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| Improved motorized dish sander http://luthiersforum.com/forum/viewtopic.php?f=10101&t=51545 |
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| Author: | doncaparker [ Sat Feb 02, 2019 12:21 pm ] |
| Post subject: | Improved motorized dish sander |
I thought I would share some photos of my rebuilt motorized dish sander. I’m tickled pink with the improvements I made. I’m looking forward to putting together some improved dished workboards to go with this gizmo. So, the motorized dish originally worked OK, but there was slop in the drive mechanism for the dish itself. The improvements (stolen 100% from others here on the OLF) fix that. Here are photos of the front and the top, to give you an idea of how it works: Attachment: Dish Sander from left.jpg Attachment: Dish Sander top.jpg The motor is a 1750 rpm motor I harvested from a cheap Harbor Freight belt/disk sander. I have mentioned before how this is a cheap way to get an electric motor. I also reused the pulley from that HF sander. The pulley attached to the motor is 1 5/8”. It drives a 4” pulley on shaft #1. That reduces the rotation to around 711 rpm on that shaft. Also on shaft #1 is a 1 ¾” pulley. It drives a 10” pulley on shaft #2. That reduces the rotation to around 124 rpm. I actually clocked it at 119 rpm. The shafts are both 5/8”, because that’s the size that fit the pulleys and drive plate I wanted to use. The shafts are secured by flanges with bearings of the right size. Here are photos of the inside: Attachment: Dish Sander front.jpg Attachment: Dish Sander inside front 2.jpg Attachment: Dish Sander inside front.jpg Attachment: Dish Sander inside back.jpg Shaft #2 drives what I call the drive plate. It is the aluminum disc from a 12” disc sander. I bought just the disc as a used spare part on eBay. Here are photos: Attachment: Dish Sander drive plate.jpg Attachment: Dish Sander drive plate closeup.jpg I have shaft #2 sticking up about a half inch to engage a slightly enlarged 5/8” hole in the center of the dished workboard. This ensures that the dish only rotates, and doesn’t wobble around, which my prior inferior drive mechanism allowed. The other pin sticking up is a router table starter pin that I bought from Rockler. It is smooth on top and has a ¼”-20 threaded mounting nub on the bottom. I drilled a hole in the drive plate about 1 inch in from the edge and secured the starter pin to the drive plate with a regular nut. This is the rotational drive pin. It engages another hole in the bottom of the dished workboard, 5" off center. The casters are just regular casters of a height and in a position that allows them to be sort of a failsafe to avoid tipping of the workboard under heavy load. The drive plate is 12” wide, so tipping probably won’t happen, but the casters make sure. Shaft #2 is strategically extended just the right amount to have the workboard bottom either slightly graze the casters or ride on them lightly. This is all meant to help avoid deflection of the workboard. I like thick workboards, so deflection is not a huge issue, but it is good to guard against problems. There are covers for the front and back of the box, so that fingers and other body parts don’t get tangled in the belts during use. This might sound like a lot of work, but compared to driving the bus a few times, I am happy to have this. Improved dust collection for this comes next. |
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| Author: | meddlingfool [ Sat Feb 02, 2019 1:30 pm ] |
| Post subject: | Re: Improved motorized dish sander |
I would like one of those one day... |
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| Author: | doncaparker [ Sat Feb 02, 2019 2:52 pm ] |
| Post subject: | Re: Improved motorized dish sander |
It's really not hard or expensive. I couldn't tell you how much in hard costs I have in it, but it can't be more than a few hundred bucks. It just takes a little time to tinker and put it together. |
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| Author: | Colin North [ Sat Feb 02, 2019 3:33 pm ] |
| Post subject: | Re: Improved motorized dish sander |
You know I used to think I really wanted one, but now I'm getting better at marking the sides on a radius dish and cutting to the lines (spoke shave/block plane) and it's only a minute or two on the abrasive in the dish to and a few minutes more for the back. Besides, can't swing a cat in the shop with stuff now 
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| Author: | fingerstyle1978 [ Sat Feb 02, 2019 4:08 pm ] |
| Post subject: | Re: Improved motorized dish sander |
Colin North wrote: You know I used to think I really wanted one, but now I'm getting better at marking the sides on a radius dish and cutting to the lines (spoke shave/block plane) and it's only a minute or two on the abrasive in the dish to and a few minutes more for the back. Besides, can't swing a cat in the shop with stuff now I'm in the same boat so I mounted mine on the wall ![[:Y:]](./images/smilies/smiley20.gif "Thumbs Up") I really need to get a better profile pattern for my sides though or something. What's your method? |
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| Author: | Colin North [ Sat Feb 02, 2019 4:11 pm ] |
| Post subject: | Re: Improved motorized dish sander |
fingerstyle1978 wrote: Colin North wrote: You know I used to think I really wanted one, but now I'm getting better at marking the sides on a radius dish and cutting to the lines (spoke shave/block plane) and it's only a minute or two on the abrasive in the dish to and a few minutes more for the back. Besides, can't swing a cat in the shop with stuff now I'm in the same boat so I mounted mine on the wall I really need to get a better profile pattern for my sides though or something. What's your method? I wish, no wall space either. |
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| Author: | meddlingfool [ Sat Feb 02, 2019 4:21 pm ] |
| Post subject: | Re: Improved motorized dish sander |
Joey, there's a tut around here somewhere for that but I'll try to explain it, or at least what I do... I take cardstock from the dollar and a half store and make a piece 5.5"x 32". Then I line the inside of the mold of whatever body template I'm making, with one edge of the cardstock aligned with the edge of the mold. Then place the mold in the radius dish, find a big fender washer, and roll it around the mold with a pencil in the low aspect of the center hole tracing a line on the cardstock. Mark waist and end points and voila. Gets a very accurate profile which pretty much matches the dish exactly after bending, save lot of time. Sorry for the derail... |
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| Author: | fingerstyle1978 [ Sat Feb 02, 2019 5:07 pm ] |
| Post subject: | Re: Improved motorized dish sander |
meddlingfool wrote: Joey, there's a tut around here somewhere for that but I'll try to explain it, or at least what I do... I take cardstock from the dollar and a half store and make a piece 5.5"x 32". Then I line the inside of the mold of whatever body template I'm making, with one edge of the cardstock aligned with the edge of the mold. Then place the mold in the radius dish, find a big fender washer, and roll it around the mold with a pencil in the low aspect of the center hole tracing a line on the cardstock. Mark waist and end points and voila. Gets a very accurate profile which pretty much matches the dish exactly after bending, save lot of time. Sorry for the derail... Thanks, I've been going about it all wrong lol. Seems pretty simple now that I think about it. I guess I'm a dumb#$%!!! |
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| Author: | meddlingfool [ Sat Feb 02, 2019 5:42 pm ] |
| Post subject: | Re: Improved motorized dish sander |
Often the obvious is only so after someone else points it out. I didn't figure it out myself, that's for sure... |
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| Author: | J De Rocher [ Sat Feb 02, 2019 7:25 pm ] |
| Post subject: | Re: Improved motorized dish sander |
I do a variation on the method Ed uses. I run blue painters tape along the inside of one half of the body mold sitting in the radius dish and then scribe the profile on the tape with a pencil in a small wood block (I'm going to steal Ed's idea of using a fender washer for the next time. Should have thought of that). I then transfer the tape to a 32" long piece of poster board that's pre-marked for the body depths at the neck and tail ends. I then cut the profile along the scribed line on the tape. The side profiles I've gotten this way are very close to the final profile and take very little time in the sanding dish. Attachment: Making side template profile 1.jpg Attachment: Making side template profile 2.jpg
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| Author: | fingerstyle1978 [ Sat Feb 02, 2019 7:38 pm ] |
| Post subject: | Re: Improved motorized dish sander |
How did Torres eve figure all this s&*$ out with no power and no internet? Lol |
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| Author: | meddlingfool [ Sat Feb 02, 2019 7:39 pm ] |
| Post subject: | Re: Improved motorized dish sander |
No ideas in that were mine, they're from someone else's tut... |
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| Author: | J De Rocher [ Sat Feb 02, 2019 7:54 pm ] |
| Post subject: | Re: Improved motorized dish sander |
Don - That's a cool design. With it sitting on the bench, what's the height from the benchtop to the upper surface of the radius dish? |
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| Author: | doncaparker [ Sat Feb 02, 2019 8:19 pm ] |
| Post subject: | Re: Improved motorized dish sander |
Thanks, Jay! I don't use it on the bench, because it is not super portable (kinda heavy and a bit bulky), and it would sit too high for me during use. I only had it out on my bench for working on it. The dish sander normally lives on top of a homemade plywood storage cabinet that's about 19" tall. The dish sander box is 14" tall, and the top of the drive plate sticks up about 2 3/4". If you figure a dished workboard of about 1 1/4" thick, that would put the top of the dished workboard about 18" from the bottom of the dish sander's box. With my setup, that puts the top of the dish at 37" off the floor. If a person wanted the working surface to be at about benchtop level, she/he would have to do something similar to what I have done: Put it on a lower platform. The motor and the shafts need about a foot of vertical space inside the box. |
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| Author: | James Orr [ Tue Aug 20, 2019 11:36 pm ] |
| Post subject: | Re: Improved motorized dish sander |
This is great. Thanks for sharing, Don. |
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| Author: | doncaparker [ Wed Aug 21, 2019 5:40 am ] |
| Post subject: | Re: Improved motorized dish sander |
My pleasure, James. As an update, I mentioned improved dust collection as my next goal for this homemade machine. I later built a set of easily removable walls (about a half foot tall) that create an octagonal box around the top of the sander, with one of the eight walls being a rectangular HVAC vent that feeds into my dust collector. Even with a ClearVue, it doesn’t capture all the nuisance dust until I brush it toward the intake, but I’m hoping that it does a good job of capturing the tiny stuff before it gets too far. I wear a fine dust respirator during sanding, just to be sure. This arrangement doesn’t interfere with normal operation of the sander, and it keeps the nuisance dust inside the box for later cleanup, so I’m happy with it. It’s hard to imagine a dust collection method that would catch everything with a machine like this. Added bonus, however: I later realized that, with this octagonal box, I was 90% toward building a downdraft table. I just cut a piece of plywood to fit the top of the octagon, drilled a bunch of 3/4” holes in the plywood, and set it on top of the octagon. It seems to work OK! A dedicated downdraft table would be more efficient, and I still use a respirator, but it was worth the very small amount of extra effort, given what I had already built. I could post a few pics if anyone is interested. |
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| Author: | Clay S. [ Wed Aug 21, 2019 6:27 am ] |
| Post subject: | Re: Improved motorized dish sander |
For those with limited space, appropriating something from the kitchen might work. It has three speeds and is compact and portable. You can still use it to mash potatoes (even while sanding if you don't mind high fiber). I've made two motorized dishes - the other used a bowling ball balancer. Both were cobbled together in just a few minutes by mounting a dish on an existing mechanism. |
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| Author: | James Orr [ Wed Aug 21, 2019 10:47 pm ] |
| Post subject: | Re: Improved motorized dish sander |
doncaparker wrote: I wear a fine dust respirator during sanding, just to be sure. I’m wearing one if I’m doing ANYTHING that makes dust (as opposed to shavings). I don’t have the allergic reaction some do, I just hate feeling gunked up. And I use my netti pot after. Sent from my iPhone using Tapatalk |
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| Author: | Ernie Kleinman [ Thu Aug 22, 2019 6:53 am ] |
| Post subject: | Re: Improved motorized dish sander |
Don quick question, what is the sizing on those wheels ? are they also hf ?? thanks |
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| Author: | doncaparker [ Thu Aug 22, 2019 7:10 am ] |
| Post subject: | Re: Improved motorized dish sander |
Ernie— I think I bought the casters on eBay. They are 2 3/4” tall, which probably means they are 2” diameter wheels. I am pretty sure you can buy similar casters at Harbor Freight. They have lots of sizes when I go in there. I think I remember considering smaller casters, but they felt too small and flimsy for the task. You have to consider how high up off the platform you want the drive plate to sit. Recall that I needed to give shaft #2 (photos above) a booster seat inside the box in order to get that shaft to stick up a few inches from the platform. I think buying all the hardware is the first step, and then you can cut the wood to work with the hardware. And, of course, all your shafts, pulleys, bearings and belts have to be coordinated. |
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