The knurled sliding sleeve is gripped and pushed on the 1/4" turned part to be threaded (chamfered of course for easy starting). As the thread starts, the sliding sleeve is pushed toward the headstock. When at the appropriate thread length is reached the knurled sleeve grip is released and the sleeve and die turn with the rotating spindle. When hand holding you can let the die come right up to the shoulder and it will start turning with the workpiece as the knurled handle is turned in your hand. Stop and reverse the spindle and the die and sleeve will back off the work piece as you grip the knurled sleeve.
Again, liberally use cutting oil or cutting fluid.
Here are the five (5) drawings of all the parts. (Under revision)
#1 - Tailstock Arbor #2 MT
#2 - Knurled Sleeve
#3 - Thread Die Holder 13/16" dia. & 1" dia.
#4 - Jacobs Collet Tap Chuck Adapter
#5 - Stop Handle
#6 - Hand Tapper Collet Holder
Here are the 8 pieces that make up my everyday Tailstock Tap/Die Holder set, including the wrench for the nut on the Jacobs Collet Tap Chuck. I also have the larger Jacobs Collet Tap Chuck with 1/2" tap capacity.
Here is a #6 tap held in the Hand tapper Collet ready to be inserted in the collet holder for the Tailstock tool. The collet has a square that grips the tap and a set scres to lock aganist the shank of the tap. The 2 set screws in the holder are snuged aganist the flats on the end of the Hand Tapper Collet.
In this photo below the tap has just started and as the material is aluminum
I'm able to hand hold this 1/4-20 tap.
This photo below shows the stop handle flipped to the back side when the spindle
is reversed for backing the tap out.
Here (above) I'm tightening the Collet Chuck hardened back jaws on the tap square. This is one of the unique features of the Jacobs Collet Chuck, allowing for different size squares. One back jaw is RH thread and the other LH so adjustment with an allen hex wrench is from only one side. Quick and easy. The shank of the tap is then gripped by the adjustable rubberflex collet at the front of Collet Chuck and then snuged with the wrench provided. The flat on the tap is shown thru the round side hole.
Tailstock Tap/Die Holder (Original using Jacobs Collet Tap Chuck)
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I made this tailstock tap/die holder for my 9” South Bend lathe. I’ve used it often and received many compliments. I made and sold a few using the Jacobs Tap Chuck as shown in these photos. Unfortunately the used Jacobs Collet Tap Chucks got almost impossible to obtain on eBay (and if you did find, usually very expensive) so I redesigned the tool. In place of the Jacobs Tap Chuck I now make the standard 7 piece tool using two altered T-handled tap wrenches for holding the taps. One with 0 - 1/4" tap capacity and one with 1/4" - 1/2" tap capacity.
In addition, due to customer requests, I now offer a 1/2" to 3/4" tap capacity tap holder and a 1-1/2" extended die holder as optional purchases. These larger sizes have exceeded the capability of the tool but a number of customers use the tool for much lighter materials, plastics, molded materials, aluminum, and even wood. These materials frequently necessitated larger tooling but easily did not exceed the strength capacity of the tool. So i now offer these larger holders as an option.
Getting back to this tool shown here, my original tailstock tap/die holder with the Jacobs Rubber-Flex Collet. As writer and author Frank McLean (Village Press, Home Shop Machinists Magazine, etc.) says, “A tailstock tap/die holder should be among the first accessories an amateur makes for his lathe, since threading and tapping with hand-held tools is seldom satisfactory.”
McLean’s tool was just a tailstock die holder. By utilizing the Jacobs Collet Tap Chuck or the modified Tap Wrench Holder I was able to easily make the tool for both tapping and threading, adding greatly to its usefulness.
This tool is especially nice to use for small taps, #0 to #10 for example. It can be hand held for these smaller taps and dies. Taps and dies 1/4" and sometimes #10 usually require use of the stop handle as there is too much torque to hand hold. Either application provides for a quick accurate method to produce threads.
The unique feature of this tool is the Jacobs Rubberflex Collet Tap Chuck for holding and gripping the tap. This chuck utilizes one collet that takes all taps in its range without requiring individual sleeves. The chuck has hardened steel jaws to grip the taps square drive. A tap cannot be held in a standard drill chuck it must be held in some type of holder that grips the square of the tap.
Specifications: (For this Jacobs Tap Chuck version)
Tap Capacity #0 to ¼”
Die Capacity #0 to 5/16” with 13/16" die holder and #0 to 1/2" with 1" die holder
Die Holder Capacity 13/16” or 1" Diameter Dies Tail stock Mounting #1 Morse Taper and #2 Morse Taper
Knurled Sleeve 4-5/16” lg. 5/8" bore
#2 Morse Taper Arbor 6-1/2” lg.
3/8” Diameter Stop Handle 5-3/4" lg.The Jacobs Rubberflex collet has a capacity of 0.139” to 0.257.” All taps #6 and under have a shank diameter of 0.140”. A ¼” tap has a shank diameter of 0.255”. So all small taps can be used, it is just up to you how small you want to go. Jacobs has a rubberflex collet available for this chuck that will accept the 0.317 shank diameter of a 5/16” tap.
Complete 7 Pc. Set (See 1st Photo below)
Jacobs Collet Tap Chuck (#0 to 1/4" tap capacity)
Knurled Sleeve (4-5/16” lg. 5/8" bore))
#1 Morse Taper Arbor (6-1/8" lg.)
#1 to #2 Morse Taper adapter
Stop Handle (3/8" dia. x 5-3/4" lg.)
Die Holder (13/16" dia. capacity)
Wrench 1" for Jacobs Chuck Nut
Above, thread die retracted prior to completion of the threading.
Operational Photos - Tapping
This photo below shows the tool set up for hand held tapping. I run the lathe in the lowest back-gear speed available. On my 9" South Bend that is about 50 RPM. I run at this speed for both tapping and threading with a die. By gripping the knurled sleeve you slide the knurl toward the workpiece forcing the tap into the tap drilled hole (chamfered edge of course). When the tap thread engages the work the turning workpiece pulls the tap into the hole, if you release your grip on the sliding sleeve it will rotate with the workpiece and stop cutting. Gripping it again will start the thread cutting again.
When you are a the correct depth stop the lathe and release your grip at the same time. This is easily done at this slow spindle RPM. Reverse the spindle rotation, grip the knurled sliding sleeve and the tap will back out.
Use cutting oil or cutting fluid liberally
Hand holding is very precise, especially when using the smaller taps and dies. I've had great success both tapping and thread cutting #0-80 in aluminum. With care I'm sure steel would be no problem.
Close-up of 2 of the collets.
At the very end following the drawings is a photo of my everyday 8 piece set with a #2 MT adapter.
This is the Hand Tapper I spoke of earlier. Note the wooden rack for holding the 9 collets and note the 3 collets on the machine table. They call them collets but thy're just a round holder with the appropriate bore for the shank of the tap. The wooden rack has holes for 12 collets
One of the collets is inserted in the Hand Tapper Collet Holder.
Above are 6 of the 7 pieces of the original tool, missing is the 13/16" die holder
This photo below shows the Jacobs rubberflex collet and the nut. Also, the hardened back jaws can be partially seen. The back jaws are loose in the chuck body providing for centering on the taps square. An allen hex wrench then clamps the back jaws against the tap square.
Operational Photos - Threading, using round adjusstable split die
This photo below shows the tool set up for threading using a 1/4"-20 die. The operation is much like the tapping oeration
Ready to be inserted into the knurled sleeve. Tap, collet, collet holder and knurled sleeve.
Home Shop Machinist
This above photo shows the 3/8" dia. stop handle installed. For #10 threads and below the knurled sleeve can usually be hand held. For 1/4" and #10 in steel the stop handle is usually necessary.
The photo below shows the Jacobs Rubberflex collet tap chuck holding a 1/4-20 tap and a 1/4-20 adjustable 13/16" round die in the die holder. The die holder and the Jacobs collet chuck are interchangeable in the knurled sliding sleeve.
The knurled sleeve holds either the Jacobs Tab Chuck or the 13/16" round die holder (or 1" round die holder) with a set screw aganist a flat.
The knurled sleeve slides on the 5/8" dia. shank of the #1 morse taper arbor. A #1 to #2 morse taper adapter is provided for fitting to most small to medium size home shop lathes.
For 1/4" taps and #10 in steel I usually use the 3/8" stop handle shown below. The photo shows the stop handle in use. I start the tap as described above and let the stop handle hit against the carriage. Depending on tap depth required (make sure your drilled hole is deeper than your tapping depth) I usually tap a hole in a series of steps, stopping and backing out and then starting again, liberally applying cutting oil or fluid. One can be very precise when hand holding because of the low spindle speed and by being able to immediately stop the tap by releasing ones grip.
Above, the stop handle installed while threading with 1/4" adjustable die
In use, #6 tap ready to thread a brass workpiece, hand held. Works as well as the Jacobs Collet Tap Chuck but not quite as speedy.