Micro 100 threading tool

JRaut said:
I think @Mitch Alsup is talking about the so-called Helix Angle of the thread.

A (for example) 4 TPI thread looks something like this: \ \ \ \ \ \ \ \ \ \
Compared to a 50 TPI thread, which looks more like this: |||||||||||||||||||||||||

Not only are the threads spaced closer together on a 50 TPI thread, but they are also more 'upright' (i.e., closer to 90*), if that makes sense.

I still need to think about the relief angle thing though.... seems if you're using the method where you infeed using a compound set at 30-ish degrees, the relief angle on the 'back side' of the tool is immaterial.
Click to expand...

Since we’re getting down to the atomic level nitty gritty of thread helix angles, I’ll point out that not only do threads of different pitch have different helix angles, but threads of the same pitch but different diameters also have different helix angles. For instance, a 10-24 thread will have a greater helix angle than a 3/8-24 thread. Just thought I’d add to the confusion. ;)

Tom
 
Oh, okay, you were referring to the Helix Angle. If that is the case, then yes, the helix angle of tiny threads is very small. Relief angles under these circumstances are not a major issue because even small amounts of relief should be adequate for clearance on either flank. However, none of this has a bearing on the issue the OP raised, which is why the same nose radius by the same maker is okay for up to 76 tpi for some bars and not okay beyond 40 tpi on the bar in question.

The nose radius determines the shape and size of the root but unless we are talking about class 3 fits with a precision bolt being fitted into the internal thead being cut, the root is unlikely to be all that critical. Personally, I would just buy the bar under discussion and try it; I bet it will work.

Or call Micro 100 and just ask them.
 
I bought the Micro 100 tool in my OP. It cut the M22x.5 thread without any issues. Whether or not the thread is technically perfect, I don’t know, but the required depth was within my predicted range, and everything mates up nicely.
 
For the record, M22x 0.5 taps are less than $15, free shipping on eBay.
 
Make a holder for it and heat shrink the Bar inside.... You can probably cut the whole thread in one pass.....

www.ebay.com

1 Micro 100 Boring Bar IT-080350 Threading Carbide Bar | eBay

Find many great new & used options and get the best deals for 1 Micro 100 Boring Bar IT-080350 Threading Carbide Bar at the best online prices at eBay! Free shipping for many products!
www.ebay.com


  • Shank Dia.: 1/8"
  • Item: Threading Tool
  • Finish: Uncoated
  • Projection: 0.0200"
  • Cutting Direction: Right Hand
  • Hole Dia.: .080"
  • Material: C2 Micrograin Carbide
  • Max. Depth: 0.350"
  • Overall Length: 1-1/2"
  • Style: Internal Threading Tool
  • Radius: 0.0020"
  • Shank Material: Carbide
  • Cutter Material: Carbide
  • Center to Cutting Tip: 0.0180"
  • Shank Type - Machining: Straight with Three Flats
  • Min. Hole Dia.: 0.0800"
  • Measurement System: Fractional Inch
  • Max. Threads per Inch: 76
  • Included Angle: 60 Degrees
  • Thread Standard: ANSI, Metric 60 Degrees , UN
  • Offset Point: 0.0120"
  • Cutting Application: Threading
  • Min. Teeth per Inch: 40
  • Finish - Machining: Bright (Uncoated)
  • Max. Hole Depth: 0.3500"
  • Thread Direction: Right Hand
  • Features: Corner Radius Profile, Polished Split Face for Improved Edge Retention and Chip Evacuation While Reducing Galling, Split Geometry Makes the Tool as Rigid as Possible
  • Series: IT
  • Split Length: 0.060"
  • Neck Dia.: 0.0550"
  • Groove Width: 0.0380"
  • Max. Bore Depth: 0.350"
  • Offset: 0.012"
  • Min. Bore Dia.: 0.0800"
  • Item Type: Threading Tool
  • Brand: MICRO 100
  • Manufacturer Part Number: IT-080350
 
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