Ultimate Home-Made Dremel Sander / Carving Bits

This Instructable will show you how to make your own sanders / carving bits from an inexpensive grinder wheel. The results will blow away the temperamental Dremel sanding drums because they can be used at higher speed with perfect balance and concentricity - no more broken or worn out sanding bands! Oh yeah - they are also re-sharpenable, and can be made larger for tools such as die grinders. They can also be in different shapes such as cylinder, ball-nose, dovetail, v-wheel, flame, or other shapes as needed. Watch my video showing how the bits are made and demonstrated first. If you like what you see, please subscribe to my YouTube channel.

If you would like to try a bit like this before investing in new tools to make your own, you can use the tan or orange Dremel grinding bit that is typically a little smaller than the 1/2" rubber drum sander.. Dress the grinding bit by spinning it at low speed against a diamond bit (preferably larger diameter and coarse) spinning at high speed in an electric drill in a way so that the rotation axes are crossed, and the scratches formed on the bit cut along the length of the grinding bit or at an angle. You can also use a diamond blade for an angle grinder. The objective is to make the grinding wheel as rough as possible while also truing it to be perfectly concentric. You don't need to remove much material from the grindstone to sharpen it. Try carving a scrap piece of pine before and after the dressing process to see the difference it makes.

Caution - do not use this for making large diameter cut-off wheel type bits. Those types of wheels have fiberglass mesh embedded in the wheel for strength. Regular bench grinder wheels do not have this reinforcement.

You will need the following tools and supplies:

1. Harbor Freight 60-80 grit white aluminum oxide bench grinder wheel or similar.
2. 3mm diamond hole saw for drilling hole for shank
3. Various sizes of diamond hole saws to cut plugs to the desired sizes.
4. Gel type superglue for bonding shank to grinding wheel material.
5. Superglue accelerator.
6. 1/8" welding rods or used-up stubs.
7. Hack saw for cutting shank material to length.
8. Coarse diamond bit or wheel for dressing the grinding plug.
9. Safety glasses.
10. Water.
11. Drill Press
12. Bench grinder with wire wheel for cleaning shank material.
13. Dremel rotary tool or similar with 1/8" collet or chuck.

Please find links to specific tools on my website.

Choosing the right grinder wheel to make the plugs from is critical. I bought a white aluminum oxide 60-80 grit 8" x 1" from Harbor Freight for $9.99, and I lucked out because this wheel seems to be perfect for this project! I also tried a 24 grit gray aluminum oxide wheel that didn't work well at all. You can feel the face of the wheel and tell if the abrasive particles feel sharp or rounded - the sharper the better! The grit size should be a coarser grade, a smaller grit number designates a larger particle size the same way as sandpaper. I haven't experimented much with finer grit wheels, but I would expect them to cut slower with a smoother finish - and more likely to burn. The grinder wheel is porous and will soak up water like a sponge. Soak the wheel in water for a few minutes before drilling it, the water absorbed by the wheel is enough to keep the diamond hole saws cool while cutting. Make sure the axis of the drill press is perpendicular to the table before starting. Cover the drill press table with a plastic cutting board to help keep it dry.

Position the grinding wheel on the table so that a plug will be formed by the diamond hole saw will be just inside the outer edge and clamp it to the table with a spring clamp. Drill the hole for the shank first with a 3mm diamond hole saw at low speed. Stop drilling perhaps 1/4" from going through. Now without moving the wheel, remove the 3mm bit and insert the larger hole saw to cut the plug diameter concentric to the hole for the shank. Don't worry if the shank hole is a little off center, the bit will be trued up concentric later. Stop cutting the plug just before breaking through the last half millimeter so the plug doesn't get stuck inside the hole saw. Pry the plug from the wheel and it will easily snap off.

Check to see if the shank material will fit easily, the 3mm size is a tiny bit smaller than 1/8" (3.175mm). Ream the shank hole with a diamond bit to enlarge the hole so the shank is an easy fit leaving a little room for glue. Finally, carefully spin the remaining water out of the plug by allowing it to spin with the reaming bit fully inserted and increase speed slightly until all the water is slung out of the plug.

The best material I found to use for 1/8" shank is a piece of 1/8" welding rod with the flux removed. Break any flux coating with a hammer without bending the rod, and use a wire wheel to clean off any remaining flux or rust from the rod. Used up welding rod stubs should be just long enough to be usable. Measure the depth of the hole in the plug + depth of collet or chuck + desired standout to cut the shank to length. Keep the standout to a minimum - no more than 1/4" to reduce vibration. Remove the burr from the end to prevent damage to the collet, and chamfer the end. Roughen the portion that goes inside the plug to improve glue adhesion. If you don't have a source for welding rods you can use roofing nails as a shank, but these are not as smooth or round as welding rod material, and are more likely to need truing each time the bit is put into the chuck or collet.

Glue the shank into the plug by squeezing some GEL TYPE superglue into the shank hole. Spritz the roughened end of the shank with accelerator and insert it fully into the plug. There should be just enough glue to squeeze out a little. Allow the glue to set a few minutes before continuing. The gel type glue is needed because a thinner viscosity glue will soak into the porosity of the plug. I have also tried epoxy to adhere the plug onto the shank, but found that it wasn't strong enough. Maybe my epoxy was old or bad?

If you have some good 1/4" steel rod you can make larger bits for a die-grinder.

After the glue has dried, insert the shank into your Dremel and run it at low speed against a diamond bit spinning at high speed in a drill press or bench grinder with the two axes at a right angle. This will quickly cut down the high side to make the bit concentric as the diamond cuts all the way around the bit. Now you can shape the bit however you like as a cylinder, ball-nose, dovetail, etc... Bits for a Dremel should not be much larger than 1/2" (12mm) in diameter for safety concerns. For best results, use a diamond dressing bit that is coarse and has a large diameter. The dresser bit should make scratches that run along the length of the bit. Feel the texture of the grinder bit after dressing it and you'll develop a feel for whether it's sharp or not. The bit I used in this photo is a 60 grit vacuum brazed cylinder that is used for granite or concrete, these are typically a coarser grit than an electroplated bit.

The 8" diameter wheel has a maximum speed rating of 3600 RPM. Of course a smaller diameter wheel would have to spin much faster to match the G-force of the original 8" wheel spinning at 3600 RPM. Using an online Relative Centrifugal Force calculator shows that a half inch diameter (6mm radius) would match that centrifugal force at around 14810 RPM. I have run my bits much faster without any explosions. Here is a link to the RCF calculator that considers radius and rotational speed. The formula is a 2nd degree equation, so doubling the speed multiplies the force 4-fold. Wear safety glasses and be careful!

Your new bit is ready to be tested. While sanding bands work best at the low end of the speed range, these bits become more aggressive with higher speeds. Clamp the collet nut tight before using. Notice the lack of vibration - the bit will be balanced much better than a drum sander and can be used at much higher speeds. Use a piece of softwood such as pine or cedar to test the bit. Harder woods can also be shaped with the bit, but might need the speed reduced to prevent burning the wood. With a little practice sharpening the bits, they can be made to be more aggressive and efficient without burning the wood. Naturally, being made from grinding wheel material, the bits can also be used on metal.