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shopmade sander steel shaft
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Author:  Dennis Leahy [ Mon Oct 31, 2005 12:14 pm ]
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I'm planning to build a shopmade drum sander. I want to buy the shaft material before I buy the pillow block bearings. Precision ground shaft material (1-1/4" diameter for the drum, and 1" diameter for the feed rollers) will cost me about $100. But, I see that I can get a six-foot length of 1 1/4" dia. steel round from a couple of places for about $25. Do I need to buy precision ground shaft for this, or will the rod work just as well?

Thanks,

Dennis
Author:  Dennis Leahy [ Mon Oct 31, 2005 1:51 pm ]
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Hi Michael,

I've seen a few pictures of shop-made units, and only because I don't want to fork out $170 plus shipping for a drum from Grizzly, I plan on making a 6" drum, using MDF circles/donuts epoxied to an 1-1/4" steel shaft. Once the unit is built, I will reverse-sand the drum, that is, I will place an immobilized board covered with sandpaper on the bed, and raise the bed until it contacts the raw wood drum. Once the drum is "trued", I plan to use hook and loop over the MDF, and hook and loop sandpaper spiral wrapped around that.

One guy I know that made one strongly recommended that the shaft for the sanding drum be at least 1" in diameter. 1-1/4" diameter is only about $10 more: cheap insurance.

For the motorized feed rollers (which will spin much more slowly than the drum shaft), I figured 1" diameter steel shaft would be plenty thick. I'll cover that with 120 grit sandpaper (no hook and loop) for grip. The only reason I can see to upgrade the feed rollers to 1-1/4" diameter is because I can get three 24" lengths out of a 6-footer. Even with the added expense from larger pillow blocks for the feed rollers, the overall price may be lower if I can get three shafts from one 6-footer (especially if steel rod rather than precision ground shaft will work.) If I am shooting myself in the foot by purchasing round rod rather than paying the extra for the precision grinding... well, I don' want to do that. This sander will cost me about $400 in parts, (including a 2HP motor and a 1/3HP motor), and I hope/expect it will provide the capabilities of an $800 - $1200 sander.

I should mention that with 24" length shaft stock, I plan to have about 20" width sanding surface.

I'd love to see photos of your sander, and anyone else that has one they could show. I'm pretty close to finishing up plans for mine, but I will scrap my plans and start over if I see ideas I didn't think of (or didn't already steal.)

Dennis
Author:  tippie53 [ Mon Oct 31, 2005 1:54 pm ]
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If you are making a thickness sander this will be too small. As for a drum sander like in 3 to 6 inch verticle I would use rubber so you can expand it.
   Shafting though strong enough will not make a very good sander. This is why drum sanders ( verticle ) are usually rubber on a 3/4 shaft and thickness sanders are about 6 inches in diameter on pillow blocks. Get a machinist handbook and it can help explain the different alloys and what will work best for your configuration. Different steels are desinged for different jobs. Too hard and it can break and too soft it can dent and deform.
      The heat you will generate on a 1.250 shaft will pull resins out and clog very fast. Good luck on your build and I wish you well.
john hall
Author:  Dennis Leahy [ Mon Oct 31, 2005 1:58 pm ]
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Hi John,

I'm sorry I didn't post enough info in my original post, and it looked as if I planned to make a tiny (and very hard!) 1-1/4" drum. As you can see by my next post, it will be a 6" wood drum. I'm only trying to figure out if I need to spend the extra money on a precision ground shaft to go inside the MDF.

Dennis

{edit} Thought I'd add a picture of what I'm considering doing for the MDF. Supposedly, several people who have built drum sanders with wood drums have had them go out-of-round, or develop high spots, after a while in use. That makes me think the heat is building up in some areas of the drum, and the drum has no way to easily dissipate the heat. So, I have a hunch that if I do something like this (maybe with the help of my local CNC guys):


...that the drum will be able to dissipate heat better. (The small hole would be used with a 3/16" wood dowel, during glue-up, to keep the voids lined up. I might want to add 2 more, forming an equilateral triangle - for balance.)

I'm also guessing MDF will more likely be balanced than a drum made of plywood (even Baltic Birch).DennisLeahy38656.9421180556
Author:  Anthony Z [ Mon Oct 31, 2005 3:41 pm ]
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Michael I am not to keen on truing up your drum as you suggest particularly if the infeed table isn't perfectly flush with the drum. You could end up with a drum that has a slight taper in diameter which isn't optimal. You can make your infeed table adjustable to flush with the drum.

Dennis that sounds like quite the design for a DIY Drum Sander if your design includes a power infeed table.

For what its worth I build my own and purchased a General International 25" long, 5-inch diameter drum together with their bearings and bearing caps. It cost me about USD$200 to 250 for the General parts. No worries about heat build up or a drum that doesn't stay true.   Just my 2 cents. Have you had a look in the MIMF library -- there are a bunch of archived discussions on home made Thickness Sanders.
Author:  old man [ Mon Oct 31, 2005 4:38 pm ]
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Mine has only been in operation for about 6 months, but so far it works very well. I used a 5/8" steel rod from Lowes, 24" long, took it to a machine shop and had a keyway cut in it. My drum is solid wood. I split a 4" by 4" (actual size) piece of white pine down the middle, routed half of a 5/8" circle down the center of each, then glued it back together. Turned it round on my lathe, inserted the rod then drilled two holes through one side of the drum, through the shaft and about 1 1/2" into the other side. Then drove a 16d nail through it, countersunk and filled the hole with epoxy. I trued it up as Michael said, covered the drum with velcro material and use velcro backed sandpaper rolls.

Ron
Author:  CarltonM [ Mon Oct 31, 2005 4:56 pm ]
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Seems like you could avoid the problem of having the drum too out of parallel before you true it up, by leveling the table true to the bare SHAFT, before mounting the wood/MDF. Sound reasonable? I've never built anything like that, so I could be missing something important (yeah, I know...like my mind!).
Author:  Dennis Leahy [ Mon Oct 31, 2005 11:04 pm ]
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[QUOTE=old man] I used a 5/8" steel rod from Lowes, 24" long, took it to a machine shop and had a keyway cut in it. Ron[/QUOTE]
Wow, If you had success with a 5/8" diameter rod for the drum shaft, then my idea of going with 1-1/4" sounds like overkill. And, it sounds like steel rod, rather than a precision ground shaft made from steel worked for you as well.

Dennis
Author:  Dennis Leahy [ Mon Oct 31, 2005 11:18 pm ]
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[QUOTE=CarltonM] Seems like you could avoid the problem of having the drum too out of parallel before you true it up, by leveling the table true to the bare SHAFT, before mounting the wood/MDF. [/QUOTE]
I had figured that I would make the parts for the sander's sides, as well as the adjustable table/bed's (angled) sides using the same router templates, to try to make them uniform. And, I will build it upside-down on the bench, to use the top edge for alignment reference. I don't think I can get the adjustable table to raise high enough to contact the bare shaft, but I like the way you're thinking, and a couple of 3" idiot sticks should allow me to find the ideal mounting height for the table/bed's angled ramps.

Dennis
Author:  Jimmie D [ Tue Nov 01, 2005 3:51 am ]
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Dennis,
I used 3/4" cold rolled rod on mine with a piece of 5" aluminum pipe for a drum. The shaft seems to be OK.
Author:  TomS [ Tue Nov 01, 2005 3:52 am ]
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I happen to have choosen 1.25" TGP shaft (turned, ground and polished cold drawn shaft) for my drum sander too because it seems about right to me. The only problem with using hot rolled shafting is it is not always perfectly true or straight. Also the steel is a little softer and not as good for key seats or mounting bearings. Also I am mounting my drum using taperlock bushings so I want a precision shaft surface. I'm surprised by the $100 dollar figure you quoted for your ground shafting, that seems high to me. I work in a machine shop, and our over-the-counter price for 1.25" TGP shaft is about $8.20 a foot, and 1" TGP is about half that. This would be a type of material typically used for machine shafting.
Author:  Daniel M [ Tue Nov 01, 2005 6:34 am ]
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Dennis;
If you're going to use "idiot sticks" to set your table adjusting geometry, don't forget to subtract half the diameter of the shaft from the stick length...
Sometimes the obvious gets lost in the details! Just hoping to prevent a "DOH!" moment.
Good luck with your project. Can't wait to see some pics!!!
Dan'l
Author:  crazymanmichael [ Tue Nov 01, 2005 7:22 pm ]
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i used go kart axles for my feed rollers and mdf disks, with a gear motor from ebay for the power.

i had heard that mdf will overheat and go plastic and distort if used hard at higher rotational speeds in a sanding drum. i avoided the need to worry when i found one of the performax radial arm saw units(with radial arm saw)at auction for $60. crazymanmichael38658.141400463
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