Setting lathe QCTP tools on centerline

[BCRider]

J.....But I wonder, if it's my grandmother's brother, does that make it my great uncle?

Just stop...... No more "Dad" jokes!

Mickey, I have to admit that I "assumed" that the top was flat and parallel to the spindle. And we know how that goes But you've activated my OCD and I will be checking in a few minutes.... But the boring bars I've set by using the short tool moved around on the top flat have all cut well.

I've bought a bunch of holders for my own QCTP. But I know I change them on occasion so having a checker that doesn't require me to remove the work from the chuck is preferred. Plus for the bigger boring bars the QCTP comes off and I go with my home shop made bars and post. And those bars are frequently moved to alter their extension to suit the job. So they need to be checked when that is done. So the height checker gets used more frequently than having a QCTP would suggest.

Mr Whoopee. I love the spring loaded swing away top plate for testing against the tips being too high. I was wondering about fitting such a top plate to my short gauge. I'll be copying what you did with the spring regardless of it being your idea or not.


EDIT- Mickey, did you clean up the lathe for the photo shoot? I scrolled up past your pictures again and noticed that there isn't a single spec of swarf even in the corners! Or did you buy a new lathe just for the pictures?

[mikey553]

EDIT- Mickey, did you clean up the lathe for the photo shoot? I scrolled up past your pictures again and noticed that there isn't a single spec of swarf even in the corners! Or did you buy a new lathe just for the pictures?

No, my 12 x 36 lathe is 17 years old, I bought it new from Grizzly. I try to keep the top and the ways free of chips using a small paint brush you see on one of the pictures. So chips fall at the bottom pan, where they collect for a long time.

[BCRider]

I keep a cheap paint brush at each of my machines for brushing chips away too. But it never cleans out the corners like you managed. I salute your superior clean freakiness ! ! !

[mikey553]

You are probably looking at the white pan right under the chuck. This aluminum pan covers the bolting for the removable gap. It is clean now because I removed it 2 days ago to look at the bolting. Usually it is full with chips and I don't clean them up for months.

Do you have such removable gap in your lathe? I think in theory it allows to place up to 19" diameter short parts on this small lathe. But in reality I am afraid to remove it. I think it will never go back in the same position as before. I would rather not have this gap at all.

[MrWhoopee]

Do you have such removable gap in your lathe? I think in theory it allows to place up to 19" diameter short parts on this small lathe. But in reality I am afraid to remove it. I think it will never go back in the same position as before. I would rather not have this gap at all.

The gap is usually pinned in some manner to assure accurate reinstallation. You can (and probably should) run an indicator along the ways after reinstalling to be sure. The removable gap is a definite plus.

[BCRider]

Never had mine out either. Never needed to. And like you I've seen references that say it won't match up again without a good fight.

Great minds think alike too it seems. Check the pictures in my first post in this thread and you'll see a sheet aluminium cover over the first opening just under the chuck. And likely our machines both share the same bed casting. I don't recall exactly why I put the cover in but I'm guessing that with the gap at that point it likely was a PITA to clean out.

I brushed off my tool post for my pictures too. But you can see how much fine swarf is still stuck to the oil on the surface.

[Jim Stewart]

You are probably looking at the white pan right under the chuck. This aluminum pan covers the bolting for the removable gap. It is clean now because I removed it 2 days ago to look at the bolting. Usually it is full with chips and I don't clean them up for months.

Do you have such removable gap in your lathe? I think in theory it allows to place up to 19" diameter short parts on this small lathe. But in reality I am afraid to remove it. I think it will never go back in the same position as before. I would rather not have this gap at all.

When I got my HF 12X36 20-some years ago I checked out *everything* it had including the gap bed.

Took it out, checked the swing, put it back together. No issues.

There is a small gap between the bed and the gap piece, but no difference between the level of them. I didn't run a DI over the bed but I've never noticed a difference in actual use.

-js

[thin-woodsman]

What do you think about it? It is a big help for me and I would like to share it with you.

I'd worry that the drill rod wasn't running accurately in the chuck, but I guess you can always clock that with the indicator.

The last time I did a bunch of QCTP holders, I used a dead-center and a surface gauge. The surface gauge was set off the point of the dead center, and has pins to register on the ways. I would register the tool bit against the point of the dead center, just under (and touching) the curved scriber tip of the surface gauge. Later, I fined-tuned the surface gauge setting when doing a facing cut to get rid of that last little nib. I didn't feel like putting the center in again, so instead i used the surface gauge to scribe marks on an aljminum cylinder, then milled a slot at that height to serve as a permanent(ish) center-height gauge. MrWhoopee's version is an improvement on this, and I'll probably do something similar in steel. I like having a way to register off the top of the toolbit - put an indicator on that top disk to ensure it isn't lifting, and you're dialed in about as good as you can get.

I like Lew's approach, and have something similar, but I keep catching myself thinking "you're using your caveman eyes to look at a bubble of air?!?" and decided to use a more tactile method - which cam be amplified with an indicator to make it feel like you're being more precise, even if you're not

[mikey553]

When I got my HF 12X36 20-some years ago I checked out *everything* it had including the gap bed.

Took it out, checked the swing, put it back together. No issues.

There is a small gap between the bed and the gap piece, but no difference between the level of them. I didn't run a DI over the bed but I've never noticed a difference in actual use.

-js

Was the bed machined under the gap? I am asking because I have seen horrible things Chinese do for a living. I would not be surprised to see as cast surface there and gap assembled on some Bondo.

Actually I detect a small shift of the gap in the horizontal plane, probably a couple of thou. Not sure if it was there from the beginning, but I do not like it at all. I can practically guarantee they assembled the gap piece (on Bondo or not) and then ground the ways. Depending what the bed looks like under the gap I may never be able to put it back in the same position.

[Jim Stewart]

Was the bed machined under the gap? I am asking because I have seen horrible things Chinese do for a living. I would not be surprised to see as cast surface there and gap assembled on some Bondo.

Actually I detect a small shift of the gap in the horizontal plane, probably a couple of thou. Not sure if it was there from the beginning, but I do not like it at all. I can practically guarantee they assembled the gap piece (on Bondo or not) and then ground the ways. Depending what the bed looks like under the gap I may never be able to put it back in the same position.

Yep, the top of the gap and bottom of the gap piece were both ground.

-js

[Richard P Wilson]

None of these fancy dan gadgets works on my lathe which has a cylindrical bed, so I stick to the steel rule method. Its quick and easy, and the rule is always to hand by the machine.

[mikey553]

Never had mine out either. Never needed to. And like you I've seen references that say it won't match up again without a good fight.

Great minds think alike too it seems. Check the pictures in my first post in this thread and you'll see a sheet aluminium cover over the first opening just under the chuck. And likely our machines both share the same bed casting. I don't recall exactly why I put the cover in but I'm guessing that with the gap at that point it likely was a PITA to clean out.

I brushed off my tool post for my pictures too. But you can see how much fine swarf is still stuck to the oil on the surface.

I like your plastic covers for the ways and need to do something similar. That is after I replace the original rubber way seals with felt.

You can cover your lead screw as well. I have used a shower rod plastic cover as was suggested by somebody on this board. The cover is split and I can easily slide it on and off the lead screw from the tailstock side. It covers the whole length of the screw when it is not used for threading.

[QSIMDO]

I keep a sacrificial piece of aluminum bar stock to chuck up for a light face cut with whatever tool I'm setting up.
Adjust for no tit and it's good, no?

[no704]

A student shop that I used to mentor in, each lathe had a dumb bell shaped hunk of steel that was set on the ways and the tool was brought up to the bottom of the top part.

[MrWhoopee]

. I can practically guarantee they assembled the gap piece ....... and then ground the ways.

This how it is always done, regardless of who makes the lathe. It's the only way to ensure perfect alignment.