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Hand Crank Disc Sander
Hand Crank Disc Sander
Some tools you just fall in love with after one use. The Alberti Design disc sander was one of these tools. It's a deceptively simple and seemingly low-tech machine: an 8" disc sander wheel without a motor that instead is operated by a simple hand crank. The tool is finely made, allowing for a wide range of adjustment and fixturing, and has a tremendous mechanism for allowing multiple discs and hones to be easily and swiftly swapped out to suit the task at hand. The advantage of a machine like this is that it allows the operator to very carefully remove small amounts of material at a time, making for seriously smooth and precise finishing. The delicate touch it allows the operator to impart to the work is both tactile and controlled. A few of my colleagues own these, and using them for fine adjustments on bridges, soundposts, and other small delicate fitment jobs has been incredible.
The only thing which prevented me from getting one myself was the cost. Alberti Design's machine (now on its second iteration) is indeed amazing and in my opinion more than worth its weight in gold as a precision tool. However, I couldn't really afford one, and for outfitting my home shop which is not high-capacity output at this time, cost was a factor. It was also something that, in the back of my mind, I felt I could potentially create or modify out of an existing machine.
For many years, I have had this kicking around in the back of my mind. As my home shop was coming to fruition in early fall of 2020, I got serious about the sander.
Making a precision tool "from scratch" is a non-trivial endeavor, especially a tool which requires multiple surfaces to be square and square to each other, yet robust enough to be handled and used daily. I kept coming back to the idea of modifying an existing powered bench top disc sander: this would already have a disc and table mounted in the correct orientation. But nearly all powered disc sanders have the disc mounted directly to the motor shaft, meaning that if you just remove the motor, there is no bearing block or support to hold the sanding wheel in orientation. Adding this would be heavy metal fabrication, which I am not outfitted for.
My mind turned towards belt-drive machines, or antique machines which would run off a central shop line shaft by means of a belt and pulley. I finally hit upon just the thing: The Delta Homecraft. This 1950's era DIYer's dream consisted of a table pedestal with an integral electric motor which could be used to power special attachments like a table saw, jointer, drill press, and even a small disc sander. The motor and all attachments had a pulley wheel, allowing them to be swapped out and connected using a belt drive. A little more digging, and I found the sanding attachment was semi-commonly available. I spent several months sifting through listings to eventually find a sander unit that was complete and struck an acceptable ballace between condition and cost.
The machine is fairly straight forward: an 8.5" diameter cast iron disc with a removable shaft rides in a pair of bronze bearings mounted on a cast iron pedestal. The pedestal has an adjustable table mounted to it, and the whole thing mounts to a cast iron base. A pulley wheel is attached to the other end of the wheel's shaft, which would connect to a motor.
My idea was to remove the pulley from the back of the sander, and replace it with a hand crank. The hand crank I picked up was from a large mill or lathe, and I chose it as it was cast to include a counterweight, allowing for smoother rotation in use. I made a few modifications to it to shorten the length of the center hub and tap for a new grub screw (to bring the hand wheel closer in to the central pedestal), and also slightly shortened the existing shaft of the sander to accommodate it.
Another add-on I wanted to include was a brass drip-feed oiler. The sander's bearings are not sealed, and there was a small hole and simple oil cup present on the top of the bearing block to allow for occasional lubrication. An adjustable drip-feed oiler is absolute overkill, but I love the aesthetic, and it gives the machine a very early 20th century industrial look. I drilled out the oil hole in the pedestal, and tapped it to accept a lovely 100 year old Lunkenheimer "Pioneer" No. 0 brass oiler, which has a great scale proportion to the rest of the machine.
I knew I wanted to refresh the original chipping and damaged paint, and finally settled on a color combination of black and a reddish-brown. I further trimmed out the machine with new brass nuts and washers on stainless steel studs (including rubber shock-mount washers between the cast iron pedestal and base), and some brass washers I custom made to sit between the front and back of the bearing block and the attached handle and sanding wheel.
For some added flair, I made a wooden base from a plywood center section and some beautiful flamed maple quarter round molding I found amongst the usual trim at a local big-box hardware store. I used India ink to blacken the plywood, and French Polished the molding to give a warm antique look.
The last very important detail was the abrasive disc for the sander. As 8.5" is a fairly uncommon size for sanding discs, I bought some larger and readily available 12" sanding discs, and cut one out to fit the machine.
I could not be happier with how this machine turned out. It operates incredibly smoothly and sweetly, imparting excellent control and long "coasting time" after giving the wheel a spin. The aesthetics are exactly what I was hoping for: a machine that looks industrial but from another time
I know this sander will see a lot of use in my shop, and I look forward to putting it to work. I'd love to make another one, let me know if you're interested!
Some tools you just fall in love with after one use. The Alberti Design disc sander was one of these tools. It's a deceptively simple and seemingly low-tech machine: an 8" disc sander wheel without a motor that instead is operated by a simple hand crank. The tool is finely made, allowing for a wide range of adjustment and fixturing, and has a tremendous mechanism for allowing multiple discs and hones to be easily and swiftly swapped out to suit the task at hand. The advantage of a machine like this is that it allows the operator to very carefully remove small amounts of material at a time, making for seriously smooth and precise finishing. The delicate touch it allows the operator to impart to the work is both tactile and controlled. A few of my colleagues own these, and using them for fine adjustments on bridges, soundposts, and other small delicate fitment jobs has been incredible.
The only thing which prevented me from getting one myself was the cost. Alberti Design's machine (now on its second iteration) is indeed amazing and in my opinion more than worth its weight in gold as a precision tool. However, I couldn't really afford one, and for outfitting my home shop which is not high-capacity output at this time, cost was a factor. It was also something that, in the back of my mind, I felt I could potentially create or modify out of an existing machine.
For many years, I have had this kicking around in the back of my mind. As my home shop was coming to fruition in early fall of 2020, I got serious about the sander.
Making a precision tool "from scratch" is a non-trivial endeavor, especially a tool which requires multiple surfaces to be square and square to each other, yet robust enough to be handled and used daily. I kept coming back to the idea of modifying an existing powered bench top disc sander: this would already have a disc and table mounted in the correct orientation. But nearly all powered disc sanders have the disc mounted directly to the motor shaft, meaning that if you just remove the motor, there is no bearing block or support to hold the sanding wheel in orientation. Adding this would be heavy metal fabrication, which I am not outfitted for.
My mind turned towards belt-drive machines, or antique machines which would run off a central shop line shaft by means of a belt and pulley. I finally hit upon just the thing: The Delta Homecraft. This 1950's era DIYer's dream consisted of a table pedestal with an integral electric motor which could be used to power special attachments like a table saw, jointer, drill press, and even a small disc sander. The motor and all attachments had a pulley wheel, allowing them to be swapped out and connected using a belt drive. A little more digging, and I found the sanding attachment was semi-commonly available. I spent several months sifting through listings to eventually find a sander unit that was complete and struck an acceptable ballace between condition and cost.
The machine is fairly straight forward: an 8.5" diameter cast iron disc with a removable shaft rides in a pair of bronze bearings mounted on a cast iron pedestal. The pedestal has an adjustable table mounted to it, and the whole thing mounts to a cast iron base. A pulley wheel is attached to the other end of the wheel's shaft, which would connect to a motor.
My idea was to remove the pulley from the back of the sander, and replace it with a hand crank. The hand crank I picked up was from a large mill or lathe, and I chose it as it was cast to include a counterweight, allowing for smoother rotation in use. I made a few modifications to it to shorten the length of the center hub and tap for a new grub screw (to bring the hand wheel closer in to the central pedestal), and also slightly shortened the existing shaft of the sander to accommodate it.
Another add-on I wanted to include was a brass drip-feed oiler. The sander's bearings are not sealed, and there was a small hole and simple oil cup present on the top of the bearing block to allow for occasional lubrication. An adjustable drip-feed oiler is absolute overkill, but I love the aesthetic, and it gives the machine a very early 20th century industrial look. I drilled out the oil hole in the pedestal, and tapped it to accept a lovely 100 year old Lunkenheimer "Pioneer" No. 0 brass oiler, which has a great scale proportion to the rest of the machine.
I knew I wanted to refresh the original chipping and damaged paint, and finally settled on a color combination of black and a reddish-brown. I further trimmed out the machine with new brass nuts and washers on stainless steel studs (including rubber shock-mount washers between the cast iron pedestal and base), and some brass washers I custom made to sit between the front and back of the bearing block and the attached handle and sanding wheel.
For some added flair, I made a wooden base from a plywood center section and some beautiful flamed maple quarter round molding I found amongst the usual trim at a local big-box hardware store. I used India ink to blacken the plywood, and French Polished the molding to give a warm antique look.
The last very important detail was the abrasive disc for the sander. As 8.5" is a fairly uncommon size for sanding discs, I bought some larger and readily available 12" sanding discs, and cut one out to fit the machine.
I could not be happier with how this machine turned out. It operates incredibly smoothly and sweetly, imparting excellent control and long "coasting time" after giving the wheel a spin. The aesthetics are exactly what I was hoping for: a machine that looks industrial but from another time
I know this sander will see a lot of use in my shop, and I look forward to putting it to work. I'd love to make another one, let me know if you're interested!