Setting lathe QCTP tools on centerline

[BCRider]

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.

The blue cover is some coated nylon with the coated side up. I bought a closeout on some many years ago and can use this as a consumable. Below it is a support tray made from aluminium roof flashing. It's as long as it is because it's attached to the cross slide since I was finding that fine swarf was getting into the dovetail on that side and turning the oil on that side black with metal very quickly. Now both the front and back sides of the cross slide dovetail stay equally clean over a long time. It did mean making up a long clamping bar and drilling and tapping some holes in the cross slide casting. But it's sure aided with keeping chips and fine swarf off the bed and out of the cross slide dovetail.

Have a close look at your plastic wipers. If they are like mine were on both the lathe from 25 years ago and my new mill about 7 years ago the wipers don't even ride against the bed ways. They'll deflect tennis balls but little else. Get some good felt and make up new covers with bent over lips that force the slightly oversize felt into close contact. Your bed will thank you by living a longer unblemished life. I even fitted felt wipers to the front of the tail stock to deflect the swarf when pulling the TS into position. I didn't bother on the rear since the chips don't really land back there.

[BCRider]

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.

What lathe is it you have again? I know that there was a smaller size Boxford with a cylindrical bed. And of course more than a few watchmaker's lathes with them.

[mikey553]

I have just reset the tool height in 23 of my tool holders using the master tool I setup yesterday. It took me exactly 50 minutes to do all of them with +/-.002" accuracy. It would be quicker, but I kept fighting the damned studs getting loose. I really need to put them on Loctite!

You guys keep saying this method is too slow comparing with the ancient steel rule method. I don't think so. It would take me no more than 3 minutes to setup any tool from a scratch using my master and with much better accuracy. By any tool I mean any length and any shape and I don't need to remove a work from the spindle or a tool from the tailstock. Tools can be setup in the same position they will be working. All you need is a magnetic base with an indicator and a place to set it on the machine.

Despite all the benefits only one person said he will try it. I don't get it. It is not like I am going to make any money out of it or apply for a patent. It is up to you, but it hurts my feelings that you don't pay attention on a good thing. I know I would.

It is time to indicate the removable gap on my lathe and decide what to do with it.

[Richard P Wilson]

What lathe is it you have again? I know that there was a smaller size Boxford with a cylindrical bed. And of course more than a few watchmaker's lathes with them.

I've got 2 of them, made by a UK firm called Drummond Brothers between about 1906 and 1940. One is a short bed, c 1920, and the other is a long bed, c 1936. They can remove a surprisong amount of metal given their age and relatively light build.

[BCRider]

DOH! I typed Boxford but I was for sure thinking Drummond.

When I think "model engineering tools" the smaller classic lathes are what comes to mind. And the round bed Drummond is one of those near the top. They really do rank up there with the classic small "model engineering tools" range of lathe. Glad to read that it's a pretty good machine for the size. Frankly looking through some of the fix it threads for the Asian mini lathes I think you're leagues better off with your Drummonds than with the, on paper, similar size mini lathes.

[The Metal Butcher]

I think your setup is nice, but there is a faster way that dates back to lantern Tool post days.
Just hold a ( Aluminum Preferred) 6 inch scale between the work and tool point.
bring the tool in and gently touch the scale to both workpiece and tool ( Clamping it so to speak.
If the scale tilts away from you, you are too high
If it tilts towards you, Too Low
If the scale is vertical, you are on center

Rich
This is one of the reasons old time machinists wore aprons, with the scale pocket in the center of their chests

PS Your method works great if you have multiple tools to set up at the same time using the DI !

This is my method. However, if one is careless, very sharp tools can be chipped. Especially dead sharp threading tools. You can get a tool close with this method and fine tune it by faceing to center. Remember to set all your tools before you bore a hole. That gets me often at work where tools have inexplicably been moved off center for reasons unknown to man.

[BCRider]

I'm thinking that the way with the rule or piece of shim stock would have been more usable before carbide inserts. I can't help thinking that one could fracture a lot of tips with this ruler trick unless pretty high degrees of care were not used.

There's also the issue that on larger diameter work with a lesser change in angle over a degree of vertical change that the ruler trick becomes less precise and more open to an optimistic eyeball's judgement.

Being a fan of HSS I used to just tune the height for a minimal pip on the first facing cuts. But I have to admit that having a good easy to use height gauge that does not rely on swapping tooling in the tail stock or work pieces already in the chuck has proven to be far more convenient, faster and more precise.

Hey Richard, I see that while the bed is round the cross slide still has a flat table on your Drummond lathes. So my own option of spinning the tool post around and using a gauge that sits on the table would still be an option for you. Of course this won't work with a rocker style post if that is still what you use.

[Richard P Wilson]

I'm thinking that the way with the rule or piece of shim stock would have been more usable before carbide inserts. I can't help thinking that one could fracture a lot of tips with this ruler trick unless pretty high degrees of care were not used.

Maybe, but you only need to lightly grip the rule, it shouldn't be enough to damage a tip.



Hey Richard, I see that while the bed is round the cross slide still has a flat table on your Drummond lathes. So my own option of spinning the tool post around and using a gauge that sits on the table would still be an option for you. Of course this won't work with a rocker style post if that is still what you use.

The roundbed Drummond has the facility to rotate the saddle around the bed, about 45 degrees each way, and when this happens, the tool height above the bed varies. Thats the way I set tool height, no shims needed, and I do admit to using the eyeball or facing cut methods as often as not. The height gauge tool just wouldn't work for me.

Rocker style post? Hate them! The Drummonds came with a really rigid block toolpost, and thats what I still use.

[doc0455]

[lynnl]

I'm thinking that the way with the rule or piece of shim stock would have been more usable before carbide inserts. I can't help thinking that one could fracture a lot of tips with this ruler trick unless pretty high degrees of care were not used.

There's also the issue that on larger diameter work with a lesser change in angle over a degree of vertical change that the ruler trick becomes less precise and more open to an optimistic eyeball's judgement.

.....

I have never fractured or chipped a tool tip. But I do now have a 6" scale with numerous pock marks as a result of this use.

You're right of course about less sensitivity with larger work pieces, but as others have described, a facing cut will reveal whether you're on center or not. ...in fact that is the only indicator that really matters.

[Doozer]

I kind of held back to see the ideas presented here.
All of which are very good. For sure.
But I must say that the method I have used for years
was just to face a round piece of steel, and if it leaves
a tit in the middle, the tip of the tool is too low.
Adjust higher and try again, sneak up on it.
I really don't think with turning tools that a little low
is going to hurt, and with boring tools that a little high
is going to hurt. I really think you guys are making
too much of this tool on center thing. Being OCD
about it is just going to make the new bees paranoid
and make using the lathe less fun. Shame on you all.
If it cuts, it works. You are trying to achieve perfection
on something that is not needed. Don't ruin the hobby.

-D

[Butcher]

I kind of held back to see the ideas presented here.
All of which are very good. For sure.
But I must say that the method I have used for years
was just to face a round piece of steel, and if it leaves
a tit in the middle, the tip of the tool is too low.
Adjust higher and try again, sneak up on it.
I really don't think with turning tools that a little low
is going to hurt, and with boring tools that a little high
is going to hurt. I really think you guys are making
too much of this tool on center thing. Being OCD
about it is just going to make the new bees paranoid
and make using the lathe less fun. Shame on you all.
If it cuts, it works. You are trying to achieve perfection
on something that is not needed. Don't ruin the hobby.

-D

thank you!

[MrWhoopee]

You are trying to achieve perfection
on something that is not needed. Don't ruin the hobby.
-D

I find this to be a common affliction on hobby machinist forums. Not having been formally trained or worked in the trade, many have no understanding of what is critical and what is not.

Chasing .0001 when .01 will do.

[mikey553]

I just wanted to help you guys. I guess you cannot teach an old dog new tricks. So stay with your steel rule method.

[macona]

I eyeball it. 99% of the time its close enough. For the other 1% I set it a touch low and face a piece of round and raise it til it no longer makes a nub.