Need help from real machinists
- Thread starter alinwa
- Start date
I read this in the specs
I've heard it before
But I need to find out what it MEANS.
I don't have the tapping attachment.
If "power tapping" is just dropping the quill? Or driving down? Or, Or, Or......??...... We're talking 1/4-28 here....... and the few tappers I've watched in operation are slip-clutched/auto-reversing or, on the big ones I've seen them with a repetitive auto-reversing almost "roto-hammer" type vibrating action. I've tapped a few hundred thru-holes in 1/4 to 3/8 mild steel fabricating truck racks and such, using a cordless DeWalt Hammer Drill............but this blind sticky stuff has me snaffled as far as powering in.
Are you suggesting just run the tap loose in the collet or chuck? Or coast into a blind sticky hole and hope for the best?
Understand that I AM wikkid canny.... I haven't broken nor stuck a tap in years, but even though my fingers know how to not break even a 6-48 or a 4-40 gun tap, I'm just confused about HOW to do this in a blind hole? With no tapping head?
I ain't a piss-poor planner, I EXPECT perfect performance...
I've been drilling/tapping dozens of holes in 304 SS the last few days with no issues, keeping nice steady chips and curls (I checked though, even 304 does work-harden like a buggah!!) but it's easy stuff compared to whatever's in these recoil lugs!
I'm asking heahhh, I've just never dared power-tap a blind hole!
I don't have a tapping head. Those are useful when your machine cannot feed with a proper feed rate. Those tapping heads have lead screws to solve the problem.
It takes some practice, to get the feel for it. I tried to say in my earlier post that with through holes drill all the way through, and a blind hole drill 1.5 x thread depth at the very minimum. Use spiral point taps for through holes and blind holes drilled ~2x thread length. If the hole is deep enough to contain the chips a spiral point tab will suffice.
As seen in the video some leave the chuck loose which is about as good as the other, tap with a step mill if you can, and let the pulleys slip a little. Variable speed mills like the Bridgeport can snap off taps if the vs drive wants to wind up.
If you are worried about a shallow blind hole you can either use a spiral flute tap or even use a thread forming tap that does not have and flutes.
We power tap everything. we even tap with a large 3/4 inch Milwaukee magnetic drill drill in a pinch. It will drive a 1"-14 tap in steel.
Terry
https://youtu.be/LkbZPP8ErvU
https://youtu.be/I95YrmVUL18
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Something you wish to say? Speak up.
Do any of you guys remember Arnold Stang? His most famous quote is, "Chip, chip, chip!" ;-)
I always take extra care when posting on forums, because the reader doesn't have the benefit of seeing my facial expressions, or hearing my tone of voice. I reckon that's why smileys exist. ;-)
Peace, F1
I always take extra care when posting on forums, because the reader doesn't have the benefit of seeing my facial expressions, or hearing my tone of voice. I reckon that's why smileys exist. ;-)
Peace, F1
LOL!
I think he is saying "wasn't your Facebook" like "you're using someone else's material" but hey....... as you say....... got no real idea without clarification!
Or maybe he's saying "wasn't you in the video you Effing B!%#"
Or "Louis J Wasn't Your Fanboy?"
We Shall Soon Find Out
I think he is saying "wasn't your Facebook" like "you're using someone else's material" but hey....... as you say....... got no real idea without clarification!
Or maybe he's saying "wasn't you in the video you Effing B!%#"
Or "Louis J Wasn't Your Fanboy?"
We Shall Soon Find Out
cloudrepair
DWG
Al it sounds like some 316 stainless
And sounds work hardened with stainless I usually drill it 10 to 20 percent less than 1018 steel and increase feed by 5 to 10 percent if I have a good way to feed it consistently. Otherwise slow it all down maybe 30 to 50 percent and keep tool cutting or off the part.
With the blind holes I like the spiral flutted taps always. I think one of the things that get people is they slow down on the feed rate to much with stainless
If you are drilling it with hand feed it is harder to stay consistent and at a known feed rate.
Drilling about 1000rpm and feed about 3.7ipm
Oh don't use the center drill spot drill it with a spot drill with same angle 118 works fine but 135-140 better
I use a 120 carbide spot drill and 118 drills
And sounds work hardened with stainless I usually drill it 10 to 20 percent less than 1018 steel and increase feed by 5 to 10 percent if I have a good way to feed it consistently. Otherwise slow it all down maybe 30 to 50 percent and keep tool cutting or off the part.
With the blind holes I like the spiral flutted taps always. I think one of the things that get people is they slow down on the feed rate to much with stainless
If you are drilling it with hand feed it is harder to stay consistent and at a known feed rate.
Drilling about 1000rpm and feed about 3.7ipm
Oh don't use the center drill spot drill it with a spot drill with same angle 118 works fine but 135-140 better
I use a 120 carbide spot drill and 118 drills
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Years and years ago, at the nuclear plant, another fellow and myself stole some sheet metal and cut it into triangles for a swing set he was building. We thought that was the hard part and the next night we were gonna drill holes for bolting it all together. That stuff was fairly thin and the first hole went easily....but we burned up every drill bit we could find trying to drill another. The next morning I asked a machinist to drill the holes and he quickly drilled them while we were turning over the shift. Never did figure out why we had such trouble but I'm thinking now that the drill was running bassackwards.
jackie schmidt
New member
wilbur;80901 never did figure out why we had such trouble but i'm thinking now that the drill was running bassackwards.[/quote said:
Alinwa you pretty much covered it all on my behalf and really quite sad to see how Jackie was being treated. One would be hard pressed not only to find a nicer and more helpful Gentleman. He probably has accomplished more high end machine work and gained more knowledge than some here now seem to proclaim. And he was probably doing it before he even got out of high school so it rubbed me a bit raw.
JLouis
JLouis
dmort
Active member
Mike Bryant
Active member
Just out of curiosity I tested the hardness of a 1/4" tapered Pacific stainless lug this morning on my hardness tester. It tested Rockwell C 42. That sounds about right to me for hardened 416. I have no idea what stainless they use from their stainless lugs. I built a powder measure for myself a few months ago using a piece of 304 stainless for the body. There won't be another one of them, I guarantee. I went through more carbide cutters milling the flats on each side of the body and kept expecting to break a tap off in it every time I tapped a hole. It sure made the aluminum I had used on all the rest of them seem easy in comparison. I never have responded to this post as the title of it definitely left me out. Lots of difference between someone who has worked as a machinist all of their lives working with a wide range of materials and someone who has barreled a few barrels over the years. I consider the real machinists to be some of these guys who can practically make anything with a lathe and mill and pretty much think outside the box. Jim Farley comes to my mind in this regard. He is quite a machinist. If it wasn't for Jim, there never would have been the joystick front rest that has pretty well taken over the benchrest world. Quite a feat of thinking outside the box to make the first one of those.
That's me in a nutshell. I got 'er done, and I guess I should post a picture of what I was actually doing but I think I'll wait to see how the assembly SHOOTS before getting hasty with the pix
JerrySharrett
Senile Member
On most 300 series stainless steels we recommend tap drilling for about 60% full thread instead of the normal 75-78% of full thread.
Some 300 series like 303FM can go75%. Wait till you try some of the exotics like Hastalloy or Inconell!!!
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GeneT
Active member
Thanks Pete!
Thanks for the heads up! Here's the YouTube channel: https://www.youtube.com/channel/UCn4U3aEr6L2nLe1m_3as6JQ The guy is obviously d***ed good.
GsT
Thanks for the heads up! Here's the YouTube channel: https://www.youtube.com/channel/UCn4U3aEr6L2nLe1m_3as6JQ The guy is obviously d***ed good.
GsT
Mike Bryant
Active member
Jerry, I don’t know whether you ever met Joe Archer or not. We used to travel to matches in the GC and Midcontinent region from the 80’s to the Mid 2000’s or so. He works in a machine shop and has ever since they left Shamrock that uses a lot of hastalloy, inconel, and other exotic materials making medical valves. I thought he was going to get to shoot Seymour this coming weekend but snapped a rod in his back a few weeks ago and had to have it redone.
JerrySharrett
Senile Member
Mike, I never had the privilege of meeting Joe, and, 2018 I missed my first Shamrock. I had made them all from Shamrock1to now. To me the Shamrock was a great way to start a new BR season....i.e.will these new barrels shoot??
Hastalloy, Inconell, Waspally and many of the "Space Age" materials you get into working for a large chemical manufacturer.
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