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Thickness Sander Design #1: Initial Thoughts

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Blog entry by depictureboy posted 07-18-2008 03:37 PM 5888 reads 3 times favorited 11 comments Add to Favorites Watch
no previous part Part 1 of Thickness Sander Design series Part 2: Initial Modifications »

I have been very impressed by the creativity and ingenuity of the users of this site. One of the best things I have found so far is the discussions on the thickness sanders. All the plans I have seen have been very nice, and very well done. However for my purposes I just don’t have the room for something that can’t be knocked down. So my goal with this project is to build a Thickness sander that can be knocked down, as well as still be a useful size for my projects and future endeavors.

One of the things I noticed is that most of the sanders seem to be for small parts sanding. Of course my perception of this could be wrong.

So my initial draft ideas are thus:
1. Primary importance is that the whole table be collapsible to some semblance of flatness and not be so heavy that it cannot be moved to its storage location.
2. The sanding drum would be rather large to give a good surface area availability
a. Maybe have the option of several drums with grits of different levels
3. The feed table must be wide enough to allow for most glued panels to fit.
4. The height between the table and the drum should allow the possibility for edge sanding ganged boards of typical thickness(2 to 4 inches)
5. Some sort of automatic feed system, using the same motor as the sanding drum if possible.
6. More options added as needed.

I started my initial sketches in Sketchup. Below is a rough draft of just the top assembly. I am currently working on the motor sub-assembly.

-- If you can't build it, code it. If you can't code it, build it. But always ALWAYS take a picture.



11 comments so far

View lew's profile

lew

11335 posts in 3216 days


#1 posted 07-18-2008 03:41 PM

Looks good so far!!

This is going to be my next project. Hope you don’t mind if I snag a few ideas.

Lew

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View GaryK's profile

GaryK

10262 posts in 3449 days


#2 posted 07-18-2008 03:45 PM

Some points on your points.

2. The bigger the drum (diameter and length) the bigger the motor you would need to power it.
3. You would need a very precision height adjustment for a second drum. Even the different thicknesses of grit would make a difference.
5. Any motor sharing wouldn’t work. Look at all the sanders on the market. They all have seperate motors.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View depictureboy's profile

depictureboy

420 posts in 3103 days


#3 posted 07-18-2008 03:53 PM

on point 3, I didnt mean at the same time. I would switch out the drums. Instead of having 2 pillow blocks, the side with the belt would be a U type thing( I have to research it). I could have 2 drums then, one for hogging and the other for fine finishing.

on point 2 I was looking at a 1hp, but maybe that wouldnt be enough, even with different sizing of the pulleys.

-- If you can't build it, code it. If you can't code it, build it. But always ALWAYS take a picture.

View GaryK's profile

GaryK

10262 posts in 3449 days


#4 posted 07-18-2008 03:59 PM

Here are the specs for my peformax 22/44 to give you an idea.

The motor is 1 3/4 HP
RPM is 1720
Direct connect to motor shaft 1:1 ratio
5” diameter Drum

Circumference = pi x diameter

3.1415×5 = 15.7075 inches

15.7075×1725 (RPM) / 12 = 2258 surface feet/min.

You could use a 2:1 pully with a 3450 RPM 1 HP motor
for about the same thing.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View depictureboy's profile

depictureboy

420 posts in 3103 days


#5 posted 07-18-2008 04:27 PM

Thanks Gary.

Math was never my strong point…Could you explain your calculation for me a bit more? I went to the pulley rpm site and given the numbers you suggested, the rpm on the drum would be 6900. That seems way fast to me. That would be with a powered diameter of 4 and driven diameter of 2. Do I have them reversed?

If I use a 1720 1hp with that configuration the rpms are 3440. Maybe I have my Powered to Drive ratio backwards.

-- If you can't build it, code it. If you can't code it, build it. But always ALWAYS take a picture.

View YorkshireStewart's profile

YorkshireStewart

1130 posts in 3362 days


#6 posted 07-18-2008 07:35 PM

You’ve no doubt studied my shop made sander: Click for details

My way of dealing with 2a, as you’ll see, is by using velcro backed abrasive. Grades can be changed in a matter of seconds.

-- Res severa verum gaudium - True pleasure is a serious business. http://www.folksy.com/shops/TreeGems

View GaryK's profile

GaryK

10262 posts in 3449 days


#7 posted 07-18-2008 08:30 PM

I think that you have to two pulleys reversed. The smaller pulley would go on the motor making one rev. of the motor equal to 1/2 rev of the drum.

1720 at 1:1 (direct drive with no gears or pulleys) means that the drum is rotating at 1720 rpm.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View depictureboy's profile

depictureboy

420 posts in 3103 days


#8 posted 07-18-2008 09:03 PM

Hey York, Yes yours is one of the ones I have studied. I was still going to use the velcro backed roller. I didnt realize a change was really that quick. Maybe i will just keep one roller.

Gary, In the mechanics of things is there any reason that I couldn’t use the same size pulley on each spindle? or even have the larger spindle on the drive shaft? I am sure it has some mechanical advantage having it the way you said, but I am curious as to reasons. thanks

-- If you can't build it, code it. If you can't code it, build it. But always ALWAYS take a picture.

View GaryK's profile

GaryK

10262 posts in 3449 days


#9 posted 07-18-2008 10:41 PM

You can put whatever size pulley you want where ever you want, but there are advantages and disadvantages to how you do it.

I only mentioned using a 2:1 pully on the 3450 RPM motor to slow it down and in effect would about double the HP at the drum.

You can use a 1:1 pully without a problem. I would just make sure that the motor you use has the HP and RPM you need.

You just need to determine how much performance you are looking for and use the motor/pulley combination to get it.

I provided you what my peformax uses to give you an idea what a commerical unit does.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View depictureboy's profile

depictureboy

420 posts in 3103 days


#10 posted 07-18-2008 10:56 PM

Thanks Gary, I hope I didn’t come across wrong.

I am trying to learn the right way to do things. I havent ever had to use pulleys and such, so I dont know alot about them. I dont want to make some fundamental mistake that could be seriously dangerous. I plan on using this for sanding(of course) but also thicknessing until I can afford a planer….

Thanks for your help.

-- If you can't build it, code it. If you can't code it, build it. But always ALWAYS take a picture.

View YorkshireStewart's profile

YorkshireStewart

1130 posts in 3362 days


#11 posted 07-18-2008 11:11 PM

Yes, I can change abrasive grades, including remove and re-fit the dust hood, in about sixty seconds

I did have a list of specs of a few commercial machines, but can’t find it just now. However, from memory, with a 5” dia drum, a speed of 1700rpm seems to be the standard. Gary’s lines up with that and that’s what I aimed for. I also used a 1.5 hp motor.

-- Res severa verum gaudium - True pleasure is a serious business. http://www.folksy.com/shops/TreeGems

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