Ensure my toolslide's parallel to spindle axis

[fluxcored]

Hi All,

I've been fumbling along for quite some time now and about 3 weeks ago I discovered when I use my toolslide to make fine cuts I'm turning taper.

After measuring, dismantling and lots of investigation I discovered to my chagrin that the degree scale on the cross slide cannot be trusted.

Now since I can't use the cross slide's scale as a reference anymore, I'm a bit ... stuck.

It's taking me ages to get the darn thing parallel and I'm really just guessing when I set the cross slide to cut tapers.

Can somebody please please give me a hint on how to ensure the cross slide is set exactly parallel. And also how to set at a certain degree. And what tools to use - I have'nt yet bought a machinist protractor. Any tips welcome.

One last thing - I use the toolslide for final cuts because I get a better finish. I assume that is the way that you finish off a turned piece?

Regards

[John Rudd]

Are you sure its the topslide that is out of alignment and not the tailstock?

When I make finishing cuts I usually use the carriage handwheel, moving slowly, with a high spindle speed and a good sharp tool...the latter having the greatest effect on the finish...

Others may have a better way.....

[Bernd]

Flux,

First we need to get some terminology straight. I'm assuming your calling the "compound slide" the "topslide". This holds the tool post. Under your compound slide is the "cross slide".

I believe you are also saying that you are using the compound slide to finish turning by having it paralell to the lathe axis.

To get your compound slide perfectly paralell you need to mount a test bar or some kind of smooth round bar in the chuck. Then use an indicator on the center line of the bar to set the slide to "0".

A protractor for setting the angles is a start. The taper would still need to be "tweaked" to get it to fit the part it's supposed to fit. It's a guessing game at best.

Regards,
Bernd

[fluxcored]

John, my tailstock was out of alignment which I then set correctly. Making cuts now with the cross slide only, does not induce taper. I've resorted to making finishing cuts exactly like you describing without any noticeable taper but poor finish.

I'll work on my speeds and grinding of cutting tools shortly. I just wrongly assumed that for better finish you must use the top slide. And it did.

Bernd, yes you're correct on all counts. Sorry for causing confusion. I'm using the Boxford manual and it defines it's compound as having a compound slide (swivelly bit), top/tool slide (back and forth thingy) and a toolpost.  All that is on the cross slide.

But we're on the same page.

For parallelism, I salvaged the carriage shaft of an old dot matrix printer which in my mind should be pretty accurate. So I just remove the toolpost and put the indicator in its place and adjust accordingly?

I'll get a machinist's protractor which should be more accurate than the one I'm using.

[Bernd]

Bernd, yes you're correct on all counts. Sorry for causing confusion. I'm using the Boxford manual and it defines it's compound as having a compound slide (swivelly bit), top/tool slide (back and forth thingy) and a toolpost.  All that is on the cross slide.

But we're on the same page.

For parallelism, I salvaged the carriage shaft of an old dot matrix printer which in my mind should be pretty accurate. So I just remove the toolpost and put the indicator in its place and adjust accordingly?

I'll get a machinist's protractor which should be more accurate than the one I'm using.

No problem. Just wanted to make sure we were talking about the same thing.

The shaft from the printer should work just fine if it's big enough in diameter to get an indicator pointer on the center line. Don't know if you'd need to remove the tool post. As long as you can set up an indicator so you can set the compound slide up you should be all set. If you could post a picture of the set up we could see if you got it correct.

Bernd

[ariz]

there is no need that the test bar was perfectly straight
you may turn the chuck and sign the higher and lower reading of the dial indicator, then take the average (middle)
repeat this operation near the headstock and near the tailstock until you get the same readings (same average reading)

hope to had explained, sorry for my english 

[Davo J]

Another way is to mount a magnetic base to the ways or the chuck and have the dial indicator touching the side of the compound, move the (carriage) back and forth and adjust until the dial indicator needle doesn’t move.
Dave