Spiral machine tap test suggestions

[samthedog]

Ok folks, there was a discussion praising the virtues of the spiral machine tap. I have used SKF and Güring in the past but have been more and more impressed with Chinese offerings of late. I will be ordering a range of taps in various price ranges from China for testing so I need your help.

1. What price ranges for individual taps would you like to see? Keep this based on the price you would pay for a Chinese tap
2. What tap sizes would you like to see tested? Metric is easiest to find but imperial is also possible
3. What material would you like the taps to be made from? I can get high cobalt and regular HSS however cobalt will up the price

Let me know what you would like to see and I will try to accommodate this in the order and testing.

Paul.

 

[Ken from ontario]

I find the smaller taps more prone to breaking so I'd like to see the following sizes tested:
M3 , M4, M5, M6 in metric and 10-24,32, 1/4-20,24, 5/16-18,24. in imperial.
The price range should be less than $10 to $12 USD for HSS , that's what I paid for FMT Standard. it would be great if we could compare prices vs quality between HSS and other materials like Cobalt.
Please let us know your findings.

 

[David S]

I mostly use imperial taps in the range of 2-56 to 8-32. HSS has worked fine. I mostly work with aluminum and brass. Would like the lowest cost.

David

 

[samthedog]

Thanks gents. I am currently looking at ordering some digital torque wrenches so I can measure the torque required to cut the threads and compare the figures.

Looking forward to any further suggestions.

Paul.

 

[royesses]

Dial type torque-o meter would be a better choice for measuring torque to turn. Breakaway torque is higher than running torque and could have an effect on the test. CDI torque wrenches are what I use for setting rear end bearing preloads and breakaway torques.

Just thinking out loud. If this does not sound right just ignore.

Roy

 

[T Bredehoft]

Recent work I've done with torque, digital meters are too sensitive, they will read stationary pressure but fluctuate wildly on rotational torque.

Not dealing with torque, but I've been using 4-40 and 5-40 spiral flute taps in O1 and aluminum, there's quite a difference in the two. (metals).

 

[samthedog]

A way around this with the torque wrenches could be to measure the load on the drill press motor while tapping with a tapping head. This would give a pretty good indicator.

Paul.

 

[T Bredehoft]

If you could rig a small motor that would give a slow speed tap, so you'd have time to read the VOM. My drill runs 'way too fast for something like that. Same motor for all taps, same speed, too.

 

[samthedog]

If you could rig a small motor that would give a slow speed tap, so you'd have time to read the VOM. My drill runs 'way too fast for something like that. Same motor for all taps, same speed, too.

I was thinking of clamping an amp-meter to the drill press as my drill press will run at 100 rpm which is fine for tapping. I will just videotape the load so I can replay it to see what the peak load is. This should give me a good idea of which taps cut with least resistance.

Paul.

 

[Z2V]

Your amp meter might have a peak/ hold feature also. It will lock on the peak amperage.