AL960b metric threads not quite right

[Machtool]

How did you come to that opinion,a detailed description of the method used is still waiting to be seen.

From post #1.

I am cutting threads in a bit of a 'unconventional' way as I am threading up to a shoulder and the lathe doesn't have a foot break. I have an internal threading bar coming onto the back of the work and running it in reverse so I can leave my half nuts engaged.

Isn't he wittling away with the tool at the far / back side of the work? Which will work, surely it has to be a gear train issue, or settings of the Quick Change Gear Box. He said in post #1, he is leaving the half nuts engaged, so that rules out metric / imperial screws, if the correct translation is happening in the gear train?

[pipeclay]

Possibly but I wouldn't like to give an opinion of a possible cause until a detailed description of this method was presented.

[Machtool]

Possibly but I wouldn't like to give an opinion of a possible cause until a detailed description of this method was presented.

True that. I couldn't possibly express an opinion, until I know the torque he did the nuts up on the gear train qaudrant nuts.

[pipeclay]

I don't think that the torque of nuts in the gear train would be a factor in this problem as the gears in volved would be idlers and keyed change gears,if the torque is a factor then the question might be why wont my leadscrew turn or why doesn't my spindle turn .

[Wilson85]

Hello Everyone,

Sorry for the time taken to reply. Have had a few things going on.

Well a few people have guessed it. I had one of the 40 tooth gears in the wrong spot...... I left it on the 127 tooth gear when it was supposed to be on the 120 tooth gear. Feel like a bit of a boofhead but unfortunately you get that sometimes... Once everything was in the right place, I cut a beautiful 2mm pitch thread.

I have enjoyed reading the conversations about threading up to a shoulder and have learned a new word... Pontificate!

Thank you to everyone for the help and suggestions.

Cheers
Anthony

[Stustoys]

Good to hear you have it sorted Anthony

Dr. Google tells me Tieri Qld is 220Km inland - West of Rockhampton. He might have bigger issues to deal with at the moment.

Well I was thinking of things less dramatic but yes that was the idea. Hope the water at RC's is on the way down now with no major damage done.

Stuart

[janvanruth]

How did you come to that opinion,a detailed description of the method used is still waiting to be seen.

1 he keeps the halfnuts closed at all times
2 the threads are fine but the pitch is off
3 he is plunge cutting using the compound feed, set to 0 degree