Tapping machine idea

[lrsglory]

I am starting to build (thinking about starting) a pneumatic tapping machine. I saw one of these at a tool show about a year ago. Not sure it was this brand but it was similar. http://www.lans.com.tw/10-tapping_machine.html I have a heavy duty computer monitor arm that is as stable as the tapping machine arm I played with at the show. Not as much range of motion. I am thinking of using a reversible impact air screwdriver with a pressure regulator as the driver. http://www.harborfreight.com/reversible-air-screwdriver-90059.html It even looks like what they were using in the professional version. The guy wouldn't say but it felt like an impact wrench when it tapped holes. I would need to add a tap holder to the end but that looks easy enough.

So my question to the group does this look doable or am I missing some big problem? Has anyone on here built something like this and if so what were the problems?

As I see it I have to have a way to hold the tap, control torque, and keep it square to the work piece. Anything I am missing. This would just be for smallish taps ie 6-32 to 1/4-20.

Jeff

Larry Smith here: Lets skin another cat. I presume your wanting a tapping apparatus for power hand tapping off of your mill. If not lets start with your mill. A decent BP or clone will power tap on the table after the hole is in all day long. 1/2 -13 and have even done 5/8-11. Obviously use the mill while the piece is on the table and already lined up with the hole. put your tap in the collet or even a good true drill chuck. Low speed. Start feeding it in, after the start it feeds itself. hand on the reverse switch. When your there, reverse it and out it comes. No prob bob. be sure to keep the quill lock loose. This applies to taps no 10 and up. For the small stuff, depends on how brave you are, See the pic below. Collet, center, taphandle, tap. Bring the quill down, normal pressure. tap by hand. Keep light pressure on the quill to keep the tap and handle going in straight. Shazaam. When your there, hand back it out. Straight and true. Now for off the machine. See pic. I worked for an outfit for a year building automotive tube assembly machines. The frames were 3/8 thick, 3x3 soft steel. Tons of holes to drill and tap by hand to mount tooling. Might be building 20 machines. Hand tapping gets old. Ordered a butterfly 3/8 impact air tool. Wow. and cheap. Bought two generic tap handles. popped out the t bar, found a 3/8 drive socket to fit each one. welded them on, shazaam tap holder for impact tool. This butterfly worked great, fast reverse and air pressure regulator on the end. You could use a tapping block to keep it straight until your in. Season everything with your specs. tap size,depth, blind or thru. etc. Jusst spewing out some possible answers. Re: taps. Sprial Point tap ie gun taps are for thru holes as they push the spaghetti ahead of the tap. I preferred these even in blind holes. I would stop 3/4 thru in a blind hold and finish off of the machine after I cleaned the hole out. I agree with a previous post that Spiral Flute taps are weaker. They pull the chip out as they are tapping. Common to break a few of these if you use a real dull one. As always lots of oil, slow feed on the machine etc. Get a piece of scrap and try a few on the machine and offl. Before you assault the finished product.

 

[churchjw]

Thanks for the reply. My mill is a small bench top with no spindle break so no power tapping. But I like your description I will try in on one of the BP at work. I do use a tapping handle on the mill and that works great to get the taps started straight. I am very interested in the set up you have for the butterfly impact tool. I used one just like that to make my power drawbar for the mill and it works great. Why did you choose that over a power drill and how small a tap have you done with it? Again this is mostly to try building the tool not for any kind of production.

Jeff

Larry Smith here: Lets skin another cat. I presume your wanting a tapping apparatus for power hand tapping off of your mill. If not lets start with your mill. A decent BP or clone will power tap on the table after the hole is in all day long. 1/2 -13 and have even done 5/8-11. Obviously use the mill while the piece is on the table and already lined up with the hole. put your tap in the collet or even a good true drill chuck. Low speed. Start feeding it in, after the start it feeds itself. hand on the reverse switch. When your there, reverse it and out it comes. No prob bob. be sure to keep the quill lock loose. This applies to taps no 10 and up. For the small stuff, depends on how brave you are, See the pic below. Collet, center, taphandle, tap. Bring the quill down, normal pressure. tap by hand. Keep light pressure on the quill to keep the tap and handle going in straight. Shazaam. When your there, hand back it out. Straight and true. Now for off the machine. See pic. I worked for an outfit for a year building automotive tube assembly machines. The frames were 3/8 thick, 3x3 soft steel. Tons of holes to drill and tap by hand to mount tooling. Might be building 20 machines. Hand tapping gets old. Ordered a butterfly 3/8 impact air tool. Wow. and cheap. Bought two generic tap handles. popped out the t bar, found a 3/8 drive socket to fit each one. welded them on, shazaam tap holder for impact tool. This butterfly worked great, fast reverse and air pressure regulator on the end. You could use a tapping block to keep it straight until your in. Season everything with your specs. tap size,depth, blind or thru. etc. Jusst spewing out some possible answers. Re: taps. Sprial Point tap ie gun taps are for thru holes as they push the spaghetti ahead of the tap. I preferred these even in blind holes. I would stop 3/4 thru in a blind hold and finish off of the machine after I cleaned the hole out. I agree with a previous post that Spiral Flute taps are weaker. They pull the chip out as they are tapping. Common to break a few of these if you use a real dull one. As always lots of oil, slow feed on the machine etc. Get a piece of scrap and try a few on the machine and offl. Before you assault the finished product.

 

[awander]

An battery-operated "drill" with impact could be one of two things:

1) An impact drill(typically will have a chuck), made for drilling holes in concrete and the like. It will provide impacts parallel to the shaft, and would not be a good idea for tapping.

2) An impact driver(typically will not have a chuck), made for driving screws etc, using impacts, which will provide impacts tangential to the shaft. This is what you would want for tapping.

 

[lrsglory]

Thanks for the reply. My mill is a small bench top with no spindle break so no power tapping. But I like your description I will try in on one of the BP at work. I do use a tapping handle on the mill and that works great to get the taps started straight. I am very interested in the set up you have for the butterfly impact tool. I used one just like that to make my power drawbar for the mill and it works great. Why did you choose that over a power drill and how small a tap have you done with it? Again this is mostly to try building the tool not for any kind of production.

Jeff

I recall doing a bunch of 10-32, what a breeze. Never had to do anything smaller. If I did, I would probably figure a better way, since those small taps are easy to break or just try a few to see what happens. This of course was production tapping off the mill. Ya know, git er dun or else find another job. ! The occassional tapping would most likely be done by hand. you know a few. Our shop used air drills off the mill. When you did anything there was always a air hose within arms reach, never an extention cord. A good hand air drill will blow the socks off of any electric drill. man will they blow holes in and it doesn't take a lot of sweat. Re: tapping block. Just take a 1" thick 3 x3 piece of tool steel. Drill and ream some holes to match the tap dia. #6 to 1/2" heat treat and you got your guide for hand tapping. Hope this helps.