Shop Doc Forum » General Questions

1. Anonymous
   Unregistered

   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

   Posted 1 year ago #

2. Anonymous
   Unregistered

   I use 700rpm /35.0 feed in a blind hole stainless operation. It used to work fine with regular coolant. I switched to a synthetic and now I break taps all of the time and need to use a tapping fluid.

   Posted 1 year ago #

3. Anonymous
   Unregistered

   I've found that 1018 can vary a lot. One bar might tap just fine at 1000 rpm and the next bar eats up taps.

   I typically keep it at 700rpm or less in 1018 just to be safe.

   Posted 1 year ago #

4. Anonymous
   Unregistered

   No you should be using a constant feed rate for a given group of tap sizes and change your rpm, not a constant speed that won't work. Just as simple to figure out (constant feed rate X the pitch)

   Posted 1 year ago #

5. Anonymous
   Unregistered

   What make and type of machine? Did you ask OSG? Some tool sales companys have Application Engineers on call to troubleshoot this type of question and can even suggest faster production or better tool life solutions. Kennametal for instance has a phone number that can help...
   North America:
   Toll Free: 800.835.3668
   Fax: 724.539.6830

   Good luck!
   Steve

   Posted 1 year ago #

RSS feed for this topic

Reply

You must log in to post.