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Thread: HIGBEE THREAD CUT CYCLE
12-13-2002, 10:55 PM #1
Would anybody like to know how to make a National Standard Fire Hose Coupling and deburr the first thread so that that first fin is gone and the possibility of cross threading is gone?
"Higbee Cut" is a true process and is in the machinist handbook in the National Standard Fire-Hose Coupling Screw Thread.
If you are making a high priced part and you want to impress the customer this will do it!
12-13-2002, 11:22 PM #2
My boss always makes me 'Higbee' the first thread, no matter what we're making.
12-14-2002, 09:30 PM #3
Pal, Im all ears & eyeballs and I bet there's more where I came from. Please give us a demo!! Thanks,
12-14-2002, 11:55 PM #4
I will try my best to explain how it is cut.
First what you want to acheive is to remove the part of the thread which is usually a small fin on the turned 45 degree angle portion of the part blank up to where it is a full profile 60 degree thread form.
To do this you use a grooving tool after you are done with the threading cycle. First off you must calibrate your threading and grooving tools to the face of the part (or zero.This is where an important trick lies hidden. The center or tip of the threading tip has to be calibrated so it is equal to the leading edge of the groove tool and the groove insert must be as wide or wider than the base of the thread form (an 1/8" wide insert will work up to 8 pitch. etc) Lets say you are doing 10 pitch threads 1" thread length. Now with your regular threading cycle when you program your length you will get 1 full inch of thread and your first full thread length will be z-.100" (a starting length to be deburred) Now program your grooving tool(also in the same threading cycle as used to thread with) to a depth of z-.100" and you are starting to get a deburred thread. You will only need a couple of deburring passes to remove the burr (so play with the starting x value). But there is more to explain !! Spindle rpm and the machines rapid traverse rate will determine the amount of angle of ramp on the deburred thread. The machines rapid rate will stay constant so for a squarer ramp run slower rpms and a tapered ramp more rpms. Only one more tip if after calibrating the tools you have to adjust the z length of cut you must offset the z length equally on both tools.
Please rate me on this I would like to know how many people I just trained and if I'm any good at it!!(make this a hot site)
12-15-2002, 02:18 PM #5
Pat, thanks for the good info,not an easy operation to describe with just words and no pictures.We normally leave a 45 plus a little bit of the minor diameter to the + side of the start thread but the higbee cut looks WAY better. might be a tricky deal on a manual lathe with no stop mechanism but Looks like cake on cnc. I looked around the shop and found a coupler that shows exactly what it should look like.Now ..... if I can just make this link work!! http://photos.msn.com/myfiles/folderview.aspx?Folder=4gPozhciq6ZTdypEPFXEQi ctJ*RhGuXgXweAIQIykiw%24
[This message has been edited by sasbenson (edited 12-15-2002).]
12-15-2002, 04:01 PM #6ufscrap Guest
I have found the G32 threading cycle to be perfect for stuff like this. G32 allows you to control the tool anyway you want to under a threading feed. In the manual for my Haas SL-30 the example is a continuous thread that goes from straight to tapered, then back to straight (I'd be interested to see the nut for this screw). With G32 you can change the vary the pitch while threading. I can't think of an application for this, but it might come in handy sometime. We use this cycle all the time for higby ends, and for taking the spring out of long threaded parts. In other words, you can program a thread that moves the tool into the piece at a variable taper rate to compensate for deflection.
Your method was described well, and I am sure it works well. The only problem I have is my operators often override the rapid speeds on new jobs, and that would make for a bad end.
12-15-2002, 06:51 PM #7
ufscrap...there are different types of "augers" where the lead of the "flights" (probably not the right term) changes. Also, have seen types of feed rollers, I don't know what for, that had spiral grooves in the O.D. that increase/decrease in pitch along the length of the roll. Not sure how these were made, but maybe the G32 would work??? Some of them are obviously milled.
05-03-2006, 09:50 AM #8
In regards to the Higbee Cut on fire hose couplings it should be noted that the first thd is completely removed and the Higbee Cut starts on the second thd.
05-03-2006, 11:31 AM #9
At one time I could really have used a method for getting a Higbee on a lathe. We milled thousands of them on a CNC Bridgeport - not the fastest of all possible methods.
05-03-2006, 06:03 PM #10Please rate me on this.
05-04-2006, 12:20 PM #11
I will try to get you a picture of it, they work great. With all the numb nuts that are in my fire department, it is very, very, extremely rare that anything gets cross threaded.
They actually have a mark on them too where the thread starts engaging. Pretty neat.
06-19-2011, 09:53 AM #12
02-26-2017, 01:42 AM #13
Hi, I really want to try this on our Haas TL1, you say I have to do this in G32 so that I can control the tool
Change in the threading cycle? Would this be possible on a Haas TL1 as the spindle has to stop in order to tool change.
Someone be so kind to upload some example NC code as I am having a hard time picturing the code
02-26-2017, 05:19 AM #14
G76 X... Z-(1 lead) K... D0500 A0 F...
Add +.150 to your groover Z offset if it's not synced with the threader &work your way in.
Leave Rapid at 100%. As was said, rapid & spindle speed will affect length of the pullout
02-26-2017, 07:04 AM #15
We routinely did first AND last thread Higbee / blunt start on every acme thread we cut.
02-26-2017, 08:05 PM #16
Somewhere in the dark recesses of the past Pi had a real good explanation of how to program this..
02-27-2017, 12:50 AM #17
This is a great method. Tried and true for sure. Though "higbee" calls for a specific radius in relation to the size of the thread. This will just give it a "blunt" start, which is often more than sufficient for any customer. But if "higbee" is called out, there is inspection criteria.
Thanks for sharing pal!!