MetalworkingFun Forum

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

(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.

You sure got a nice finish on that 1018 steel.

Ed

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.

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

(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.

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

(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.

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.

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.