Thread: Making sense of the threading chart

Looking at the pictures on the H&F site, the positions on the quick change lever are marked 1 to 9, so that will be your 'level'. I suspect it may be Chinese for lever, actually...

Is your lead screw inch or metric? Here in the USA my lathes all have inch leadscrews, so it's pretty easy for me, whereas to cut metric we can't disengage the half nuts. The quick way to check the setup, for me anyway, is to engage the half nuts with the spindle in neutral, pull the chuck around one revolution by hand and check the DRO. Divide and inch ("1") by the number of threads, and the product, in this case .0555", should show on the DRO after one revolution.
I've done it that way, and taught many new hires that, for many years. The other day I was threading a rod 3/8-16 and thought "That's a waste of time, I'll just thread it". Sure as heck I couldn't get the test nut to go more than a turn or two after several extra passes. The light bulb came on in my head, I checked it, and I'd set it at 17 threads per inch.
With my old eyes I learned that I have to check myself.

I agree with J&H -
700 (Medium).jpg 701 (Medium).jpg

I think "Level" should be something like lever position. Remember to flip the handle on the saddle from feed to threading too.

Michael

Originally Posted by oohsam

Hi guys,
I've been getting more and more familiar with my lathe. I've been shown by a friend how to cut threads, so I have all the practical parts down pat, however, I'm having trouble understanding how to set this thing up to cut the threads I want.

I'm making a handle with a 9/16-18 thread that will replace the nut on my Qucik Change Tool post.
It has 18 threads per inch.

What I think I need to do :
First I check the imperial table and find "18", Which I do, Under "LEVEL 2" (i have no idea what level means)
This tells me I need to change the gears on cog A and cog B in the picture to the 30 tooth gear. No problem. I can do that.

The Thread Dial tells me I can select any number on my thread dial between 1 and 8 which is any number. No problem I can do that.

In my head, thats all I need to do, setup my tools, stock, and start threading, but something else is worrying me.


Firstly, I don't know what 'Level' means, because when I look at Metric table, there are a few different 'levels', unlike the Imperial thread chart. There are 9 gears on my Norton style gearbox, So I'm not sure if level means "that number on the gearbox"....Also, There's a feed rate table, which only has 9 and 1 as the level, and it also shows different numbers to change the gears..but I thought this was done already under the Imperial chart.
And then I become confused and have no idea what in the hell i am looking at...

The lathe I practiced threading on was easy...you just selected the levers it told you on the front panel which matched the thread you wanted, and it was ready to go for that thread. This is somewhat confusing.

If anyone can help that would be great.
Cheers




700 (1).jpg700.jpg

Hi there,

So you obviously have an imperial leadscrew (according to the pictures) with a 8tpi leadscrew, hence why you can choose any number on your thread dial pickup. The table indicates you need to be in position (1) on the feed lever. The two gears that sandwich your 127 too gear (in the rear of your headstock) need to be 60 tooth at the top (gear A) and a 30 tooth at the bottom (gear B)

I think that's the way it reads.

Good luck. Hope to see some pics of the result!

Simon

Originally Posted by oohsam

.................I'm making a handle with a 9/16-18 thread that will replace the nut on my Qucik Change Tool post.
It has 18 threads per inch. ...............................

Are you sure the compound bolt is an imperial thread? I would have thought this Chinese lathe uses metric fasteners? Could it be M14x1.5 instead?

Yes,
It is imperial, but the toolpost comes with a "sleeve" to go over the original post which has a metric inner and an imperial outer..
If that makes sense..
Like so :

480.3712.jpg

Originally Posted by oohsam

Yes,
It is imperial, but the toolpost comes with a "sleeve" to go over the original post which has a metric inner and an imperial outer..
If that makes sense..
Like so :

480.3712.jpg

Ok, now I understand. This is like on other chinese 9x20 lathes: the original bolt for the 4-way toolpost is M8. This sleeve fits over it as an adaptor to the larger diameter AXA nmounting hole. Please be very careful when tightening your AXA toolpost onto this much larger sleeve. You can impart an enormous force when tightening the huge nut on this large diameter sleeve. You risk ripping the 8mm bolt out of the compound slide's upper casting. It is actually a "vicious circle" effect. The top surface of the compound casting then bulges upwards - the toolpost rocks on this bulge, prompting the user to tighten the nut even more, the bulge grows bigger..... until the toolpost is completely wobbly no matter how much you tighten the nut. This is not fantasy, it happens often on this lathe model, because the compound casting metal is extremely soft yet very thin.

Originally Posted by cba_melbourne

Ok, now I understand. This is like on other chinese 9x20 lathes: the original bolt for the 4-way toolpost is M8. This sleeve fits over it as an adaptor to the larger diameter AXA nmounting hole. Please be very careful when tightening your AXA toolpost onto this much larger sleeve. You can impart an enormous force when tightening the huge nut on this large diameter sleeve. You risk ripping the 8mm bolt out of the compound slide's upper casting. It is actually a "vicious circle" effect. The top surface of the compound casting then bulges upwards - the toolpost rocks on this bulge, prompting the user to tighten the nut even more, the bulge grows bigger..... until the toolpost is completely wobbly no matter how much you tighten the nut. This is not fantasy, it happens often on this lathe model, because the compound casting metal is extremely soft yet very thin.

Thanks CBA! Duly noted.

What I actually did was create a bushing under it which is about one thread shy of its tightest setting, so its not actually putting the force on the thread, its putting the force on the compound body itself. That pretty much alleviates thats 'upward tension'.

Originally Posted by oohsam

Thanks CBA! Duly noted.

What I actually did was create a bushing under it which is about one thread shy of its tightest setting, so its not actually putting the force on the thread, its putting the force on the compound body itself. That pretty much alleviates thats 'upward tension'.

No. The flanged M8 bolt is pressed from below through the compound casting upper. Look at your compound upper, from the headstock: there are less than 10mm material to keep the M8 bolt from breaking through. Other users have managed to bulge the top of the compound just by tightening the M8 nut to clamp th 4way toolpost. With an AXA toolpost you have a much larger nut (imperial but comparable in size to M15), it can easily pull 5-10 times stronger than the M8 nut. That coupled with the far too soft cast iron used to make the compound castings means that you have to very careful not to overtighten your AXA toolpost, or you will be soon be shopping for a new compound.