Tapping 1/2-13

[GlennW]

I usually tap in back gear on the Bridgeport and plug reverse using a slight up pressure on the quill feed when backing out. My quill spring is set neutral so it does not retract on it's own, so I have better feel on the quill handle for small drills and taps with it set that way. You will have to get the feel for it, as in softer metals the first thread can get slightly damaged when the tap/quill retracts.

I'm not sure you can plug reverse with a VFD, but a hand on the brake lever to stop at the correect depth may work if needed to get your timing down. Hit the switch and pull the brake if it wants to coast in farther than you want.

There is no law that states you can't stop a smidge early, disengage the spindle drive, and give it a final turn or two by hand if depth is critical!

The VFD may not like that either though!

Masking tape around the tap covering the threads you don't need for blind tapping works as a good visual aid for proper depth. Works good for multiple holes anyway.

Oy yea, and there is nothing like new, sharp, top quality taps and lots of good tapping fluid! (cheaper in the long run anyway)

...and like reamers, don't let them rattle around in the drawer together.

[EdK]

I've seen the term "plug reverse" used in this thread a couple of times now. What is "plug reverse"?

Thanks,
Ed

[GlennW]

Switching from foreword to reverse instantly.

On a 3Ø motor not controlled by a VFD, it instantly reverses.

On a common 1Ø motor, it keeps going the same direction.

There are however, from what understand, some specialty 1Ø motors available that instantly reverse.

[GlennW]

Works great in the lathe as well.

Here is the lathe version of tapping 1/2-13 since PixMan will have the mill version covered shortly.

Click on it.



The tailstock needs to be snugged down, but only to where it still slides ferrly on the ways, which are oiled, of course. This primarily applies to smaller machines with lighter weigh tailstocks as the torque from tapping willl rock the tailstock and cause a bit of heartburn.

Start the spindle, push the tap in to start it and the helix will draw it in

Stop where you want it.

Reverse, and the helix will push it back out. Slight pull on the tailstock is needed when the tap pushes out so the tap clears the bore without fouling the first thread.

Just remember to plan ahead if using a single phase machine, as it won't reverse before the spindle stops!!

I guess you could view it sideways....

[EdK]

Switching from foreword to reverse instantly.

Glenn,

That's kind of what I thought it meant but did not want to assume since we all know what that does.
Thanks for the lathe tapping video, it helps.

Ed

[Richard_W]

Removing the chip afterwards can be tricky, but a needle tip with an air hose makes short work of the task.

A selection of knitting needles are great for picking chips. Very cheap, and color coded too.

Dave J.

I keep several styles of dental picks to remove chips in blind threaded holes. They have a bend in them so if you insert the pick while turning it, it grabs the chip and you can pull them out. Sometimes they all come out at once. The other advantage is the small size of pick can go into some really small holes.

Richard W.

[millman5]

I use spiral point taps everywhere I possibly can, even in blind holes unless there is just no extra drilling depth.

If I compact the chips I have found a left hand drill chucked in a cordless drill will grab the chip ball and thread them right out of the hole. Follow with air.

Harold you are spot on on needing "feel" on the quill. I keep my return spring backed off as far as I possibly can. In fact just enough to lift a common 1/2" drill chuck. I find myself having to help boring heads etc. back to stop.

My BP clone doesn't sound as if in much likes to be instantly reversed. I usually just kill the power & grab the brake then reverse. Lots of things I tap on the mill there is enough inerta in the machine if it is running in the back gear, to kill the power then enter the hole & coast through. This works exceptionally well with a VS head & tapping pipe threads. All you have to do is get the speed right on a couple test pieces. Not worth it for a 1 off but works great for production.

[PixMan]

Works great in the lathe as well.

Here is the lathe version of tapping 1/2-13 since PixMan will have the mill version covered shortly.

Couldn't get it done today, sorry. I had to take my dad to the hospital last night, he's come down with a form of pneumonia. While I did get some work done at the shop and have the workpiece ready for the tapping video, I did have to stop and go visit my dad. (He's doing OK, probably coming home on Monday but may have to use oxygen from here on out.)

[GlennW]

Couldn't get it done today, sorry. I had to take my dad to the hospital last night, he's come down with a form of pneumonia. While I did get some work done at the shop and have the workpiece ready for the tapping video, I did have to stop and go visit my dad. (He's doing OK, probably coming home on Monday but may have to use oxygen from here on out.)

Oh, man, I'm sorry to hear of your dad's health issue.

But it's good to hear he is recovering and will be back home soon!

[wsippola]

While you're ordering your 1/2" gun tap, order two each of the common smaller sizes. They're pretty cheap (although it's been a few years since I've bought any), and once you start using them, you won't use anything else unless you have to. The ones I bought were listed as the better import (MSC??) and I have yet to break one.

I also have a couple tapping heads. I don't think it was more than $30 for the pair (ebay). The larger will easily do 1/2 inch taps and the other is nice for smaller stuff. Just a matter of popping out the drill chuck on the drill press and putting in the tapping head. If I have 3 holes to tap, I will use the tapping head. For two, I might depending on size. If you do much tapping, keep an eye out for one - the procunier go rather high, but you will find cheaper ones can be had.

Happy New Years,

Wayne

[EdK]

PixMan,

Don't worry about it. Your family is much more important. I wish him a speedy recovery.

I have to get the proper tap yet anyway so I worked on some other aspects of the project today. I'll place the order for the tap this evening and I should have it by Wednesday.

Ed

[EdK]

While you're ordering your 1/2" gun tap, order two each of the common smaller sizes.
Happy New Years,

Wayne

Wayne,

I already have most of the smaller size taps in spiral point, plug and bottoming taps. I just don't happen to have the 1/2-13 in a spiral point. I thought I did otherwise I would have ordered one prior to starting this project. I guess the memory is starting to go with advancing age.

And a Happy New Years to you

Ed