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question about thread chasers

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Mutt

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#1

mmcmdl

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#2
No , you can't chase different pitches but you can adjust for diameter changes to a point . ( Limited by diehead ) Not sure why they would be marked .248 - 32 vs. 1/4 -32s . Maybe they marked the nominal major diameter instead of .250 ?
 

benmychree

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#3
When a die head is used very much over or undersize, the pitch changes; perhaps the exact pitch was important with that size of thread, I think, however, it would make little difference (in pitch) if the diameter is set at .250.
As an aside, some die heads can cut a range of diameters with the same chasers, the Landis die is one of them: the chasers are not angled like Geometric and are tangent rather than radial, because of this, chasers of different lengths can be used, and they can be sharpened (with care) on a ordinary bench grinder, and chasers from one set (of the same number) can be used in another set. The Jones & Lampson is another radial die, but it cannot be used for different diameters like the Landis and sharpening the chasers is a much more involved process.
 

Mutt

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#4
No , you can't chase different pitches but you can adjust for diameter changes to a point . ( Limited by diehead ) Not sure why they would be marked .248 - 32 vs. 1/4 -32s . Maybe they marked the nominal major diameter instead of .250 ?
I meant to say different threads. like using a 12-24 set of chasers to cut 10-24 threads
 

mmcmdl

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#5
Depends on your diehead adjustment range .
 

Mutt

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#6

mmcmdl

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#7
I have the exact head as well as some smaller heads . All Geometric . I have the chaser sharpening fixture and finishing gage along with it . I'm not positive of the adjustment range though , but it may be possible .
 
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benmychree

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#8
I doubt that it is possible to cut both threads with one set of chasers, I expect that it would change the lead.
 
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