Make a tool holder
by Dave Eaton

Many useful woodturning tools are only available in the form of a "bit" or "tip" rather than a fully handled tool. A couple that come to mind are the Wolok or Martel Hook Tools and standard Two Flute End Ball Mills which are used for end grain hollowing of open forms like boxes and vases. Additionally for closed form hollowing square carbide tool tips can be used such as David Ellsworth shows. One reason these are sold as bits form is they are made of extremely hard steel which prohibits them from being long in length.

Since these tool tips are usually not supplied with the supporting "holder" needed to use them for turning, one must either purchase a suitable holder for around $25 or craft one themselves.

The latter is the subject of this article. You need only rudimentary metal working skills and equipment to take a round steel rod and adapt it for such use. The cost of making such a tool is considerably lower than a purchased product and is nearly identical when complete. The holders made as shown cost about $7 each.
 

First, let's start by understanding the problem. The tool bit is typically a piece of metal with a special grind on it which terminates in a short one or two inch straight shaft for mounting such as the Wolok Hook Tool shown here. If the bit were not held firmly by the rod as shown it would be of little use. Once we have a steel rod holding the small bit we are then able to use the tool just as it is or, as is often done, with the other end of the rod inserted into a wooden tool handle such as would be typical of any other woodturning tool.

  


Hook Tool inserted into rod
 
Even though the rod is simply a length of steel with a hole drilled into the end it can be a little tricky to fabricate for the ordinary woodworker who lacks access to a metal working shop. Let's see how we can easily machine one of these rods using tools most woodworkers have access to.

First of course, you need to obtain a suitable length of useful diameter steel rod. Choose either cold rolled, mild, or galvanized steel rod as it is reasonably soft enough to machine easily. This material is readily available at home centers like Home Depot or Lowes, Ace hardware etc, or can be purchased from MSC Industrial Supply, Grainger, Enco Tools and more.

The diameter of the rod can be critical. It must be large enough to allow a hole size in the end to accommodate the bit you will insert and rigid enough to withstand bending or vibration when working at full depth. For hollowing to a depth of less than 18 inches, a 5/8 inch diameter is recommended. For deeper hollowing move up to 1+ inch diameter. If I recall correctly, Mitch Wolok, who developed a hook tool, said he can hollow perhaps 3 feet deep with a rod larger than 1 inch (and 6 ft long!) but for our discussion let's stick with 5/8" diameter rod which is probably all we'll ever need.

Most steel rod at local hardware stores will come in a 3 foot length. This is a bit long for our needs so cut it with a hacksaw to a shorter length. My choice is to cut it right in the middle yielding 2 each 18 inch lengths for 2 holders. You could choose 12 inch lengths but after burying 3 inches into a wood handle your maximum hollowing depth may not be sufficient.
 
Next comes the fun stuff. Place the rod vertically into a vise or clamp, mark the center with a marker or better yet scribe a couple intersecting lines with a nail, awl or X-acto knife. Use a center punch and punch the center for ease of starting the drilling.

Since there are rotational forces that will be working on the bit when in use, it is also a good idea to add a set screw or two to the side of the rod to prevent the bit from twisting. Some turners use superglue for this which seems to work fine, although it makes bit replacement more difficult.
 

  


End of rod center punched

An easy way to mark the side of the rod for the set screws is to simply run a file across the side with one pass while keeping the file held in a consistently "flat" angle. This will mark the steel with a small shiny flat which can then be used as a reference. Making sure the reference line is at the top, scribe marks for your screw hole locations.  The marks shown are at 1/4 inch and 7/8 inch from the rod end, but the locations are not critical as long as you assure that the screws will in fact make contact with the bit when inserted. Punch these locations for drilling as well.
 		  


Side of rod marked for set screws

Place the rod into a drill press, up through the center hole in the table and clamp it in place. If your rod wont fit or drill press table has no hole then you might alternatively tilt the table 90 degrees and clamp accordingly. I use a wood screw clamp with a "hole" in the jaws to grip the rod.  Drill a pilot hole in the rod with a spotting drill or other, preferably small and short drill that will not wander such as a 1/8 inch bit. A spotting drill is made specifically for this, to be strong and not wander from the center punched dimple. Be sure to apply sufficient cooling oil during drilling or smoke is all you will get. The 3-in-1 oil brand is suitable, even motor oil if you're desperate.
 		  


Spot drill the center to 1/8" deep

Once a pilot is drilled switch to the larger diameter drill bit which will accommodate your tool bit shaft and re-drill the same hole to desired depth. For the hook tool, since the bit shaft is 1/4 inch dia. I use a 5/16 inch drill bit which allows for shaft imperfections but is small enough for good support. The hole depth is about 1 inch. Don't worry if the hole isn't straight or exactly centered either. Do your best, but when you're using the tool to cut - the wood "will never know." This process can be done with a hand drill if due care is taken. The results will perhaps not be as precise but the end result will work fine.
 		  


Drill full size dia. for bit.

Remove the rod and re-clamp it horizontally for drilling the set screw holes. Again use a spot drill to prepare and then re-drill to a size appropriate for the set screw.

A #29 drill bit is needed for 8-32 x 3/16 inch set screws. 
 

 

 

  

 


Drill set screw holes
 
Once drilled, tap the holes with a hand tap, using oil again, and your almost done.

In fact the only tasks left are cleaning up and assembly.

To ensure that the rod will fit into a hole drilled into wood for a handle if desired, grind the back end of the rod slightly easing the sharp edge and removing any burrs.

 


Tapping the threads in the hole
 

Additionally, it usually a good idea to round the working end of the rod a bit to prevent a sharp edge from causing injury or scratching your work.

It's as easy as rotating the end of the rod against the grinding wheel, raising and lowering the far end until satisfied. If a nice shine is desired you may buff the steel or use sandpaper or Emory cloth to bring out the finish desired.


 

  


Chamfer the ends of the rod

Lastly, insert the tool bit and tighten the rear set screw assuring it grabs the bit. Then install any other set screws. You may need to file the heads of the set screws slightly to bring them down to the surface of the rod, but be sure to leave enough hex socket to remove them later. If they are too long, remove them and grind down the other end.

Congratulations - You're a machinist!

  


Finished rod with bit installed

You can use this rod to hold many styles of bits like these below:

  • Hook Tools for open form end grain hollowing
  • Ball End Mills for open form end grain hollowing
  • High Strength Cobalt steel tool bits for closed form hollowing (i.e. Ellsworth)
Sources:

M2 Hardened Wolok Hook tool bits - <$30
Andre Martel Hook tool bits - $40 to 90 per size
Ball End Mills - Enco or MSC - $15
Hard Tool Steel bits - $3
1/8" Spotting Drill - $3

These below are normal hardware store items:
5/8 Steel Rod - 36" lengths $12 at Lowes
8-32 x 3/16" Set Screws - 0.20c
8-32 Tap - $3
#29  High Speed Twist Drill bit - $3
5/16" High Speed Twist Drill bit - $5
3-in-1 oil or cutting & tapping fluids - $3

   Make your own hook tool by A. Lacer
Info on Hook Tool by Mitch Wolok


Finished rods and hook tools

Buy a hook tool here

+++
Jan 2007
(c) Dave Eaton 2007 - Rights of use or reproduction in whole or part freely allowed provided Dave Eaton cited as source.