For all you machinist types...I need some help please!

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MesquiteMan

MesquiteMan

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I need a better method of tapping the holes in the lids of the stabilizing chambers I make. I start out with a piece of MDF and drill a 1 1/4" hole from the back side. This is then cast with Alumilite to make a "plug" for better threads. I am drilling a 7/16" hole with my drill press and then using a cordless drill to run the 1/4" NPT tap through. Each lid has 2 threaded holes in it doing all the threading by hand became too much, thus the cordless.

The problem is, it is real difficult to get the tap completely straight and sometimes the threads end up off kilter, making the gauge or other fittings not 90° to the top of the lid.

I have been looking at other options and have found the various machines for threading but they are way out of my budget. I have also seen some various different threading attachments for a drill press that automatically reverse when you begin raising up the bit. Do you have any experience with these? If so, can you give me any feedback on brands, etc? Also, what all do I need if I buy one of this type? I will not be able to buy a new one since the ones I have seen are all $400++ but there are a number of various different ones on E-bay that would fit the budget.

If this is not a good way to go or if you have a better suggestion, please let me know. Thank you in advance for any help you can provide.
 
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Could you not cast a brass female 1/4 pipe fitting in the alumalite when you make the plug?

edit in" Or a 1/2 to 1/4 or 3/8 to 1/4 brass reducer? It would have threads on the ouside to grab the alumalite.
 
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I have used the drill press for tapping metal to keep the hole straight, I am sure it would work OK for this all so.

Lin.
 
Get yourself a small block of steel about 1" thick. You want it big enough to hold onto or to clamp. I use one that is 2" x 4" x 1". Drill a clearance hole for each size tap you use using your drill press to insure you drill perpendicular to the block. When its time to tap, put the block of steel over the hole to be tapped. Line up the clearance hole with the hole to be tapped. Stick the tap through the clearance hole. If you drilled the hole perpedicular to the steel block the tap will be at 90 degrees. It will stay at 90 degrees while tapping.

I just hold onto the steel with my hand and it's no problem. But if you have trouble keeping the block aligned (or need two hands to tap), you can clamp it to the workpiece (or use double sided tape).

This is the way I was taught to do it in a machine shop 35 years ago. Sometimes simple is good enough if you don't have the capital to buy real production equipment.

Ed
 
Since you're doing it on the drill press, just take the drill bit out without moving the work piece, insert the tap in its place. use very light down pressure on the drill press handle and turn the chuck by hand to get the tap started. Without withdrawing the tap or raising the quill, loosen the drill chuck and raise it then turn the tap the rest of the way with a tap wrench since the tap is already started and perfectly aligned with the drilled hole.

If you have a tap wrench with a small hole in the top (some have them and some don't) just put a point in the drill chuck and use the point in the tap wrench hole to align the tap (and tap wrench) with the drilled hole and tap it by turning the tap wrench instead of the drill chuck (same operation as above but takes the hassle of chucking the tap and then releasing it out of the process). The make a spring loaded point tool for the chuck for this, but just making a point and using it by keeping slight pressure on the tap wrench by hand till it fully starts costs nothing and means one less tool you need that you may use only rarely)

Expensive hand tapping tools and such really only make sense if you either do a whole lot of repetitive tapping or just have lots of money and like lots of toys.
 
Mesquite Man,

If you go to the Australian Woodwork Forum under Wood Turning--Pen Forum 20th February a posting by Big Shed also a valued member on this site explains with pics his methods of threading for kitless pens, his tools he made and adapted to cheap commercial pieces to cut external and internal threads such as your enquiry. These enable the simple changeover using the metal lathe (also wood lathe) that may enable you to succeed in your case using these principles.

Have success Peter.
 
Back again this same info from Fred posted on the IAP 20th February this year under Advanced Pen Making New Tap Wrench.

This same device would work perfectly on your drill press as well. This assuming the press is set at right angles to the table in all directions. All in all a cheap efficient method IMHO.

I have a similar device now modifying it to do tapping as well, simply said it is a sliding device on a stem held in a tail stock or drill press utilizing button dies and a ratchet tap holder nested into the opposite end of the hand operated unit.

Trust this may solve your dillemma.

Kind regards Peter.
 
Guys, thanks for the ideas so far but I think I may not have made my problems clear.

Here is the deal, I am tapping 2 holes per chamber lid and typically do 12-15 lids at a time. That is 24-30 tapped holes. Add to this the fact that it is a large tap in 3/4" of Alumilite and you have a real chore on your hands doing it in any manual way. Trying to turn that big of a tap is a chore, even when drilled with the correct size bit.

Also, I need something that is efficient. This is how I make my living now and it is really not efficient to start the tap with the drill press, remove the tap, then finish with something else.

As for the steel block idea..the shank on my tap is not long enough to much of a thickness to act as a guide. I already thought of this and tried it, albeit with wood instead of steel but again, all I would be able to do is get the tap started somewhat, then back it out, remove the piece of wood or steel, and run the tap in again. Not something I really want to have to do on 24-30 holes!

As for casting in a fitting or using some type of bulkhead, the biggest issue here is cost. I try to keep the cost of my product as low as possible and really don't want to have to add additional parts that I have to buy and stock. Also, what typically happens is I drill the hole in the MDF, then cast it with resin. then I adhere a piece of plastic laminate to the bottom of the lid to seal the MDF and make it air tight. Then, I install the trim around the outside and adhere another piece of plastic laminate on the top to make more durable and to cover up the MDF. Getting a hole through that top piece of laminate to line up with the insert below would be difficult at best.
 
I am really looking for input on something like this: Dayton 2XUW2 Tapping Head 6JT 150 RPM 5/16-3/4 Cap | eBay

Have you every used anything like this and would it do what I need it to do? I don't mind spending this kind of money, I just can't spend big bucks for a dedicated threading machine.

Also, a question on this item...it says the mount is a 3jt. I assume this means a #3 jacobs taper? If so, my Rigid drill press uses a #3 Jacobs taper for the chuck. Does that mean that I can remove the chuck and install this on my drill press for use?

Thoughts?
 
Curtis,
That should do the job very nicely, I have had plenty of experience with this type of tapping head having had a manufacturing business tapping 500-800 1/4" dia at a time. I had 3 drill presses lined up, drill deburr tap.
The tapping head is also supplied with a #2 morse taper adaptor, its just a matter of drilling all your holes then removing the chuck and replacing it with the tapping head.
The price sounds reasonable.
Kryn
 
Sounds like you have the answer already, gonna have to spend some dough on tapping unit, eBay should be able to offer one for decent money or you could buy from one of the mill supply houses just check their return policy in case it doesn't suit your needs. I make custom spray manifolds in pvc & hand tap everything BUT my material is much more forgiving when tapping hundreds of holes & I use a 10-32 tap. I do sell bulkhead fittings really inexpensive but the smallest npt thread I have is 1/2" send me a pm if you picture- pricing. Iuse them in my Hydroponic business for reservoir drain.

Bill
 
Curtis:

This is what I use to make sure the tap goes in straight.
You drill the hole, remove the drill from the chuck put this in and put spring loaded center in the center hole of the tap, then tap your hole.

Works great for tapping one or two or six holes but if you need to tap hundreds then a tapping head would be best.
Enco - Guaranteed Lowest Prices on Machinery, Tools and Shop Supplies
9526747-11.jpg
 
Curtis, If you can find a Tapmatic, it would solve the problems, It would be best if you can slow your drill press way down, and still have enough power to drive the taps,$300.00 to $450 or so is retail, and they will do the job, but you might look on Craigs list, or feeBay and find one cheaper, I haven't seen any but there must be a Chinese Tool Importer that have them much cheaper though.



Guess I should have read on to the end of the thread!!
Curtis, that looks as good as the Tapmatic, and 1/2 the price!!​
 
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Curtis:

Why can't you make a threaded plug, and cast the resin around it under preasure to force the resin into the threads of the plug, then when cured un screw the plug?

No tapping required. :rolleyes: Just trying to think out of the box.:wink:

I agree with tapmatic brand, thats mostly what we used when I was doing the tool and die thing.
 
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rherrell said:
Curtis, the "mount" is a JT3 or Jacobs taper 3, that's the mounting taper for the hole in the tapping head, the other end has the Morse taper for your drill press.

I believe this is what you need...
Enco - Guaranteed Lowest Prices on Machinery, Tools and Shop Supplies
Click to expand...

Rick,

The link you gave takes me to a JT3 to MT3 adapter. My Rigid drill press has a JT3 chuck. Wouldn't I want a JT3 to JT3 adapter? All of this kind of stuff is foreign to me so sorry for the stupid questions!
 
OK, here is my latest idea that would be fairly cost effective...

Use a Hand tapping machine like suggested by Low 48 above but instead of installing the handle, make an adapter to connect my cordless drill. Remember, I am looking for speed and efficiency. Sure, I could just turn it by hand but a cordless drill will be much faster.

Here is what one looks like in case you are not familiar with them.
g8748.jpg


Thoughts?

Oh, btw, I tried drilling the hole with the drill press and then inserting the tap in the press and getting it started, then removing it and finishing the hole. That would work great for a few holes but with as many as I need to do on a regular basis, this is way too cumbersome and inefficient.

As for the one I posted a link to above that mounts in the drill press...I tried removing my chuck on my press and can not get it out. 15 years of it being in there has got it good and fixed in place! I am sure I could keep at it and finally get it out but I can see a real pain in the butt having to switch the 2 out regularly since I do use my press for many other operations.
 
Thanks, Bruce! i went ahead and pulled the trigger on the Dayton on E-bay here: Dayton 2XUW2 Tapping Head 6JT 150 RPM 5/16-3/4 Cap | eBay

Can not justify the cost of a tapmatic but this one, at $160 was palatable. The best I have seen this one on Grainger or DrillSpot is right at $500 so the $160 is a pretty good deal.

While on this subject, can you give me any info on what is meant by rubber flex collets? Both the one I bought and the TapMatics have this type of collect according to the web.
 
Oh yeah, I remembered today that I have an old, 1950's Atlas 1020 15" cast iron bench top drill press tucked away in storage that I have not been using that still works. I am going to try to use it as a dedicated tapping machine with the head I ordered.
 
MesquiteMan said:
rherrell said:
Curtis, the "mount" is a JT3 or Jacobs taper 3, that's the mounting taper for the hole in the tapping head, the other end has the Morse taper for your drill press.

I believe this is what you need...
Enco - Guaranteed Lowest Prices on Machinery, Tools and Shop Supplies
Click to expand...

Rick,

The link you gave takes me to a JT3 to MT3 adapter. My Rigid drill press has a JT3 chuck. Wouldn't I want a JT3 to JT3 adapter? All of this kind of stuff is foreign to me so sorry for the stupid questions!
Click to expand...


Curtis,

I don't recommend changing out the chuck every time, you'll need a special wedge for that, it's ALOT easier to buy an extra arbor to fit your new tapping head and change out the whole thing.
Lower the quill on your drill press all the way and there SHOULD be a slot. Do you still have that funny looking wedge thingy that came with your drill press? If so, stick it in the slot and whack it with a hammer, the chuck should drop right out with the arbor attached.

I just ASSumed your drill press had a MT3 quill , that's why I gave you that link, check your owners manual to find out for sure. No matter what Morse taper it is you can find it at Enco.

Your tapping head has a JT3 mount so figure out what Morse taper your quill is and get a JT3 to MT(fill in the blank) arbor.
 
(Your tapping head has a JT3 mount so figure out what Morse taper your quill is and get a JT3 to MT(fill in the blank) arbor.)
The Tapping head is supplied with an adaptor to fit the M2, most if not all decent drill presses are fitted with a M2 taper.
Kryn
 
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