No problem with my swivel head regular tool. The square head on my 2-56 tap is .106’'.
The tool’s collet has a 4 jaw chuck and is .140’’ ID in the relaxed position (not squeezed down/closed), this is the largest opening, flip the collet with four jaws around and it’s ready for a #80 drill bit, the smallest opening with four jaws. This swivel head pin vise came with two collets with both of their ends a different diameter hole, collet #1 largest hole .140’’ and smallest .034’‘, collet #2 is .046’’ and .084’'.
If I put my small files in a pin vise they would be awkward to use by being to long (file and pinvise OAL) and I would not have good control of the file. If need be, I screw a Blue #14-22 wire nut on the file’s handle end to protect the palm of my hand.
Another thought when taping threads in plastic like bolsters for trucks and for coupler screws. I think some would call these ‘‘Screw Bosses’’.
Maybe do not run the tap clean though the plastic hole, leave a little untapped plastic down in the bottom so the screw tip will bite into the untapped plastic and will keep the screw from loosening/backing out. Of course you have to measure the depth of the hole, and the length of the screw to make this work.
How to make a depth measureing tool.
Take a brass tube, .062’’ OD diam., .032’’ ID diam. x 1-5/8’’ long, now slide a very slightly bent (this bend will cause drag) brass rod .032’’ OD diam. x 2-3/8’’ long inside that tubeing, bent a 90* at one end of the rod and add a little eye on the end and thats it.
Put the TUBE on the face surface and push the ROD down in to the hole till it hits bottom, OR push the ROD down to the bottom of the hole and slide the TUBE down till it hits the face surface, remove and measure the ROD that is sticking out of the TUBE’s bottom. Thats how deep the hole is.
With a ‘‘blind hole’’, sometimes a ‘‘taper’’ tap will not cut threads down deep enough, then you go to a ‘‘Plug’’ tap, but if you need threads all the way down in a blind hole then you use a ‘‘Bottom’’ tap.
Please note, there are three different types of taps, Taper, Plug, and Bottom.
I would stongly recommend you buy a 2-56 set of all three. Most 2-56 taps sold for hobby use are plug taps.
The taper tap is perfect for through holes. The long tapered portion helps to align the tap with the drilled hole, and it is much easier to get a straight thread. Also, this style cuts the easiest and lasts the longest.
To cut threads in a non-through (blind) hole, start with the Plug Tap, then finish with the Bottom Tap, and you will get useable threading all the way to the bottom of the hole.
There are also two flute “Spiral” taps, but I have found these difficult to control. I have one in 2-56 size that has been useful when tapping in harder materials after starting with a Taper tap, but for most modeling I do not find the Spiral taps to be helpful.
To add a tiny note, I’d recommend that you sharpen the business end of the rod, so any scurf or taper at the bottom of the hole doesn’t throw the reading off, and then read distance on top of a mirror so you get a clear indication of length without parallax (you will notice that good meters feature this approach). You can rotate the rod slightly with the ‘L-bend’ lever at the top to ensure clean bottoming or to loosen any chips that have not been dislodged fully or cleaned out of the bore after tapping.
What he is talking about fabricating is a plunge type depth gauge. You would not take the reading directly from the gauge because it does not have graduations, you would measure the protruding rod with a ruler or caliper.
This is a similar method to reading telescoping bore gauges.
Parallax is not a factor when reading these measuring devices.
Everything that PC101 posted was good advice, useable, and correct as written. I use a different technique to get a slight interference fit for my truck screws, but it is just different, not better or worse.
Nope, no need to have a sharp point on the business end of the .032’’ ROD. With the ROD’s business end being flat I can ‘feel’ the bottom of the hole right up to the sides of the hole better then with a point on the end. I will ‘feel’ with my fingers and see with my eyes (well, one eye at this time anyway) if the hole has a taper (the center of the hole being the lowest and taper up to the sides) also ‘feel’ any chips. I also have a modified ‘Bore Light’ to light up the bottom of tiny holes.
As with rotating the ROD with the ‘L-bend’ at the top, nope again. It is much easier for me to rotate the TUBE and ROD together between my fingers to ‘feel’ the bottom and loosen any chips. I have never tried the mirror trick
I find the tap with a square section at the top of the shaft is better the section of the square shaft wont slip in the chuck. Taps without this feature really need to have the chuck tightened down with pliers and or a wrench so the don’t slip.
look at the photo in this link to see what I am talking about.
If you have any taps without the much liked square section at the top of the shaft heres what you can do.
I have a 1’’ belt sander and this is all eye ball mostly and a little micrometer/calliper work to check squareness. Take the tap and LIGHTLY sand the round shaft to a square at the end, keep dipping the end in water to cool it (I held the tap in my fingers to feel the warmth, warm is ok, hot is not, YOU DO NOT WANT HOT). With my little round shaft taps 00-90 0-80, I just sanded four flats (just remove a little of the roundness) on the upper 1/4’’ of the round shaft. No more round shaft spinning in the pin vise’s four jaw chuck.
If your pin vise only has three jaws, well then only sand three flats on the round shaft.
I prefer a pin vise with a swivel head. Remember to oil the hole to keep the tap from jamming and/or breaking. Work slowly, turning the tap forward and backward. The backward motion pulls the cut material out of the hole.
