Build - Thumb Plane

Preparing the Body Core and Sides

The starting material for the core is 1018 mild steel, 1" x 1" x 2.6". This is first milled on two sides to a thickness of 0.770" by first rough milling with an end mill, and then finishing with a fly cutter.

Next, the core is sandwiched with the two brass sides and one end of the combined sandwich is milled flat (see pictures below). After milling the first end, the cut end is carefully de-burred while the sandwich is held in the vise. The sandwich is then carefully reversed (so as not to shift the side plates), and the other end is also milled flat (again - de-burr before removing from the vise). Tip: Cutting lubricant on the sandwich will act to weakly "glue" the sandwich together.

Important: Do NOT mill the sandwich to final length at this point; we want to leave it a bit long for now, so we can mill to final length later.

In the next step, the top and bottom are milled flat. Again, the minimum amount of material should be removed, so as to leave the piece oversized. In order to raise the piece high enough in the vise, parallels are stacked sideways (only because I had thin parallels and I did not want to risk having the core slide out of place). I measured the thickness of the parallels, and found a very minor taper in the thickness ranging from 0.001" to 0.002" - by carefully reversing one or two of the parallels so as to cancel out the taper, I was able to reduce the difference in the stack to about 0.001" which is accurate enough for this application.

With the sandwich clamped "sideways" in the vise (see pictures below), the top is milled flat, and then carefully de-burred. The piece is then flipped over and the bottom side is also milled flat. The primary body pieces are now ready for drilling.

Drilling and Tapping the Body

The body sandwich is now placed in the vise with one brass side up. An aluminum shim is used on one side of the vise to ensure that the brass plate is clamped firmly and does not slide over the steel core. After starting drilling, I found the top plate starting to lift, so I added an addition shim of index card positioned behind the edge of the brass plate only - this did the trick and I experienced no further problems. [see photos below]

The 0,0 position of the piece is then set as follows: The left side of the piece is set to zero, shifted left 0.010" and then reset to zero. The forward-most edge is similarly set to zero, moved forward 0.010" and reset to zero. To put this another way, the X,Y coordinates are offset by 0.010" in both the X and Y positions. All holes will be drilled with their coordinates based on this offset; this allows 0.010" to be milled from the left end and bottom after the screw holes are drilled and tapped, so as to correct for any minor misalignment which might occur during the drilling and tapping operations. All of the drilling operations are based on X,Y coordinates supplied on the plans.

Following drilling, all holes were tapped with a #4-40 plug tap. I started the tap using the drill chuck to ensure alignment (turned by hand); once the tap was started I switched to a tap handle. The tap handle I used was a bit large (but is the smallest one I have), so care was need to make sure I did not snap a tap. After tapping all screw holes, all holes were countersunk. I inserted a screw into each hole as it was completed (blowing it clean with compressed air first). [see photos below]

Preparing the Core for the Handle and Axle

The sides are removed from the core, and the core is center drilled to locate the axle hole. The hole is then drilled with a succession of ever larger drills to almost the final size. The final diameter is obtained by boring the hole, to ensure a smooth round hole. The operation is completed by chamfering both ends of the hole (not shown). See photos below.

A slot is milled for the handle screw using a 0.250" end mill. The slot is initially cut undersize, and then carefully enlarged to intersect the axle hole. The completed slot is tested with the handle and axle before removing from the mill vise.

Handle and Axle

The axle is simply a bit of brass rod, turned for a smooth fit in the axle hole, and cut to length. The completed axle blank is then drilled and tapped for the handle screw. See photos below.

The handle blank is turned to shape on one side and tapped. The blank is then reversed by inserting the handle screw in the blank, and then screwing it into a short piece of internally threaded rod (mandrel) prepared for this purpose. To achieve the gently rounded final shape of the handle, the blank is first rough turned using a series of taper cuts. See photos below.

The rough turned blank is finished to final shape by smoothing with a file, and then polishing with successively finer grades of abrasive cloth. The mandrel used to hold the handle is also used to hold the screw so that one end can be turned to a dog point. The handle is completed by inserting the screw into the handle and securing it with a brass jam nut. See photos below.

Completing the Main Body Shape

The initial step to completing the main body shape is to mill the ends, top, and bottom to size. The handle end and bottom are first simple smoothed out by flycutting. Recall that the handle end and bottom were intentionally made 0.010" oversize; however, it is not necessary to remove exactly 0.010" by fly cutting - simply remove enough materiel to obtain an overall smooth surface. The top and front end should be milled to final dimensions, first by rough cutting with and end mill, and then to final size with a fly cutter. See photos below.

Once the final rectangular shape is completed, the next step is to mill the top to final shape, as shown in the photos below. Firs the cuts to be made are marked out on one side of the workpiece (note I used a blue Sharpie for layout dye); these cuts do not need to be super accurate, so simply milling to the marked lines is sufficient. First eh straight cut is milled out, and then the piece is remounted in the vise at an angle for the angle cut Using a parallel to make sure the workpiece is lined up properly). In order to get these two cuts to merge properly, I actually had to repeat this process again to "sneak up" on a clean merge.

For the back cut, the workpiece is remounted in the vise at a 45° angle and milled down to the marked line (see photos below).

In the next step, the brass sides are removed and the core is layed out for cutting and milling. First the core is sawed into two pieces; note that the cut is marked on the bootom of the core, midway between what will become the final pieces.

There is a relatively large amount of material to be removed from the core pieces, so the bulk of the part to be removed is rough sawn away first.

For the larger piece, I first put the piece in a clamp, and then held the clamp in a bench vise. I cut with a hacksaw for better control - I didn't want to risk using the bandsaw and having it veer of course. I also marked the dies of the piece as a guide to where the cut should go, leaving room for final milling. This was a successful cut, but of course quite time consuming.

Of course after I had done this, I realized that there was a better and easier way: use a slitting saw!

The piece was set up in the milling vise using an angle plate, and the waste was cut off with a slitting saw (sawing both the front and back due to the width of the piece). It was necessary to clamp the piece rather high in the vise, to allow clearance for the saw, so I took shallow cuts. It was a somewhat lengthy process, but overall much easier than the hacksaw, and much more accurate.

For finish milling the piece was remounted (to provide a firmer grip), again using an angle plate, and then rough milled to close to the marked line. A flycutter was then used to mill down to the marked line and provide a smooth finish.

Making the Lever Pin

The lever pin was made from a length of stainless steel rod (but almost any type of hard metal rod will work - the choice is mostly esthetic). First one end is turned to a diameter and length to fit the hole in the side piece. The more of the rod is turned down to the finished diameter (do this a short section at a time to keep the rod from flexing while turning). The rod is then cut off slightly oversize, flipped around in the lathe chuck, and the other end of the pin is turned down to fit the hole in the side plate; theis end can then be fined tuned for length so that it fits snugly between the two side plates, and the pin ends are flush with the outsides.

Making the Blade

The blade is made from O-1 (oil hardening) tool steel. As I was not sure beforehand what the appropriate blade thickness should be, tried tool steel in both 1/8" and 3/32" thickness. As it turned out, the 3/32" thickness was the better choice. As the process is essentially the same for either thickness, I will show only the 3/32" thick blade here.

First, a piece of the appropriate length is cut from 3/4" x 3/32" O-1 bar stock. A rough bevel is milled in one end by clamping the workpiece in the mill vise at a 60° angle (which results in a 30° bevel when the end is milled "flat"). To ensure an even bevel, it is necessary to level the bar in the vise using an indicator. Once the workpiece is properly positioned, it is a simple matter to mill the end until a full bevel is obtained. Next, the piece is repositioned flat in the vise, and the end opposite the bevel is drilled and chamfered - this hole is used later in the hardening process to make it easier to hold the blade.

Next, the end opposite the bevel is layed out with a rounded shape, and the end is shaped on a grinder. The piece is now ready for hardening.

Hardening the Blade

To harden the blade, it is heated to orange heat until it is no longer attracted by a magnet. I used a MAPP gas torch, which was sufficient to heat at least 3/4 of the blade, with a long length of iron wire through the hole in the blade to hold it. Once the piece is sufficiently heated, it is quenched in oil (I use plain motor oil); the piece is dipped fully into the oil and "stirred around" to cool it rapidly and evenly.

After hardening, the piece needs to be tempered. The oil is wiped off the piece, and scale from the hardening process is removed with a deburring wheel or abrasive cloth. To temper it, I wrap it in steel wool and aluminum foil and place it in a toaster oven set to maximum heat (450°F) for one hour, and then leave it until it is cool.

The final step in preparation of the blade is sharpening or honing. As honing is a standard process, I do not show it here, but I have provided links at the bottom of this page for those who would like more detail. In addition, I found it useful to make a honing guide to help with the sharpening process - see Thumb Plane Honing Guide for more details.

Making the Lever Cap

I ended up making two different styles of lever cap - both of these are detailed in the plans, but I will show the making of only one here. The first one I made was a fairly simple flat piece; although this worked, it was difficult to position properly. I therefore made a second, slightly more complicated lever cap with a step in it to position it against the lever pin. The second piece also had the benefit of being slightly thicker, which allowed for more threads for the adjustment knob.

A piece of 3/4" x 1/4" brass bar of appropriate length was milled flat on one side, first with an end mill, and then with a fly cutter (for improved finish). Note in the photos below that a piece of scap aluminum is inserted in one end of the vise jaws to even the vise calming pressure.

The piece is then flipped over and milled to (almost) correct thickness, the end of the piece is squared up with the end mill, and the top is finished with a fly cutter to correct thickness (final 0.002"). Next a step is cut into the top, again finishing with the fly cutter. Finally, the hole for the adjustment knob is drilled and tapped.

To complete the piece, it is repositioned in the milling vise to mill a slight bevel on one end.

Adjustment Knob for Lever Cap

The adjustment knob for the lever cap is a straightforward job of knurling, turning, and threading. After knurling a section of brass rod, the end is turned down for a #10-32 thread, and a chamfer is turned on the right end of the knurl. The turned down section is threaded (I just used a threading die), and the knurled section is parted off. Note that before completing the parting, the left end of the knob is also chamfered.

Final Assembly

With all of the machining work complete, the plane was completely disassembled and cleaned with degreaser. Before re-assembly, the axle for the handle was lightly greased with white grease. The side plates were then screwed on, using medium strength thread locker on the screws (the idea being to keep the screws from loosening during use, but still allow future dis-assembly if necessary).

Extra

To complete this project, I made a wooden box to hold it, along with the honing guide (with hex wrench) and the second lever plate. There are no plans for the box - I just made it up as I went along, but here are a few comments on it:

• The box is made from ~1/4" thick pine, made from re-sawn 1/2" pine boards.

• All box parts are glued together with wood glue

• There is green felt in the bottom of the box, held in place with 3M spray adhesive

• The top of the box is a sliding fit, and is completely removable, and can be stored in slots in the bottom of the box

That's all folks! Hope you liked it.

References

Not surprisingly, I found many links to thumb planes on the Internet, some more useful than others. Below is a list of the links I found most useful:

• Crafting A Plane With The Veritas Wooden Plane Hardware Kit Watch This Video

  • [Video] Step by step build instructions for wooden plane.

• DIY Finger Plane

  • Some nice pictures here, but not much else.

• How I make my mini-planes - YouTube

  • [Video] Wooden body plane, with blade made from O-1 tool steel.

• How to Build a Scrap Wood Finger Plane with a Chisel Blade / Rockler How-to

  • The title pretty much says it all.

• Make a Wood Thumb / Palm Plane - YouTube

  • [Video] Wood thumb plane with metal frog.

• Planes

  • No build instructions, but many good pictures.

• St James Bay Thumb Plane kit

  • No build instructions, but many good pictures.

• ThumbPlanePlans.pdf

  • Plans by Mike Freda for a wooden thumb plane in PDF format

• Wood Finger Planes

  • No build instructions, but some good pictures.

• Wooden Thumb Plane

  • Step by step instructions for wooden plane with blade made from old file.

Sharpening a planer blade is an art in its own right; here are some links on the process:

• • How to Sharpen a Handplane Iron : http://www.startwoodworking.com/post/how-sharpen-handplane-iron

• Plane Blade Sharpening Made Easy : http://www.craftsy.com/blog/2014/04/how-to-sharpen-plane-blades/

• Sharpening a Plane Blade : http://villagecarpenter.blogspot.com/2008/02/sharpening-plane-blade.html

• Sharpening Angles for Bench & Block Planes : http://virginiatoolworks.com/2013/02/16/sharpening-angles-for-bench-block-planes/