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Thickness Sander Concept for the ShopSmith Crowd

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Forum topic by shipwright posted 03-21-2011 09:42 AM 3942 views 0 times favorited 16 replies Add to Favorites Watch
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shipwright

5309 posts in 1546 days


03-21-2011 09:42 AM

Something to ponder:

1) SS (500 and later anyway) comes with two outputs on the left side that run at two different speeds.
2) Drum sanders (thickness type) need two drives at different speeds.
3) I could use a drum sander for veneer leveling here in AZ.

So could the output speeds be reconciled to the required drive speeds for a drum sander without resorting to ten foot diameter pulleys?
Well, yes actually.

The following concept shows my idea for such a beast. I think if my calculations are correct (Please check them. It’s late and I could be miles off) the feed belt would run at about ten feet / minute and the drum would run at about 1700 rpm with the SS set at 700 rpm. If I’m right, this concept could work well….........maybe.

This is only a concept at this stage. Something to think about and give me feedback. The sprocket and chain are imported and not very true to scale and lots of things like covers, bearings, dust collection and structural bracing are omitted because I’m very new at sketch up and it’s a lot of work for me.

So… Am I nuts? or am I onto something? or do I need those ten foot pulleys because I can’t do simple arithmetic?

Thanks in advance for your comments and ideas.

Paul

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/


16 replies so far

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sras

3939 posts in 1878 days


#1 posted 03-21-2011 05:16 PM

I think you might be on to something. (might what to clean up the original post – got duplicate chunks of text in there) I have been pondering a ShopSmith mounted belt sander for some time, but had not considered the possiblity of driving the feed belt as well – makes perfect sense!

Do both shafts rotate in the same direction? I have had my SS for nearly 30 years and have never checked!

From what I understand, the 1700 drum speed of the top shaft is exactly what you would want.

10 feet per minute is 2 inches per second – might be OK, but personally I would prefer a little slower. Need to check the specs on commercial sanders. At 700 rpm, you must be using a set of pulleys to reduce the speed. A 10 fpm belt running on 2 inch diameter rollers would be spinning at about 19 rpm (6.28 inch circumference means ~19 revolutions to feed 120 inches). That means you need a 37 to 1 reduction for the belt drive. A pretty big reduction, but there are several ways to do that. I bet you could accept a reduction as high as 40 or 50 to one and I think the speed would be OK.

-- Steve - Impatience is Expensive

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shipwright

5309 posts in 1546 days


#2 posted 03-21-2011 07:14 PM

OK all fixed.

As for the speed ratios, they are as follows:
SS output, top shaft = 700 rpm, 1.5” to 9” ratio= idler shaft speed of 11.67 rpm, 1.5” to 9” again = 19.44 output shaft rpm. two inch drum at 19.44 rpm = 6.28” circumference x 19.44 rpm = 122” / minute = 10.17 feet/minute.
I did get the pulleys reversed on the drum drive but I fixed it this morning. They are now:
SS lower output at 700rpm upper output = 1141 rpm, 4.5” to 3” ratio = output speed of 1711 rpm.

Yes Sras, in the same rotation.

You should be able to click on the sketch up and download it for fill examination.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

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sras

3939 posts in 1878 days


#3 posted 03-21-2011 07:57 PM

Yep, that should work. Couple of other thoughts…

Have you considered adding a surface sanding platform to the top side of the drum?

Might want to extend or shift the belt such that the drum is centered on the belt platform. Not sure if that is a big deal, but seems like a good idea…

-- Steve - Impatience is Expensive

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shipwright

5309 posts in 1546 days


#4 posted 03-21-2011 08:11 PM

#1, No I haven’t got that far yet, but it’s an easy option to add. #2, Extend maybe, but the reason it’s off center is that it runs directly off the lower output which is of course on center. I didn’t want to have to put an extra idler shaft on that side just to center the drum.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

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rance

4147 posts in 1909 days


#5 posted 03-21-2011 08:28 PM

Clever design for sure. Nice drawing too, although I’d prefer you use more components. :) I think you are coming right along with your SU talents. I didn’t run the numbers but fitting it to your SS is really clever. Have you thought about a cover for the drum?

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

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shipwright

5309 posts in 1546 days


#6 posted 03-21-2011 08:32 PM

Thanks Rance, As I said in the initial post, this is concept stage, lots of details missing. I did make every part a component. Can I lose components by doing things while a component is open?

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

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rance

4147 posts in 1909 days


#7 posted 03-22-2011 04:29 AM

Maybe you had one component open while adding separate pieces. What do you see if you go to your link and do the download yourself? I’ve heard of models reverting to their basic form, but for the life of me, I don’t recall what causes it. Could it be something to do with publishing to 3D warehouse?

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View steviep's profile

steviep

232 posts in 1395 days


#8 posted 08-29-2011 09:33 PM

Hey Paul,

Have you done anything with this lately? Really intrigued by the concept.

-- StevieP ~ Micheal Tompkins - you were not here on earth long but left a giant mark on us. RIP Brother

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shipwright

5309 posts in 1546 days


#9 posted 08-30-2011 02:19 AM

Not a thing at all but I’m off to AZ in November where my shop is all SS and doesn’t have a drum sander so I may get at it then. I still like the concept.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

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steviep

232 posts in 1395 days


#10 posted 08-30-2011 04:36 PM

Love the concept. Was planning on building a thickness sander anyway. You mind if I tinker with your idea?

-- StevieP ~ Micheal Tompkins - you were not here on earth long but left a giant mark on us. RIP Brother

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shipwright

5309 posts in 1546 days


#11 posted 08-30-2011 04:59 PM

Not at all.
The parameters that I set for myself were that it had to be easily adjustable, relatively cheap and make use of the two power outputs on the Mark V to operate the drum and feed. It would take all the fun out of it if you used an external feed motor for example.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

View Bertha's profile

Bertha

12951 posts in 1442 days


#12 posted 08-30-2011 05:15 PM

I don’t own a ShopSmith but I tend to support anything ShopSmith. If you’re arithmetic isn’t wrong, perhaps the pulleys could be windmill operated in a power outage;)

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

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Billp

784 posts in 2948 days


#13 posted 08-31-2011 06:45 AM

Paul when it comes to gear reduction Steven Mines (LJ) really knows his stuff. He redesigined his duplicating Lathe and added all kinds of drives to it. I think its a harpo lathe. The company even paid him a wad to take a look at what he had done. I have been to his shop very impressive and he’s a great person.

-- Billp

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steviep

232 posts in 1395 days


#14 posted 08-31-2011 03:52 PM

I was tinkering with this last night and need some help from those of you that have Thickness Sanders in your shop. I need to know how deep does the opening need to be. I am assuming the most common use for this would be panels and doors I can see a acoustic guitar body maybe? The first thought I have is Why not attach the sanding drum directly to the final drive, but this will severely limit the size of the input depth. What do you guys find yourselves using you sanders for?

-- StevieP ~ Micheal Tompkins - you were not here on earth long but left a giant mark on us. RIP Brother

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shipwright

5309 posts in 1546 days


#15 posted 08-31-2011 05:23 PM

You’d get a lot more readers if you posted this question as a forum topic. Here you will only get people who find this very old thread.
That said, I have a big dual drum sander here in my BC shop and I honestly can’t even tell you how wide it opens without looking. Probably six or eight inches, maybe more. The fact is that I almost never use it at more than a couple of inches, usually under an inch.
There’s a photo of one on the SS forum that runs off the main drive and uses a hand crank to advance the belt.
You should join that forum anyway if you have a SS.
http://www.shopsmith.net/forums/showthread.htm?t=6256

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

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