Using drill press to tap

[Lone Watie]

I plan on building a tap guide from mini-lathe.com to use on my lathe, but until I do I'm looking for way to hold a tap vertically while tapping my threads.


I saw in Chapter 4 of the Army Manual 9-254 a picture of using a drill press chuck to hold a tap while turning the tap with the holder (non-powered, of course). My question is, how do you maintain the downward pressure with the drill press wheel while turning the tap with the holder?

 

[talkingmonkey]

Many taps have a recess in the end (or the tap holder) to accommodate a 60 degree center that will help guide the tap. There is even a spring loaded live center to free up your third hand.

Jeff

 

[Lone Watie]

Many taps have a recess in the end (or the tap holder) to accommodate a 60 degree center that will help guide the tap. There is even a spring loaded live center to free up your third hand.

Jeff

That's what I plan on building for my lathe - was just curious how to hold downward pressure on the die by using the drill press wheel. Do you have to lock the depth of the chuck to hold it in place, make a turn by hand, and then readjust the depth on the press?

 

[talkingmonkey]

I have been using a bungee cord to keep constant down pressure on the quill. Not very scientific but it works for me.

Jeff

 

[Tom Griffin]

It's a little scary the first time but you can do all of your tapping in the vertical mill or on a drill press if the work is clamped. Just set the machine to low RPM, put your tap in the chuck hand tight and power tap using the reversing switch to back it out. If the chuck is not too tight, the tap will slip when it bottoms out and not break. Always use plenty of cutting fluid and stick to the larger taps until you get the hang of it. And of course, be sure to wear safety glasses!

Tom

 

[george wilson]

Power tapping without a tapping head is a very risky proposition. You have to get the drill press chuck JUST tight enough to turn the tap,but loose enough to stop when it bottoms out??? I am a very experienced machinist,but I can't endorse this.

I have a simple little tapping head that has a clutch you can set,and when you pull up on the d.p. handle,it auto reverses and draws the tap out of the hole.

 

[pdentrem]

Put a lanyard on your hammer and hang the hammer off of the handle. A 10 pound hammer does pretty well for applying downward force to help tap your holes.

 

[Tom Griffin]

Power tapping without a tapping head is a very risky proposition. You have to get the drill press chuck JUST tight enough to turn the tap,but loose enough to stop when it bottoms out??? I am a very experienced machinist,but I can't endorse this.

I have a simple little tapping head that has a clutch you can set,and when you pull up on the d.p. handle,it auto reverses and draws the tap out of the hole.

It's actually not as risky as it sounds and it's pretty difficult to break a tap any larger than a #10 by hand tightening the chuck. Perhaps I should have specified this as an advanced technique; not for the neophyte machinist and not for the faint of heart.

A tapping head is definitely the best way to go if you have one. We always had a drill press set up with one just for tapping.

Tom

 

[Tom Griffin]

My hat is off to you Tom. The mill yes a drill press definately a no-no. As an experienced machinist (40+ years) I have never even seen this attempted. Not under power without a tapping head. Most drill presses don't have a reverse switch so if the tap galls you are up the proverbial creek. I cringe just thinking about it.

Back to the original question. Light pressure on the quill handle and use a "Tommy Bar" to rotate the chuck.

"Billy G

Good point Bill. I actually replaced my drill press with a mill so it's been a while since I've used one.

Tom

 

[Lone Watie]

Thanks for the great advice. What is a tommy bar? I like the hammer hanging off the quill idea (non-powered). Don't think I'll try it powered as mentioned, I don't have reverse on drill press. I might even have my tap guide made by then and this will all be moot. I just saw it in the army publication, and was curious.