Power tapping test results

[Mayhem]

Cool video Ken. I bet Brian is glad his door was closed

[PixMan]

(03-30-2015, 06:03 AM)Mayhem Wrote: Cool video Ken.  I bet Brian is glad his door was closed

LOL, thankfully wasn't home and the only evidence remaining that I did anything is the half a block of steel with half a hole. That'll be another one of those pieces gathering dust until I need to saw it into smaller usable chunks.

I'll have to show him the video though, so he can know more about with that machine he walks by a few times a day can actually do.

[EdK]

You sure got a nice finish on that 1018 steel.

Ed

[PixMan]

Ed, that's really easy to do with carbide insert tooling. The key is to run it with some speed, get some heat in the chips.

[DaveH]

Ken,
Nice video  

Ken, if you reduced the depth of cut to say .020" or .010" would you keep the spindle speed and the feed rate as it was?

 
DaveH

[PixMan]

(03-30-2015, 08:54 AM)DaveH Wrote: Ken,
Nice video  

Ken, if you reduced the depth of cut to say .020" or .010" would you keep the spindle speed and the feed rate as it was?

 
DaveH

Actually I did make a finish pass at .015" deep but didn't change speed or feed, which I should have done. You can see in the later photos of the opened hole that the shiny, reflective finish seen in the video is gone and that's why.


I should have upped the spindle speed from 730 rpm to at least 1000 for that to get some heat back into the process.

[Mayhem]

Yesterday I needed to tap a 1/4-28 thread into the end of a shaft. I have never power tapped before because I only have straight flute taps. However, Russ gave me some spiral point taps when I was in the US last, and one of them happened to be 1/4-28.

I followed Ken's process of determining a safe depth and away I went. I cannot see myself buying straight flute taps again. Power tapping is awesome

[PixMan]

(04-05-2015, 10:33 AM)Mayhem Wrote:  I cannot see myself buying straight flute taps again.  Power tapping is awesome

Same here. Excepting the occasional special tap (screw thread insert, Acme, etc.), I will use only spiral point (through holes) or spiral flute (blind holes) for tapping, even when tapping by hand. Those are always seem to be good HSS or HSS-E (5% cobalt), and are just plain stronger than high carbon steel hand taps.

A few days ago I had to tap a blind 5/16-18 in steel, but had no spiral flute. I used a spiral point tap in the lathe, but did only start it under power and finish with a tap wrench.

The 5/16-18UNC H3 spiral flute tap is on it's way now. I'll be adding a few more too, but not much over 5/8" taps. Beyond that I can single point thread them.

[Vinny]

I bought a tapping head last year and had a few spiral point taps already (got them in a lot off ebay). Rather than buying t-slot nuts I decided to make some. When it came to tapping them I used a 3/8-16 spiral point and that part of the job went real fast. Now I find when I need a tap, that's the first thing I look for.

[PixMan]

When you make T-nuts it's a good idea to NOT tap them clear through, I don't know if you did. Good for you if you didn't.

The reason is that if the stud goes through and bottoms out in the T-slot, too much torque on it can force the T-nut up and blow right through the machine or other device's T-slot. I have a few T-nuts that are homemade (not by me) but haven't had that problem, but having seen it I'm thinking I may be just lucky.