Sunday, January 5, 2014

A little bit more about the adze.


The adze is finally out of prototype phase and swinging into production.  I've been delaying writing more about it until everything was finalized, which it finally is.  I got a lot of great feedback about the tool at Woodworking in America, and Pete Galbert and I went back to the drawing board to make a few design tweaks that have really upped the performance of the tool, mostly the result of a subtle change to the curvature of the blade and the degree of external bevel.  The first batch of twelve tools is in production, so I thought this would be a good time to provide a few more specifics about the adze.


The main structure of the tool is a steam bent hickory handle joined to an East Indian Rosewood head.  The tenon on the end of the handle is tapered at the bottom of the joint, flared and double wedged from the top, and assembled with epoxy.  It's like a chair joint on steroids; rugged, and it has to be to take the abuse this tool is subjected to.

A batch of adze blades awaiting heat treatment with a couple of un-forged steel blanks.

The blades are forged from 1/4" O1 tool steel,  flared out at the cutting edge (1 3/4" from point to point after it is bent).  The sweep of the edge is a two inch radius, enough curve to keep the corners from digging into the work and flat enough to be able to leave a surface that is relatively smooth and quick to clean up with the inshave or travisher.  The blades are drilled and countersunk for a hex flathead machine screw that secures them to the rosewood head.

An allen wrench loosens the blade.

Blade removed for grinding or sharpening.

The machine screw threads into a cross dowel which is inset into the side of the head.  When I assemble the blade and the head, I ever so slightly offset the machine screw hole in the head toward the shoulder that the back of the blade rests against.  As the machine screw tightens down into the countersink, the blade is forced tight against this shoulder, similar to the way a drawbored pin draws a tenons shoulders tight.  This eliminates any tendency of the blade to twist in use.  I remove the blade for grinding and coarse sharpening, like removing nicks from the edge.  For minor touch ups, I leave the blade in place.

This adze is lighter than most adzes of European descent, closer in weight to the elbow adzes of the Pacific Northwest.  Weight and balance of the tool was a major design consideration and one of the reasons for the mountain of adze prototypes that I made.  I inserted weights into different portions of the head to experiment with the total weight of the tool and the amount of weight in front of and behind the handle.  The final version has a thicker blade than my prototypes which eliminated the need for added weight.  The thicker blade also gave the tool the forward balance that I knew I wanted as a result of my prototyping.  Forward balance makes the tool track more intuitively in the cut and also puts all the weight right where the tool is working.


The action of the adze changes dramatically depending on where and how the handle is gripped.  As a rule of thumb the closer to the head the handle is gripped, the more aggressively the tool will dig into the wood.  The closer to the end of the handle the tool is gripped, the less the tool bites and the more easily it clears chips.  Each user's sweet spot to hold the handle will be slightly different, corresponding to differences in forearm length, style of swing, height of work surface, and the desired cutting action.  The red rubber band on the handle slides up and down and functions as a reference point for repeated hand placement.  This is especially helpful when learning to use the adze.  Does that rubber band look familiar to anyone?

North Atlantic Lobster bands.  Welcome to Maine.

To use the adze most effectively, a relaxed grip is essential.  This allows the tool to pivot in the hand at the end of the stroke, which helps to clear chips instead of digging, digging, digging in.  There are times that you want to dig in, but that's another blog post.  I start my grip by wrapping the thumb and index finger at the top edge of the band.  I also wrap my middle finger around the tool, while my ring and pinky fingers remain relaxed.


The following pictures show how much this grip allows the tool to pivot in the hand.

Adze pivoted back in the hand.
Pivoted forward.

Please note that the my wrist position is the same in both of these photos.  The main portion of the swing comes from the elbow joint which generates power and provides gross movement of the adze along an arc.  Imagine if the tool was gripped tightly and there was no movement in the wrist.  In this scenario, the adze would only be able to cut along that one arc, with a radius originating at the elbow joint.  Allowing the tool to pivot in the hand slightly allows the user to adjust the arc on which the tool is traveling to cut a wider or tighter curvature, as desired.  Allowing the tool to pivot also seems to increase power.  I'm going to have to do a video about this!

Roughing out a complex shape like a windsor chair seat requires several types of cuts with the adze and different grips for more power or control.  I do plan to venture into video soon to better illustrate this and other techniques with the adze.  More to come.

17 comments:

  1. Congratulations on all the hard work and experimentation to get you to this point. The tool looks great and there's no doubt in my mind that it works even better than it looks

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    1. Tico,

      I'm sorry you didn't get to try it at the Lie Nielsen show in Mass. Next time. I've been thinking more about the differences in the feel of the shooting planes since I used them. I look forward to continuing that conversation again at some point.

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  2. Awesome Tim, did you get my email about being put on the waitlist for these Adzes. You sold me at WIA so if I'm not already on the list please add me.

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    1. Shannon,

      Great to hear from you. You are on the list for the adze. I'll keep you posted as I move through the list. I think yours will be in batch #2. Blades are forged but not heat treated. I bend a few handles every day.

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  3. Looks like a fantastic tool. Not to sound cheap, but I'm a poor fella, so any idea yet on a price point?

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    1. No worries about sounding cheap. I'm in that boat myself.

      The price of the finished tool is $225. Definitely not a cheap tool. If you already have an adze I would be glad to talk with you about tweaking it to increase performance without laying out the money for a new tool. Send me an email and we can continue the conversation from there.

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    2. Tim,

      I think that price is more than fair when you consider the skill of craftsmanship I know you put into your work. I think it looks amazing. Hope to have one myself at some point.

      I am eyeing that reamer first though. Got to have one of those.

      Keep it up!

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    3. I agree. A very fair price indeed. I will be saving up for one myself.

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  4. Everything looks fantastic! With the added tweaks I am sooooo ready to put it to work. I have three seats that need to be carved and they are begging to be adzed. Thanks for the update.

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    1. Ray!

      My goal was to have the first 12 done by the end of this week. That seems unrealistic now, but I am moving them through the process (and refining the process as I do). Your tool is one from this batch, and it can't wait to go to work. I look forward to getting it in your hands as soon as possible.

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  5. Hi Tim;

    Long-time lurker, first time writer. I've been wanting an adze for a long time now but have been unwilling to take the plunge due to all the conflicting advice out there. Yours looks like a sure thing. How do I get one?

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    1. Hi. What a compliment! I keep a wait list running of orders. Email me so that I have your email address and we can take it from there. Thanks.

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  6. Tim, they look great. Nice work.

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  7. Tim,

    Have you tried the adze on anything harder than pine? My present commission involves saddling seats out of hardwood (ugh!) and wondering how your adze might perform in that medium?

    Thanks,

    Rob

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    1. I have. The adze works well in medium density woods like walnut, soft maple, and cherry. When you move up in wood hardness to sugar maple, white oak, and elm, I start to want a large two handed adze.

      What wood are your seats made of?

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    2. Tim,

      Sorry for the time lapse. I wasn't notified of a reply and just remembered to check back.

      The seats are white oak and I have 8 to carve. I'm fairly new to this and Curtis told me that he had never carved a seat out of oak, but the client wants reproductions of the chairs they have had in the family for about 80 years and the originals had oak seats. So I will carve in oak.

      Do you have any input on carving the harder woods? And when you say two handed adze, I assume you mean one with a longer handle? Any suggestions on a good maker for a two handed adze?

      Thanks,

      Rob

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    3. Rob,

      Now I'm sorry for the time lapse. I missed this one coming in. White oak would be pretty much top on my list of wood to avoid carving a seat out of, but it seems that you are stuck with it for reproducing these chairs. Pete Galbert uses butternut with white oak unpainted chairs that he makes. It has a similar color and tone to the white oak and carves beautifully.

      Hans Karlsson makes a nice heavy adze with a long handle that is sold through Country Workshops. That would be my choice for a larger heavy tool.

      I would love to see pictures of the original chairs or the reproductions you are making. Send me an email with photos if you can.

      Tim

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