Help designing a Tapping fixture

[RJSakowski]

I came across this awhile back but do not remember who to give the credit to. I saw a pic and copied it. View attachment 265769View attachment 265770View attachment 265771
It uses an Irwin tap holder for a 3/8” square drive. The tap holder is a very good piece. I used a piece of 1/4” drill rod for the stem and handle, and the body is 12L.
The hole in the body for the stem is tight enough that it holds a suction. Just chuck up the stem and the body just slides onto the stem. Works great.

I believe that was my post. I made mine with a 3/4" diameter to fit my TTS adapter. I also have a 3/4" chuck with an MT3 shank for my lathe so I can use it there as well.

 

[Z2V]

I believe that was my post. I made mine with a 3/4" diameter to fit my TTS adapter. I also have a 3/4" chuck with an MT3 shank for my lathe so I can use it there as well.

RJ, let me take this opportunity to say thank you. I hope you don’t mind me making one for myself.

 

[machinejack]

Yep start the tap in the chuck. My chucks key handle is the same size as the pilot holes on the chuck insert it and you have a tap handle.

 

[MrWhoopee]

I have a pair of tap handles with a free turning dowel pin in the end opposite the chuck. The dowel is held in the drill chuck, the handle turns freely and moves up and down while tapping. Here's one

https://uedata.amazon.com/Walton-70276-Piloted-Spindle-Tapper/dp/B0006N8DWS

Back in the day, we routinely power tapped in the mill just using the drill chuck. Fred nearly freaked when he saw me tapping 1/4-20 at 1200 rpm and throwing the mill in reverse when it got close to the bottom. Made good time though.

I'm less bold now that I don't have a pack of every size tap in the drawer.

 

[Glenn Brooks]

something must have gone over my head as i don't see why you just don't chuck up the tap in a drill chuck and go to work.

Common guys, this is way to simple. Machining is supposed to be hard and complicated!

Great comments!

Actually I did tap the first hole in the drill press with a small, shop made dead center held into chuck. But it came out ‘crooked’- out of vertical, so started nkimg a better fixture to control the tap.

The workpiece here was a large T nut, that holds my new QCTP onto the compound slide of the lathe. My first tapped hole, using the DP and the dead center, threw the tool post shaft out of vertical enuf to prevent the toolpost from seating flush with compound. Not good! So fairly gun shy going into my backup second hole position. At the time, I assessed I didn’t have enuf constant downward pressure to guide the tap consistently. So the tap wobbled to much and the hole came to far out of vertical and I couldn’t use it.

Also I realized from your post, I should have held the top of tap rigidly, as in a drill chuck. Looks like this is the primarly selling point of most of the commercial tap guides mentioned here.

Second time around, I drilled the work piece when mounted and centered in my mill. So did not want to loose this vertical alignment control by taking it out and using the drill press.

So now thinking it would be good to have a fixture that I can use routinely on the mill, (or DP) that provides this downward pressure, and holds the tap rigidly at 90*, and, somehow slips and into place without loosing center. I like the tap followers that Francist and Z2B show. These seem to meet all the criteria.

Also, I do want to go out in the shop and practice some power feeding with the drill chuck, as described below. See how well it works. This would be very interesting to learn how to do.

Glenn

 

[cg285]

i thought everyone did it this way.

 

[RJSakowski]

Glen, Here is the post that I made regarding the tap guide. https://www.hobby-machinist.com/threads/super-size-tap-guide.41691/

In my experience, it isn't necessary that the tap be rigidly held. My method for tapping a hole is to drill the tap diameter hole in a clamped workpiece, load the tap follower,and the tap in the tap wrench or chuck. That way, the tap is in line with the drilled hole and will tap true to the hole. The tap follower provides downward pressure to keep engaged with the tap wrench.

An added benefit is that the possibility of breaking a tap is greatly reduced. Two of the biggest reasons for breaking a tap are not tapping true to the hole and applying side force to the tap while tapping, both of which are eliminated.

A drill chuck can be used but one hand is required to apply the downward pressure which leaves just one hand for turning the tap and applyibng tapping fluid. It works better on a lathe where you can leave the tailstock free to slide. Power tapping works with a drill press and the right taps. With hand taps, chip clearance can be a problem as it isn't convenient to reverse the tap after a half turn or so.

 

[stioc]

I just got done tapping a bunch of holes in a fixture plate (more pics and details in my RF30 build thread) using a Brown and Sharpe tap guide/follower, $20 on Amazon.

 

[Groundhog]

I went to tap a hole with a new Fastenal 3/8-16 tap on the drill press so I out dug my tap follower, clamped it in the chuck and went to stick the end in the tap's little hole. No fricking little hole, no little pointie end either. Just a flat surface. Fastenal found another way to cut costs and screw the end user at the same time.

 

[stioc]

Funny you mention that because out of 5 or 6 tap holders including a couple of very old USA made ones the only one I had with the hole on it was from my cheap Harbor Freight tap/die set.
Otherwise I was going to put a center hole in one on my lathe. BTW, the HF tap/die set has worked well for me for about a yr now. I'd love to get a quality HSS tap/die set some day though, just can't stomach the $400+ for one right now.