Gallery, Projects and General > Project Logs

Modifying a Southbend Headstock for Indexing

<< < (9/16) > >>

SPiN Racing:
 :scratch:



Im watching... and learning (gonna learn to cut threads later today I think)........ BUt I still dont know what it will be.  :scratch:

Darren:
Ralph,

I too put off having a go at threading. When you read how it's done it all sounds very complicated. There seems to be quite a lot involved in setting up and actually doing it.

For my first go I skipped some of the procedures.

I cut a 1mm pitch thread on a 22mm dia and it worked fine, easy. Then I tried the same on a 6mm dia. The nut threaded on perfectly.

First I set the lathe to cut the pitch with the change gears. Positioned the tool for the first light cut, locked the saddle nut and switched on. When close to the chuck I simply reversed the lathe motor keeping the saddle nut locked. Didn't retract the tool or use the threading dial at all.
Then advanced the tool slightly and cut the next depth. Repeat till the nut fits.

Easy..... :thumbup:

I'm not saying it's the correct way to do it, but good for starting out as there is a lot less to think about.

bogstandard:
Darren, there are a few methods for thread cutting that can be used.

One is the straight in approach, which was most probably the one you used, and there is the offset topslide method, which is the one I prefer because it puts less strain on the cutter and machine. But each to his own.

But always, if you are going for low TPI for imperial, or large pitches in metric, it is always better to make the cut manually using a handle on the end of the leadscrew to turn the machine. I have yet to mod my machine, but it will be done in the not too distant future. The reason being, going to these size of threads puts a lot of pressure on the change gears and is liable to smash them. DAMHIK.

John

Darren:
Hi John,
I did offset the slide, but only cos I'd read about it somewhere and this being a small machine.

Good point on the hand wheel, I must make one for myself as well.... :thumbup:

Bernd:
Ok, I got more done on the index head today.

First pick is of getting the sacrificial faceplate nice and even.



Next I need to get the part somewhat centered on the hole I'm going to bore out. I took a piece of aluminum and put a 60 degree taper on the end. The other end is held in the tailstock by the drill chuck.. The clamps are just tight enough to hold the part in place.



I then use the tailstock to push the part up against the faceplate. This will get the alignment close. After I get it close I use and indicator to bring the hole in to about .001 to .002" run out. Tighten down the clamps and ……………



…….. start boring out the hole to the required dimension, which is 1.625" (41.3mm). It looks like the part is spinning at a high rpm's but is actually on the lowest pulley combo before going to the back gear. I really don't have any idea of speed on this machine. It came with out a chart for speed.



Here you can see the cotter blank being scalloped to the dia of the bore.



And the bore is to size ready for a test fit on the spindle of the index head.



Yup, great fit on the spindle. Just a couple of tenths looseness. Next will be to bore the second hole so it will fit on the shaft behind the spindle. Then the cotter clamp will be finished up.



That's it for now. Maybe tomorrow I'll get the other hole bored to size and get the clamp permanently mounted on the index head.

Bernd

Navigation

[0] Message Index

[#] Next page

[*] Previous page