I will try to show you my latest project.
There are vids on YouTube which show more, the best I have found is by Dave Gatton, look him up.
Now, here we go.
Step 1: Find What You Can, or Just Ask Around!
Hi all. This is my first Instructibles. I didn't intend to ever post one, but I have been encouraged by others to do so. I have watched Instructibles for ages and love it (apart from the often terrible spelling, that is). You are all so creative and amazing, well done.
This Instructibles was initially inspired by others, who can be found on this site, who have created a drum sander from a treadmill and other parts.
I needed a drum sander and this was the cheapest and most fun way of getting one. It also turned out to be my most eclectic build to date.
Firstly, it is made from.......wait for it,
* a discarded electric treadmill
* a set of French Doors, found in hard waste rubbish and rescued from being taken to the tip
* timber from a single bed, collected with the Frech Doors
* scraps I have in my workshop, including several hinges, chipboard (also rescued!), threaded rod, Velcro, electrical connectors etc.
Step one is to get the treadmill, and the timber for the frame.
Framing will vary according to the treadmill dimensions etc. French Doors were perfect!
Step 2: Disassemble and Create Frame
I apologize that there are not many pics here. It was never intended to be seen, as I said before, so I didn't keep a record of the process very well.
Once I had the treadmill I disassembled it and made sure I put a chalk arrow on the motor so I knew which way is would spin. You will need to do this so you mount the motor on the correct side so the drum spins towards you at the sanding face.
If you spin the drum the wrong way the timber will fly out the back, you need to push against the drum rotation. Important.
You can see from the pic that the bed of the sander is a cut down portion of the walker, nice and slippery.
Step 3: The Drum Construction.
As per other people's instructibles, I used my router with the circle cutter to cut lots of 150mm diameter circles. I then used a holesaw to cut the correct size hole for the centres, using a drill press. Fortunately the holesaw was the correct size for the spindle I had.
Each treadmill will have two rollers, but obviously the one with the pulley attached was the right one for me.
You may need to see which is the strongest and best suited for your particular treadmill.
I slid all the chipboard onto the roller using plain old Aquadhere as glue. There is lots of surface contact, so that was fine and seems to handle any pressure to date, (would have preferred MDF, but I wanted to do it all from what I gathered, as much as possible).
Step 4: Frame and Bed
I saw the French doors had bracing in just the right places, so I cut them into two sections each. See pic.
Part of the bed frame I collected became the legs on the bottom.
The smaller section of the doors are the top frame, where I attached my roller and drum, the longer section are the uprights.
Bits of timber was used to strengthen and set the width of the frame. Sorry, not many pics, as I said. Videos coming in other steps, hang in!
Now, the bed.
It is part of the walking surface of the treadmill. At the far side I have attached it with three of the larger hinges I had, for lateral stability. Works well.
Step 5: Lifting Mechanism
Ok, this part took me some time to nut out actually, in the next step you can see my first version of the lifter, the threaded rod in the centre version.
Lots of people use a threaded rod under the centre of thefront of the bed to raise and lower it.
I did that. You can see a hole through the top of the front piece of timber under the bed if you look closely. That's where it used to be.
I also put a piece of the treadmill under the bed to ensure it was a rigid as possible.
Unfortunately it had a fair bit of lateral flex, would have been ok, but I wanted better.
So, after many a dreaming night, I devised the two half circle device you see in the pic. Remember, the older version is in the next step.
I put a piece of melamine under where I wanted the lifter to go, it's the white board in the pic.
I cut a circle from chipboard approx 150mm diameter and then cut a smaller radius inside that, giving me a ring of chipboard.
I then measured as best I was able the distance between the melamine and the table.
I cut the ring into two matching sections.
I put some more bed frame between the sections, having to bevel the edge to match the curve of the chipboard, to strengthen the lifting frame.
I then attached two hi he's on the top of the lifter, which attached to the table.
I cut out a section on the lifter at the bottom and put a hinge there, which I had welded a nut to for the threaded rod to go through.
You need to ensure that the hinge move a little and the threaded rod clears the lifter because the lifter changes attitude to the front of the sander.
Ok, I will put the worst drawing I have ever done here to explain it perhaps a little easier. See pic.
Step 6: Motor and Wiring
I had to buy a new fan belt from a motor spares shop, cost $35:00 AUD.
The one that was with the treadmill was very short. Take the belt to your shop and they will match the profile.
To get the correct length, just measure from the top of the pulley on the drum and down to as far as you think is ok to mount the motor later. The blokes at the shop will get it, and provide you with a few alternatives. Keep your receipt, just in case!
Ce I had the be,t, I placed it on the drum pulley and then hang the motor from it, noted the position and mounted the motor.
Now, the weight of the motor is enough for me, and others, so that I don't need to pull it down with a spring etc. Will most likely be the same for you.
My motor was already in a metal tray affair, so I just put some bed frame timber across the side and a screw to hold it in place. I also bent a piece of aluminum to a L shape and screwed it over the tray so that it would not bounce off the screw, and makes it easy to remove if I need to.
I also put a length of chain (I had all this, I build marimbas!) on the motor pulley side, a bit longer than needed, just in case the fan belt broke, so the motor won't fall and also bend the plate it is on.
Step 7: Running the Drum
Sounds ominous. Running the Drum.
You can see my improved lifter in this video below.
I put Velcro on the slider section, to make it smoother. Not needed, just nice!
I was worried when I turned it on for the first time, that the drum would be so out of true that it would vibrate too much to be able to work on it, but it was actually great.
The video is before I trued up the drum, quite smooth really.
To true it up, I first built a very rough dust hood, cut a hole in the top for my vacuum to attach to and then glued some 40 grit sandpaper to more of cuts of chipboard.
I had to rebate the sides of the board to allow it to pass over the aluminum sides of the table.
Once this was dry, I then progressively raised the table and sanded the drum true. In step three you can see one of the boards I made to sand with.
I then sprayed it with lots of varnish to seal the board. This will help when I put the sandpaper on the drum.
Step 8: Sandpaper
I have only found one supplier of hook-and-loop sandpaper.
Search for 'The Sandpaper Man' in Australia. I have placed an order for a few grits and 115mm wide. I worked out that I will need about 1.5m to spiral around the drum.
I had some Velcro already from a hardware store to put onto the drum, but it is very narrow.
The sandpaper man in Australia sells some that is 305mm wide, I will need about 700mm to spiral around my drum.
To get a good spiral, there are YouTube vids out there which explain how to determine the correct measurement you will need BUT I have since discovered (since putting this instructable up) that they seem to have it wrong.
The best I have come across is by Dave Gatton, but he shows that the shape will be a trapezoid. If you look at my last video you will see that it is actually a parallelogram.
Search for him and you will see lots of what I have explained here. He is great, and builds neater dust hoods as well! I just didn't care what mine looked like. Make sure you get some paper or plastic and make a mock-up before ordering or cutting the real thing.
Step 9: Cutting the Velcro for the Drum
you can see from the video that the plastic template I used is cut as a parallelogram, not trapezoidal, as per the YouTube videos.
I spoke with the supplier and questioned this, he had never heard of cutting any other way apart from what you see in the video.
The pic is of the drum, which I have now sander lots, sealed with varnish, sanded again, filled with putty, sanded, primed, sanded and primed again.
It is nice and sealed, and smooth enough for the application of the Velcro when it arrives next week.
I will add a step to show this later.