Modifying a Hitachi depth adjustment device

I recently had a Hitachi planer equipped with a “shaper’s barrel” shipped by Shapers Australia. Theirs come in 220V and the price was not much more than that of the barrel itself, so…

Then I started to think about a way to make the depth adjustment go from nothing to “full throttle” in one easy touch. After some brainstorming, I came up with a very simple yet effective way of doing it. As I think it can be applied to all planes with a front shoe moving vertically (makita and others), here is the weirdo:

As you can see (or so I hope) on this photo, the knob has been removed and a nut has been locked with a small bolt going through both axle and nut in such a position as to have front and rear shoe in “0” position. This way, the barrel or blades do not touch the foam. A new knob has been mounted on a metal plate in front. This metal plate acts as a lever: when you push the knob down, the shoe axle goes up (and so does the front shoe, of course). In order to create a “grasping” motion, I used a curved piece of rod that goes through the planer’s body and is locked in place with another small bolt going through it.

This is how it works: my fingers grab the rod bar in front, while the palm of my hand shelters the knob. If I grasp my fingers, the knob goes down and the front shoe goes up. When I stop grasping, it comes back to the “0” position. (I forgot to say that I had to replace the original spring -too powerful- by a softer one). It does take some getting used to, but you master it quickly. I shaped another SUP this afternoon using the system and it came out OK.

looks good. Bigger pictures would be great, as would pictures of the parts you made, prior to installation. This started out as a stock Hitachi, then, without the “Clark” modifications?

Might I suggest you also post it as a Resource in the Tools section?

Yes, this is what the planer looked like in the beginning:

I’ll try and post bigger and more detailed pictures tomorrow (feeling lazy tonight… going back to the shop, cleaning the planer, taking it apart look just too much for me…)

OK, let’s try to have bigger and more detailed photos, going the Imageshack way:

Here are all parts:

  • the front shoe with its threaded rod (axle) and the new custom-made spring (in the back ground, the original spring -right- and the long spring in which I cut the new one with a grinder -left-). Notice, if you can, that the threaded rod has been drilled through (just above the spring top).

-in the foreground, the nut (drilled through, too) and the 4 MM bolt and nuts to go through both nut and shoe axle.

-right are the metal part on which a gear handle knob has been bolted (front) and an over-bore hole has been drilled (back), the latter is to allow some play when pushing the “lever”. And a washer, to go between the lever and nut.

In this picture, all above parts have been assembled “in the white”. The only missing part being, well, the planer itself…

This shows the curved rod that’s been drilled through and the bolt used to hold it in place. The bolt goes through the original thread in the planer’s body that is supposed to hold a side-guide in place (when using one). Actually, the curved rod IS the original side-guide that’s been cut, grinded and drilled… (Always use what’s easily available before buying anything.)

The “handle”, fully assembled.

Some more bigger pictures:

Great mod on the planner. I like the idea of sqeezing compared to twisting to make the adjustment. I think it would feel more natural to me.

Oh I get it. . .

I was wondering how did it all work . . . at first I was, “how can it go up and down when the bolt can’t turn . . . so the handle doesn’t turn.”

But examining the pics after 5 minutes . . . the softer spring allows the foot to move easier, the knob with the metal plate placed where the depth adjustment dial used to be acts as a lever. So when you squeeze down the handle it pushes the knob down, which pulls the foot up and you adjust it by that.

That’s pretty ingenious.

Impressive… Good job!



Thanks to all for the kind comments. I will just add that you get used to adjust your grasp on the knob to the noise of the barrel on foam. Sooner than you’d think, it just becomes natural. I never used a Skill 100 with “on the fly” adjustment but I guess that people who do must shape to the sound, too. Am I wrong?

I really like this, Balsa. Is the new spring so loose that you don’t get any fatigue?

I think the ‘deadman’ type feature is excellent too - as soon as you let go, it goes to 0 cut.

Thanks for all the good photos!

Using the sound as a cue sounds good (pun intended) :slight_smile:

I. like Benny, was wondering about fatigue in the hand from holding the tension of your setup?

Looks like a very good mod though balsa. I have just started using a planer myself (cheap Black&Decker) trying to use it as Bill Barnfield talked about in the planer thread, by just using my eye and watching the shadows of the bands as they emerge. Not too bad so far. I would like however to get a moded planer, or to mod one myself, for the depth cut as well as the handle and the exhaust port. I find that the handle in the ‘down’ angle doesn’t give a lot of control over the angle of the planer. The one I am practicing with has a side exhaust port and it gets in the way alot, and can even cause slight tilting on the side that it is on if I am not careful.

I will do some research in the archives, but your setup has given me an idea for depth adjustment. It seems like it could be a good one, as long as the spring were to be weak enough to avoid fatigue in the hand.

Johan, the spring looks OK. I didn’t feel any noticeable fatigue in my hand. The thing still has to retain some power to bring back the shoe to its original “0” position. Besides, the stroke is quite small, something like 5 MM. The challenge is much more about setting a given depth of cut and keeping it the same depth all along when needed (for skinning). But this can be easily achieved, when needed, by adding some wedge between the lever and washer. This way, you may set it at, say, 3 or 4 MM and do exact same depth passes. Of course it would have been great to incorporate this into the modification. Oh well, better next time…

As I said above, I think that this can be easily applied to all types of planers using a vertically sliding front shoe, with minor adaptations.