A recent online auction netted me a box of K20 soft fire bricks for CA$25. The photo showed maybe 5 or so bricks but in reality the box had 20 bricks, 2 of which already had heating elements!
After many hours of using the lathe, it was time to finally get rid of changing belts and install a variable speed motor. Trolling Kijiji resulted in purchasing a 2.5HP 130VDC treadmill motor.
The result, variable speed and much better finish since I can now set the speed I need instead of making do. Switching between HSS and insert tooling no longer requires getting out the 14mm wrench 🙂
I am in process of building a Jan Ridders Glass Cylinder engine and it requires T2.5 timing pulleys. I am not fond of spending money (it is a hereditary thing I think) so I intend to make my own pulleys. Originally I was going to use the fly cutter technique but with the tiny tip size I am concerned that the tool will not last cutting 3 pulleys. Continue reading
The next few parts on the Glass Engine are brass. For that I need to grind some cutting tools, the geometry for brass cutting is quite different. While I have a Quick Change Toolpost, every cutter more or less needs its own holder. This gets pricey at CA$20 each. Plus the growing collection needs a storage solution.
On YouTube I had seen an interesting solution while browsing for tool grinder videos. Luis Ally uses round tool bits for his machining. Well worth a watch. Basically you make a holder for round tool steel, and replace the ‘inserts’ as needed. Since I have a Tool & Cutter Grinder and I have 6 and 8mm round tool steel, it was just the solution.
I used some .5” square stock, drilled a 5.5mm hole and reamed it out to 6mm. Then using a slitting saw I cut a groove on one side. This allows the clamping force of the tightening screws to lock the tool bit in place.
The work head on my antique grinder is in need of some remedial work. When I measure the run-out (wobble) it is 0.006”. Might not seem like much but when you need to grind a shaft down to some size it would be great if the result were actually round!
Time for some heavy metal! The flywheel is 100mm diameter and 25mm thick. I had an ugly lump of steel that was just right for this.
The lump was setup in a 4 jaw chuck and centered as best as possible. With light cuts to avoid the thing flying out I surfaced the outer diameter to correct size.
The pulleys and shafts are fairly straight forward although there is some close tolerance required on the shafts.
Next up, the exhaust valve housing and mounting the cylinder block.
I turned the housing from some brass, I was hoping for bronze but none to be had when I was ready for it. This piece threads into the support plate, it will need some thread locker on assembly to keep it in place.
The cylinder block, which I made on my Taig in fall of 2014, was marked up for holes on 3 sides. 2 are tapped for the spark plug and carburetor, the other is the exhaust port.
With the shafts for the cranks ready, it is now time for the webs and crank pins.
The webs were machined to 25mm from 1” stock. The shaft hole was drilled to 5.5mm and then reamed out to 6mm to fit the shafts closely. They will be attached with Loctite 603 (or more likely the affordable alternative from Weicon). Cutting off went quite well, having a strong lathe makes this so much less traumatic. The webs gave me some challenges as they are only 6mm thick after cutting them off the raw stock. Holding these straight in the 3 jaw was not easy but I ended up using a piece of 6mm rod in the tailstock chuck to align the web. This let me face the second side and reach the 6mm target dimension.
With more parts to make, there are more tools to make 🙂
In making the main shaft, which mounts the flywheel and the exhaust valve, I needed to cut 3 flats 120 apart. From my stash of metals I dug out some hex and bored, then reamed for 10mm. A set screw finished that tool off. While cutting the 2.5mm slot in the end I broke the cutter.