Internal Acme threads

[JonP]

O k so I've cut a Brazilian threads on QT 15 with T32 control but now for the first time I need to cut ID acme threads they are 2.25 X .3 pitch ,cutting them in 12L14 , I'm kinda nervious cutting this course and acme to boot. So I am asking for some words from the wise, like sfm, how many passes, should I set angle to 28 degrees? Any other comments welcome thanks, Jon P

 

[dcsipo]

O k so I've cut a Brazilian threads on QT 15 with T32 control but now for the first time I need to cut ID acme threads they are 2.25 X .3 pitch ,cutting them in 12L14 , I'm kinda nervious cutting this course and acme to boot. So I am asking for some words from the wise, like sfm, how many passes, should I set angle to 28 degrees? Any other comments welcome thanks, Jon P

i would think the the angle should be a little less than 1/2 of the angle between the side walls...like 14[SUP]o[/SUP] since the full angle is 29[SUP]o[/SUP] 12L14 is piece of cake. The rule of thumb 150sfpm with HSS and with carbide, 400-500sfpm, could go maybe 25% faster, but not much more...

ACME General Purpose Thread Design Calculator | Engineers Edge | www.engineersedge.com

dee
;-D

 

[michiganbuck]

Id threads are difficult to measure.. I like to have or make an Od thread to be used as a test gauge..

 

[JonP]

Thanks for the reply and I do have a piece of the male threaded part to check my fit thanks again. Jon P

 

[Philabuster]

i would think the the angle should be a little less than 1/2 of the angle between the side walls...like 14[SUP]o[/SUP] since the full angle is 29[SUP]o[/SUP]

On a Mazak, the angle used is the total thread angle. The machine will then feed in half of what angle you designate.

You would put in 60° if you want to cut down the side of a standard thread and 0° if you just wanted to plunge feed it and cut with both sides of the insert, or use some angle in between for modified flank cutting.

 

[dcsipo]

On a Mazak, the angle used is the total thread angle. The machine will then feed in half of what angle you designate.

You would put in 60° if you want to cut down the side of a standard thread and 0° if you just wanted to plunge feed it and cut with both sides of the insert, or use some angle in between for modified flank cutting.

Ah, that is news to me ...but sounds like a neat feature, like a direct read dial on a manual lathe, not travel but material removal.


dee
;-D