how can i improve the finish of my bbl threading
- Thread starter rsmithsr
- Start date
Butch Lambert
Active member
I believe that is what he is saying.
GeneT
Active member
Yes, I meant a slightly undersized (relative to the thread nominal major diameter) tenon. Thanks for clarifying.
GsT
this was very true when people GROUND THEIR OWN TOOLS.
which was how i started. today i grind very little.
most is available over the counter.
which was how i started. today i grind very little.
most is available over the counter.
Rubicon Prec.
New member
The flank side does do something. Even at 30*, it still cuts the amount you infeed. At 29.5*, the flank side cuts full depth, but it tapers out. The leading side cuts the full depth on each pass regardless of the angle.
'SPLAIN that to me ?
how does moving a cutting tool to the LEFT at 29.5* cut on the right ?
the 29.5 is a angle cut, not a straight in plunge.
how does moving a cutting tool to the LEFT at 29.5* cut on the right ?
the 29.5 is a angle cut, not a straight in plunge.
Rubicon Prec.
New member
Because it’s a form tool. If you infeed .005” at 30*, the right side of the cutter absolutely cuts that amount. The rest of the tool above that on the right won’t be cutting because previous passes have already removed that material.
Infeeding at 29.5* is closer to straight in so the entire right side of the cutter will be cutting, although nowhere near the amount the left side is.
Now if you were feeding at less than a thread pitch, say .005” ipr, then the right side would not be making contact at all since there’d be no material left to remove.
sorry but if you move a tool in to the left, the tip of the tool will remove metal as will the left side.
the right cutting edge touches nothing as the tool is always moved in to the left. the tip is cutting what was there but now gone...never the right side
go do it and watch. feed the tool at 29.5* never a straight plunge.
the right cutting edge touches nothing as the tool is always moved in to the left. the tip is cutting what was there but now gone...never the right side
go do it and watch. feed the tool at 29.5* never a straight plunge.
Rubicon Prec.
New member
What gives the right side the shape if nothing touched it?
Dave Tooley
Active member
Pretty simple
30 degree infeed the right side runs parallel to the tread face. Theoretically it doesn't touch except for extending the right face the depth of the infeed.
29.5 very slight infeed into the face of the thread on the right side
As the infeed angle gets smaller you increase the cutting depth on the right side. At zero you would be cutting evenly on both sides.
30 degree infeed the right side runs parallel to the tread face. Theoretically it doesn't touch except for extending the right face the depth of the infeed.
29.5 very slight infeed into the face of the thread on the right side
As the infeed angle gets smaller you increase the cutting depth on the right side. At zero you would be cutting evenly on both sides.
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the tip of the tool
Rubicon Prec.
New member
The right side of the tip, right? The right side, equal to the amount you infeed, right?
"Modified Flank infeed
Generally, modified flank infeed is almost similar to the flank infeed method. The only difference is the angle. It has a lower angle than 30 degrees. Here the advantage of using this method is that it eliminates the risk of inserting the thread to the trailing edges. After the study and research, it is acceptable and guaranteed to get the best results of cutting thread with this method. It has 29½ degree angle infeed that practices the best way to cut the thread between 25 to 29½ angles. "
https://www.lathezone.com/how-to-cut-threads-on-a-lathe/
Generally, modified flank infeed is almost similar to the flank infeed method. The only difference is the angle. It has a lower angle than 30 degrees. Here the advantage of using this method is that it eliminates the risk of inserting the thread to the trailing edges. After the study and research, it is acceptable and guaranteed to get the best results of cutting thread with this method. It has 29½ degree angle infeed that practices the best way to cut the thread between 25 to 29½ angles. "
https://www.lathezone.com/how-to-cut-threads-on-a-lathe/
Am I to assume that most of this discussion involves using the compound to cut deeper? I thread straight in since I started using a proximity stop. Trying to use the compound caused it to cut a couple thou closer to the headstock with each pass causing issues unless I made a chicken groove.
yes it will...you are moving in on each cut...while a straight plunge does not.
can you back out your stop at each cut ??
can you back out your stop at each cut ??