Build - Glass tubing cutter
Glass Tubing Cutter
This glass tubing cutter is based on a design by Jan Ridders, with some modifications to simplify the build. I'm not going to go into a lot of detail here, because the build has a lot of "materials on hand" quality to it. Also, although it uses a Dremel tool for driving the cutting wheel, there are numerous Dremel models available, so there is no one-size-fits-all design.
The basic design is to use a Dremel tool to drive a metal disk with diamond grit on it, to cut the glass. There is an arrangement for a water drip to lubricate the cutting, and an adjustable v-block to hold the tubing. A stop block sets the length of the tubing to be cut.
To cut a tube, the v-block is advanced toward the cutting disk until it just starts to cut, and the tubing is rotated by hand. As the cut proceeds, the v-block is incrementally advanced toward the cutting disk with constant rotation of the tubing, until the cut is complete.
I'm happy with the build and I think it will work well for it's intended purpose (cutting glass tubing to make oilers). If you are going to make one of these, I would urge you to study Jan Ridders original design, and to take a look at some of the suggestions and comments I have made below, and mare appropriate improvements.
Basic components:
- Cutting disk : I used a 2" diameter disk, which enabled me to eliminate the belt drive arrangement used by Jan Ridders. Because of the relatively large diameter, the rotational velocity of the edge of the disk is higher, so I run the Dremel at slowest speed. I bought the disk as part of a set via ebay.com; the disks came with a couple of mandrels, but they were slightly wobbly so I just turned a new mandrel out of brass.
- Adjustable v-block : I made this out of UMHW plastic, with stainless steel guide rods and brass all-thread for the adjustment screw.
- Base : I used birch plywood, finished with two coats of spray enamel and a top coat of clear acrylic. I raised the base on wooden legs and cut a hole in it to allow the water to go through; a small can collects it underneath.
- Stop block : Made from red oak, coated with spray clear acrylic to waterproof
- Water tank : Made from a thick plastic drinking bottle, cut in half on the table-saw. I used a needle valve from local plumbing supply and some plastic tubing to deliver the "drip" to the cutting disk. The stand for the tank is made from birch plywood, coated with spray enamel.
Close-up of the Dremel and cutting wheel (toward the rear), and the adjustable stop-block (a couple of screw clamps screw into threaded inserts in the base).
Note the hole under the cutting disk to allow water through to the collection can. The water collection system works fairly well, but the rotating disk tends to throw water backward, so I may make a small "fender" to divert it to the collection can.
For the base I used 1/2" birch plywood (painted with a final coat of clear acrylic) where Jan Ridders used plastic. Plastic would have been preferable, if I had any. The painted wood is working so far, although I have some concerns about how ell the paint will hold up over the long term; for now I am careful to dry things out as much as possible after use.
Close-up of the adjustable v-block.
I milled the V in the UHMW plastic block using a router bit in my mini-mill. As I only had a 1/2" V-bit, I had to make a series of cuts to get the V to the width and depth I wanted.
First two test cuts (on approx. 0.3" diameter glass tube). The two cut pieces are sitting on the water collection can (turned upside down).
Very little water was needed to make the two cuts - the water in the can was about 1/4" deep.
More test cuts - I cut the end off a larger diameter glass tubing (approx. 1/2" diameter) and the bottom of a pickle jar (approx. 3" diameter). For scale, that's a 3" rule just behind the glass tubing in the photo.
The 3" diameter jar cut worked out OK, but the V-groove was just barely large enough to work. If I was going to cut larger than 2" diameter routinely, I would probably make a wider V-block.
I should note that the edges of the cut in the 3" jar were quite sharp, so I used some 400 grit abrasive cloth to "chamfer" the cut end and remove the razor edge.
Another view of the cutter; the small can (a tuna fish can) slides under the hole when in use, to collect any water from the drip feed.
Still another view of the cutter.
Closeup of the water tank. I purchased a needle valve from local plumbing supply, and made a threaded brass adapter to connect it to the tank (it screws into a curved aluminum plate with a rubber gasket on the inside, and is held tight with a nut on the outside). The spout is a piece of semi-rigid plastic tubing which I heated with a hot-air gun and bent into shape.
As noted earlier, the base is made of two pieces of plywood (painted); the tank simply sits in the recess.
Close-up of the V-block and the cutting wheel. The stainless steel guide rods are simply pressed into the moving V-block, with clearance holes drilled in the stationary block. A threaded brass sleeve for the screw adjust is pressed into the moveable V-block.
The V-block is positioned to just clear the cutting wheel. The rear stationary block is slightly shorter than the moving V-block, so there is more clearance at the rear of the cutting wheel.
A view from the back. The Dremel is mounted on a piece of 3/8" thick aluminum plate which I milled out to fit the Dremel. An aluminum post and clamp hold the Dremel to the plate, which is fastened to the base via two threaded holes on the under side.
As an experiment, I made a small "fender" out of aluminum sheet from my scrap box (simply held in place with a weighted block in this picture). I found that this does reduce the spray a bit, but I will need to enlarge the drain hole a bit to catch the runoff. I will probably make the fender a bit larger to cover more of the cutting wheel as well.
I may also remove the rear block temporarily and shorten it a bit more on the cutting wheel end, to make more room for the fender.