1000 RPM too much for tapping steel?

[kendo]

OK, cold rolled 1018
hole drilled thru 1/2" steel with Morse #7
OSG hy-pro spiral point 1/4-20 tap, destroyed
using regular coolant (cim-cool) like always

float tap:
1000 RPM
F45.

rigid tap:
1000 RPM
F50.

We used to run this program at about half the speed with cheap china made taps and would run all day

Now we got good taps and I thought 1000 RPM would be no problem. I hear a lot of folks use 1000 as a standard since it makes feed calculations so easy.
The taps are breaking though, and sometimes the threads look like garbage, all chipped and hard to screw in. When the taps break, theres srtrings of chips jammed in beside the tap and hanging out the bottom of the through hole.
So it looks like 1000 is too fast for the chips to push ahead of the spiral point.

Sound about right?
sure surprises me...
backing it off to 750rpm for now

[Geof]

Have you tried spiral flute? I know it is not needed with a through hole but I frequently tap 1018 both HRS and CRS at 1000rpm both 1/4-20 and 3/8-16.

I do use 13/64" drill and off hand don't know if that is larger or smaller than #7.

[kendo]

I tried a spiral flute we had on hand
it broke instantly
3 flutes though, makes it a lot weaker tap I think

the 13/64 is .203
#7 is .201

problem is we ran the #7 all this time, no porblem til now

[kendo]

I found the speed and feed recomendations for the OSG tap
in 1018 it says cutting speed of 25-50 FPM
thats 764 RPM max for a .25 tap

[cam53]

I been using GREENFIELD taps running at 1246 RPM's using a G84 G95 cycle seems to work better than G94,plus you only have to change the RPM'S if you need to slow it down.Always center drill a diameter larger than .250 for chamfer.One machine we had there was a lose drive belt,with some slack that caused us to run slower RPM'S,to keep from breaking taps.