Cutting Metric thread on AL-330

[Sterob]

I've owned the lathe for about 3 years and only now have needed to cut a thread.
It's M18 x 2.5mm and to do so, I've had to swap the 24T and 48T gears around. When I've gone to do this, the 120T gear meshes with the 24T gear ok but the 127T gear touches the lip on the spacer behind the 24T gear. To fix this, I've had to machine the lip off the spacer in order to gear the change gears to all mesh properly.
This seems to suggest that there may be an alignment problem with my lathe or poor quality control ( I know, crappy chinese lathe....lol ).

Has anyone else had to do this sort of modification to their AL-330 H&F , or similar, lathe?

Steve

[scottyd]

I had a hercus 9in in my care once that wouldnt allow gears on the banjo plate to line up with those on the reversing tumbler stub. After a bit of noodle scratching and rooting around, it became clear that the headstock, through years of use, had slowly slid back along the bed, away from the tailstock. A little cleaning, loosening and nudging forward and everything came up good. Maybe a photo of the parts in question on your lathe might help, perhaps something hasnt been made to the correct size or located correctly.

[Sterob]

It seems to work ok but there is very little clearance for the 127T gear, from the spacer.

I have another problem now...I suspect a cap has failed on the motor now.....It was slow starting now it won't spin up at all.
The gear train is free and not binding, but it seemed to happen at around the same time....

WP_20131201_002 (Medium).jpg

[pipeclay]

Did you either try putting the washer behind your smaller gear or just putting a washer there to pack it out a little.

[scottyd]

Could the bottom shaft have been spacer (but in reverse to how you had it), washer then the gear?

[Stustoys]

I had this problem on my lathe(better late than never lol)
First thing you need to check as best you can is the output and input shafts are lined up. My output shaft needed about a 2mm packer on it to being the 48 and 24 geesr in line. Then you need to make sure your quadrant is staying square. The bolt on mine was bent as pulling things out of wack, so I straightened it, then it wouldnt line up with a slot...... so I bent it again . Then I made two ball and socket washers so the bolt could be tightened without twisting the quadrant. Seems to be working.. Need some pictures?

Stuart

[Sterob]

Did you either try putting the washer behind your smaller gear or just putting a washer there to pack it out a little.

I thought of that, but the bottom shaft is short, so packing it out would mean less of the key and shaft to support the 24T gear.

[Sterob]

Could the bottom shaft have been spacer (but in reverse to how you had it), washer then the gear?

I reversed the 'top hat' spacer but then it contacted the 127T gear. The only thing I could think of to do was to machine that lip off.( hoping that it was't critical to its operation )

The more I look at it the more I think it is a progression of poorly fitted parts.....I might have to pull it all down and 'fit' each component.

[Sterob]

I had this problem on my lathe(better late than never lol)
First thing you need to check as best you can is the output and input shafts are lined up. My output shaft needed about a 2mm packer on it to being the 48 and 24 gears in line.Stuart

So you packed the GEAR to bring them into alignment, not the shafts themselves?

Then you need to make sure your quadrant is staying square. The bolt on mine was bent as pulling things out of whack, so I straightened it, then it wouldn't line up with a slot...... so I bent it again . Stuart

I need to check this. It seems to be quite agricultural at the moment.

Then I made two ball and socket washers so the bolt could be tightened without twisting the quadrant. Seems to be working.. Need some pictures?

Stuart

I can't picture this. A pic would be nice thank Stuart.

The trouble is, I'm trying to do a job and then I have to stop and re-fit components on the lathe so it works the way it is supposed to so I can finish the first job......


"I remember when a '5 minute job' only took an hour....."



Steve

[Stustoys]

Here you go.
There is another washer set on the other side of the quadrant.
My lathe has metric leadscrew.
As you can see from the mark on the spacer there isnt much room. I think if you bottom the gears the 127 will rub.
Hope this helps.

Stuart

[Sterob]

Thanks Stuart.
I shall investigate and see what I have and don't have.


Steve