Need Screw Thread Pitch Information

GarageGuy

GarageGuy

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I'm almost finished building my radius turning tool, and it is time to mount the carbide insert. I'll need to drill and tap a hole to mount it, but have not had any luck finding any reference to the screw size or pitch.

The insert I'll be using is a VCMT 160404-PM5 made by Walter in Germany. The screws that I use to mount my TCMT 32.51 inserts fit perfectly, but I don't have a metric thread pitch gauge that is small enough to measure it. I measured the outside diameter of the screw (on the threads) at 3.85mm. Can someone educate me so I can order the proper tap? Thank you!

GG

VCMT.jpg
 
I suspect it is a 4mm nominal size. Standard pitch is 0.7mm, fine is 0.5. Very roughly, in case you have the Imperial pitch gage, the 0.7 is close to a 36 TPI, and the 0.5 is close to 50 (closer to 51 actually).

Perhaps someone can confirm this.
 
My Starrett #155 Imperial thread pitch gauge only goes down to 32 TPI. I'm striking out with all of my measuring tools today. :grin:

GG
 
Time to get out a mm scale and a magnifier.:)
 
All my 32.5_ screw down type inserts use M4 x 0.7 pitch T15 torx screws. Industry p/n TS-4.7-. Length varies depending on your tool shank size.
 
Excellent! That's exactly what I needed to know. Thank you! :encourage:

GG
 
GarageGuy said:
I'm almost finished building my radius turning tool, and it is time to mount the carbide insert. I'll need to drill and tap a hole to mount it, but have not had any luck finding any reference to the screw size or pitch.

The insert I'll be using is a VCMT 160404-PM5 made by Walter in Germany. The screws that I use to mount my TCMT 32.51 inserts fit perfectly, but I don't have a metric thread pitch gauge that is small enough to measure it. I measured the outside diameter of the screw (on the threads) at 3.85mm. Can someone educate me so I can order the proper tap? Thank you!

GG

View attachment 104173
Click to expand...

A 4mm external thread diameter is 3.978mm to 3.838mm OD so you have a 4mm screw. Can't tell from the pictures but it could be either 0.5 or 0.7 pitch thread. Those are the only standard pitches I found. Instead of a pitch gauge if you have a metric scale/ruler you can measure the thread pitch.

Hope this helps.

Tom S
 
TomS said:
A 4mm external thread diameter is 3.978mm to 3.838mm OD so you have a 4mm screw. Can't tell from the pictures but it could be either 0.5 or 0.7 pitch thread. Those are the only standard pitches I found. Instead of a pitch gauge if you have a metric scale/ruler you can measure the thread pitch.
Click to expand...

Thanks Tom! I don't know if I own enough cheater glasses to stack up so I could measure it with a scale. I was having a hard time with the thread pitch gauge on the smaller sizes with 1.5 and 2.0 cheaters stacked together. :grin:

GG
 
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