Should I use a floating holder for rigid tapping?
It is helpful in some applications but not needed in most situations. Most of the time floating tap holders are nice when you are using a small tap and the slightest misalignment and/or feed error can break the tap. Also if your drill walks the floating tap holder will allow the tap to follow the hole ( to a limit).
In three years running Fadals, I never used a floating holder; no problems, with taps down to 0-80. As fmari says, if your machine has accuracy issues, they could help.
I thinkthat they would have more application in a lathe. Unless your sure that your turret is dialed in axially 100% and that your X offset is perfect - a floater can be nice.
A mill that uses the tools C/L as a locating point instead of a spindles C/L would have much better tracking.
Sometimes I will run rigid and intentionally alter the X value offset in my lathe to git a +.005 hole from an H3 tap. LOL!
Think Snow Eh!
I dunno, is it me? Seems like "floating holder" and "rigid tapping" should never be in the same sentence. An oxymoron; kinda like "Senate Intelligence Commitee" or "United Nations Sanctions".
Rigid tapping=zero pullout
When the spindle is reversed, rigid tapping comps the lead and comes to a brief rest prior to reverse and withdrawl. Floating holders have a certain pullout distance in Z while the spindle comes to rest and reverses.
OX is dead on with the lathe for floaters-on center (or slightly off center). Rigid tapping on a lathe should only be done with live tooling and off center.
RAS, what material you running in the Fadal? Can you post a sample of the rigid tap in the Fadal that works best for you? Seems like around here, hand tapping after a brief start from the Fadal is king. Mill guys have sore elbows here.
Mostly aluminum, the 0-80 was in PEEK, some stainless and 1018. When I first started on the Fadals, finishing by hand was also the norm; I just didn't see any sense in that, with thru holes. I talked the company (finally!) into buying some roll form taps, and then blind holes were also tapped to depth. Typical program for a 4-40 (roll form) thru 1/2" aluminum plate:
T10 M6 (4-40 ROLL FORM)
G0 G90 E1 S2000.2 M5 G80 M90 X1. Y-1.
H10 Z.5 M8
G84.1 G99 R.5 Z-.6 S2000.2 F50.
G0 G80 Z3.M5
There is just no good reason to hand tap, if you can let the machine do the work. I know, where I worked, "that's the way we've always done it" was the 'reason'. After I showed the other CNC guy that it was possible to tap to depth, THAT'S the way we always did it... Of course, there are exceptions, when it's better to finish by hand (blind hole; can't drill deep enough for chip space, and a cut tap is all you have).
When you say "float" do you mean radial float or axial compensation? Keep in mind that there are tap holders with radial float for misalignment issues and then there are the tension/compression tap holders for spindle/feed/pitch problems.
I've said this before.
If you add up all the tolerances in the machine components when that spindle stops at the bottom of the hole and reverses all kinds of weird things *can* happen. Many times the tap drags, the threads stretch, etc. Some machines rigid tap better than others. Haas seems to have it down pat. Fadal owners in my area? It drives them nuts.
Many owners such as RAS never have a problem. The point I'm trying to make is this: It just depends on your machine and how it acts.
I've used floaters in rigid applications, mostly in graphite where the slightest mis-alinement between spindle/z axis can result in a fractured thread which then pulls out when someone does the bolt up to the right torque.
but I've never had a problem with tapping rigid even down to 1.5 mm metric threads (.060" dia old style ) and thats running the spindle at close to maximum tapping speed (3500 rpm)
Come on, I rigid tap with my sl-10 all the time. The last one was a 6-32 tapped hole with .5 depth of the thread. This was with a thread roll at 1000 rpm held in a er32 collet chuck.
Rigid tapping on a lathe should only be done with live tooling and off center.
We use the floating holders still, even though we have rigid on all of our machines, if the thread depth is not critical. I think they do not force the tap to start as accuratly and the only reason we still use them because we still have a half a dozen of the holders and with 6 vmc's we run short of tool holders from time to time, hell you can put 25 in each one and some jobs need that many or more.
Kustomizer, I would to help you with your holder problem.wink.
Hello...roll form is entirely different from actually tapping with the true tap drill size.
RAS, thanks for the info...I've brought up the form tap a few times, and recently the Fadal guys tried it. Wow, it worked in 4140. We'll see if the new trend continues.
Edster, I'd like to see that sl-20 rigid tap the 6-32 holes with a GH3 in M7 tool steel on a 2500 part run and a 38 sec cycle time and auto load bar feed. It doesn't take long for the spindle to get hot enough to be "off-center" and snap. What if you couldn't use a roll tap due to application of the part? Also, that sl-20 may be a hogger, but she ain't no precision machine...no offense.
No worries, I guess I should get a floating tap holder because my sloppy machine has no problem rigid tapping [img]smile.gif[/img]
Btw, I used the roll tap because I had to have at least .5 of thread and wanted to do it in one shot.
Frank, I don't see an er32 floating tap holder on your website!
I need to order another collet set and a floating tap holder if possible. What else have you got up your sleeve that I might include in my order?
Edster, I've done the same when I need 60% thread or less, gotta love threadlock Loctite!! [img]smile.gif[/img] I just wanted to make the point that rigid tapping with a flaoting holder is not rigid tapping. Programming rigid and using a floater is able to be done, but one should float on center on a lathe, UNLESS the application allows otherwise. How's that?
Maritool, the trouble comes when you have three holders in each machine, now what do you do with the other 200? Just seems to be the story of machining as far as I can tell. Too much or not enough of something or another.
Yes I have them. C1.0-TER32. It is 1.0 straight shank and takes ER32 collets. I am waiting for professional pics and I will put it on the website. I will P.M you. As far as other things up my sleeve, you name it. I can get much more than what my website shows. Just name it.
Yes Kustomizer that is always the case. Sometimes I feel like a full time purchasing agent instead of a shop owner. Sometimes in one day I have 10 different things coming in from 10 different locations. And its never enough.
NMTB 30 tooling.....collet holders, end mill holders.
I can get much more than what my website shows. Just name it.