Tap Life

OK, here's a question for all you guru's out there.
I'm tapping 5/8-11 holes, in 4140 annealed, with HSS Steam Oxide coated
taps, with coolant. (cnc machine) I need to use a H7 rating, because the bars will be heat treated afterwards. To get any other tap would be 3 weeks out, and I can't wait that long. so I'm married to the above tap.
What type of tool life should I be getting?
atm, I'm getting roughly 250 holes and seeing a nice amount of wear on them.
I'm running the tap 300RPM @ 27.2727 IPM , roughly a 50SFM
Any suggestions on getting a better life out of them?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

http://www.intercononline.com/jokisch/econo897.htm
--


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
over a barrel wrote:

That stuff is great.
--

John R. Carroll
www.machiningsolution.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes even amazing IMO
We have a 1/4-20 in 4130 ~ 42rc that we do regularly and was getting maybe 10 holes with a nice hypro black before the tap would go skreek--now pretty sure its in the hundreds.
--


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
tnik wrote:

Why not use a thread mill? You could even cut the threads after heat treat then if you wanted.
--

John R. Carroll
www.machiningsolution.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John R. Carroll wrote:

I could thread mill, but no one carries a h7 thread mill in stock. Would be too far out. Plus there are 3,000+ bars to do, each bar with 15 holes.
and they already found out where the holes need to be drilled so their in the right spot after heat treat.
as for using a tapping fluid, I was trying to not have to do that..
So basically you guys are saying that no matter what, to get better life out of my tool, I have to use a tapping fluid/paste..
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
tnik wrote:

Sounds like it. You might try messing with the coolant concentration. What are you using?
--

John R. Carroll
www.machiningsolution.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thread mills don't come in H limits, one size fits all. You control size by using cutter comp.
--


Regards,
Steve Saling
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Garlicdude wrote:

LOL I'd forgotten that, or just didn't know. I've never bought a thread mill by specifying anything but the pitch and sometimes internal/external or both. I'd think a 5/8' diameter would lend itself to an inserted cutter body that would get yuo a range of pitch's with different inserts.
--

John R. Carroll
www.machiningsolution.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 1 Oct 2008 09:45:37 -0700, "John R. Carroll"

========see http://www1.mscdirect.com/CGI/N2DRVSH?PACACHE0000070408919
priced 135 to 362 $US each. Spicy meatball compared to a tap, but....
Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Garlicdude wrote:

Ahh ok.. didn't know that.. Just knew to get a different coated tap it would be 3 weeks out..
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Question:
do you replace your taps before they're expected to break or after they've broken ? how much time do you lose getting them out when they break in the part ?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@gmail.com wrote:

We are replacing them before they break.. We noticed a nice amount of wear after about 250 holes.. We could probably push it more, just don't want to spend the time getting a broken tap out.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

How about regrinding? Properly done the taps will cut H7 for a long time. Skip the coating and work out a swap arrangement with the tool grinder.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

thank you for your reply
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John R. Carroll wrote:

It's called Blue Cool S2420
and using the recommended concentration 2.5 - 4 from the manufacturer.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

most manufacturers recommend the max for tapping, are you at 4%?
Thank You, Randy
Remove 333 from email address to reply.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

========Yes, but the trade off is longer cycle times.
If possible slow the tapping speed down further, and/or add a block where the tap moves over and is dipped into a container of HD tap compound just before it taps every hole. [Remember to turn the coolant off so as not to wash the tap lube off the tap] This may contaminate your coolant if you are running water soluble. It may be possible to use a very "rich" mixture of your current water soluble coolant to eliminate contamination, or at least a water soluble tapping compound to avoid tramp oil.
Some extra heavy duty tapping compounds you may wish to consider are http://www.cimcool.com/cgi-bin/merchant2/merchant.mv ? CimTAP 401 looks promising. http://www1.mscdirect.com/PDF/2008/581837.pdf
Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Very cool!!
I think, tho, solubility with the existing soluble oil may be a double edged sword. Altho a miscible tapping fluid would seem to be an important property in a soluble-oil system, it could, conceivably, detract from the intended properties of the reservoir soluble oil.
Otoh, a tapping fluid non-miscible in soluble oil would by definition not mix, and then could conceivably be recovered by a skimmer, and thus prove to be especially economical.
Just thinking out loud....
--
PV'd



[Remember to turn
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
DrollTroll wrote:

Yea, boss doesn't want to go that route.. says it will add too much time to the operation.. well.. that and if the operator isn't watching, KA-POW!!!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.