. Your index point relies on two axes for your tool length offset, the rotation axis and the t-slot slide axis. The plunger fixes both, but can be "defeated" and restored as needed without altering the function of your lathe.

KIPP - Spring plungers with hexagon socket and flattened thrust pin, steel

Material: body steel grade 5.8. Thrust pin steel. Spring steel wire grade D. - Surface Finish: Black oxidized. Thrust pin hardened. -...

www.kippusa.com

 

[ttabbal]

I move mine around, depending on the need. I did make a quick handle for the block, so it's really easy to move it around or swap it on/off the compound. I don't need tapers much, so I leave the compound off most of the time and just replace it with a plinth. On my PM1127, it actually came with a spring detent that holds the block straight with a hole in the compound. I didn't like it. The parts for it are in the toolbox with the gears and such now.

I tend to rough in with whatever tool makes sense, then switch to a finishing tool, touch off, light pass and measure to adjust the DRO. It doesn't take that much longer than swapping the datum on the DRO.

If this were a production shop, and I was making a bunch of the same part, leaving the tool angle alone and using offsets would probably make a bigger difference to me. I probably spend more time planning the cut, order of operations, etc. than it would save to avoid measuring after a tool change since I tend to make one of a thing.

 

[MrWhoopee]

I use inserted tooling almost exclusively and rarely change the positon of the toolpost. Some situations will require it, but the right assortment of tooling will minimize the need. I haven't cared enough to learn how to use the tool library (or any of the other fancy features) in the DRO.

 

[Chipper5783]

I don’t hesitate to swing the tool post - but I don’t have a DRO. As others have said, for most tool holders, the angle does not need to be spot on. I have not found that reestablishing the reference is a big deal, it is just called “machining”. My first QCTP is an Aloris style (PhaseII), it works fine, I have about 15 assorted hold.

The next two QCTP systems I bought have been the 40 position type - having now used both, I prefer the 40P. It is rare that one needs to swing the tool post.