Monday, March 18, 2013

Hexagonal Aluminum Handles

today I just want to share a little idea about tool-handles, I came across lately. In a hardware store I found hexagonal aluminum rods in the size of a classical wooden pencil and I thought, these would make some nice tool handles. The wrench size of these rods is 7.0 mm. So I cut off pieces with a length of 10-11 cm from these aluminum rods like you can see on the following picture.

Then I drilled an axial hole on each side. In fact I made three versions with holes in 1.0 mm, 2.0 mm and 3.0 mm size for holding 1mm, 2mm and 3mm tool tips like you can see on the following picture. I confess it is not easy to get the holes exactly centered. After that I drilled in small holes with a diameter of 2.5 mm in at a 90 degree angle to the first hole and about 0.5 cm from the end of the rod. In this holes I cut threads with a m3 size, so headless set screws with m3 size will fit in.

These set screws will fix the tool tips inside the handle. Of course you don't need the whole side-holes-and-set-screw thing. Instead of that you just can glue the tool tip inside the axial holes with metal glue, but I prefer the set screw solution because it gives me the option to change the tool tips and to adjust the length of the tool tips.

Finally I bevel the ends of the tool handles because I don't like these hard edges on my tools, but this is more an aesthetical aspect then a technical need. I do this by fixing the rod into an electric drill set it into rotation and carefully grind it down with an electric file or a usual metal file.

Finally the whole thing looks like that:

What you can do at last is to give the handles a nice and smooth surface by using fine grinding paper and a polishing wheel (I still have to do that).

Ah, I nearly forgot to point out a main advantage of this tool beside the fact that it feels like a pencil. It didn't accidentally roll from your desk because of the hexagonal shape and this is a big point, especially if you use small and delicate tools that could easily be damaged.

So I hope you like this idea. See you next time.

Sunday, March 17, 2013

A simpler way to make the Schellert-Tool Handle

Hi, I just want to share a much simpler way to do the Schellert-Tool handle. 
To remember: The "Schellert-Tool" is a tool tip holder with exchangeable sculpting tool tips. 
The sculpting tool tips are fixed into aluminum clamps that are taken from hobby knifes to form the endparts of the Schellert-Tool handle. You can find an in deep explanation about building the Schellert-Tool here (link).

I confess, it's not the simplest tool to build. Especially cutting the threads into an aluminum tube might be challenging even if you own the needed thread cutter and impossible, if you haven't one. So I thought about a way to make this tool easier to build. The easiest way would be to find somewhere an already cut thread-piece that could be used for that. But I had no luck in finding such a pre-fabricated piece untill lately:
Now I've found in a hardware store a simple and cheap piece that is ideal for my needs. In German this thing is called "Messing-Spreizd├╝bel" and the translation into English I found so far is "brass expansion bolt" or "brass straddling dowel". On the picture you can see this fine little thing.

This brass dowel has a m5-thread and is made for drilled holes of 6 mm diameter. This is ideal in combination with an aluminum tube with an outer diameter of 8 mm and an inner diameter of 6 mm (material strength: 1 mm), like the one I used for the original Schellert Tool (link). You don't even need to glue a second smaler tube into 8 mm tube, because the brass dowel will take that part.

So all you have to do is to cut off a pice of the 8/6 mm aluminum tube with a length of about 7.5 cm. The easiest way to do this is by using a tube cutter, that makes perfectly straight cuts (look here). Then all you have to do is to put one brass dowel into each side of the tube. Be sure to push it a few mm below the edge of the aluminum tube. Otherwise the clamp-piece wouldn't fit in later.

In some cases the brass dowel is a little thicker than the inner diameter of the aluminum tube. In this case you have two options. You can widen the aluminum tube be using a drill of 6.1 or 6.2 mm. The other option, especially if you havn't got those special-sized drills is to grind down the knurled surface of the brass dowel. The easiest way to do this is to fix the brass dowel into a power drill and press it slightly onto a oiece of grinding paper while rotating. You can also use a metal file and grind down the brass tube by hand.

To fix the brass dowel into the aluminum tube you have also 2 options:
You can simply glue in the brass dowel into the aluminum handle with a good metal glue or you can fix it by using a 5 mm hexagon socket set screw like you can see on the next picture.

That's all. All you have to do ist to take the clamp-parts of two hobby knifes (Martor, ecobra etc…) and screw it into the tube ends.

Note: The brass dowels I use have a m5-thread. into the threads of these brass dowels you can only fit the clamp-parts of the hobby knifes that have also a m5-thread. The m5-sized screws and threads are standard in Germany where I'm from. In other countries there are other standards like "unc" in the United States for example. There are Hobby knifes available with m5-threads from Martor and Ecobra for example. I know, that other hobby knife have a UNC 10-24 thread, like x-acto, I think (I told a little bit more about this here)
So be sure to use hobby knifes with an m5 thread. You can find these knifes and also the brass dowels on google/ebay.