Sanders?

[Janger]

Good to see what you have John Conroy.

Brian what rpm is that motor and what horse power? Do you want variable speed? Please post a picture of the metal flywheel pulley. Thanks!

 

[kevin.decelles]

Oooooo, I see a project forming. Very cool. I think I have everything but the skateboard wheels


Sent from my iPhone using Tapatalk

 

[Janger]

https://www.kmstools.com/king-industrial-3-x-79-metal-belt-sander-141967

Thoughts and questions on this style sander.

The drive train is just two 7.25" wheels with rubber tire treads. They have some to buy on amazon for about $50 each with the rubber tread. https://www.amazon.ca/Yibuy-Serrate...Y8VSH9QYN35&psc=1&refRID=SPQ8J99BJY8VSH9QYN35

On those sanders tension is from a two prong Y shaped axle holder inside the housing with an adjustment screw. It has a quick release so changing belts is simple. Tracking is a simple mechanism on the axle. The black adjust bar in the base lets you tilt the whole thing up/down. John C. pointed out the SFM of the machine is 6900 SFM which is really fast for a metal sander - probably too fast. Both the BB and the King are very similar units - must be the same people making both.

I like the fold out section on the top to get access to a large sanding surface. I'm imagining using it to rip the mill scale off larger flat bar so it's ready to machine. Flap discs on angle grinders do a quick job but they make such a mess and send grit everywhere in the shop. This flat sanding surface is similar to the Ellis machine @CalgaryPT has. Peter do you use your Ellis to rip off the mill scale or flatten large surfaces? Would a knife maker style 2x72 be as effective for cleaning up scale? What I'd really like is a tool simmilar to a two sider wood planer for metal. I know they have these things for industry but they're super expensive. Shove the metal in and it comes out cleaned up on both sides.

The tilt feature I'm not so sure about. It seems you would need to tilt it down to use it more knife maker style and then you're hunched over. Tilting it up means the belt is going up instead of down.??

 

[Chicken lights]

Why couldn’t you use an automotive style belt tensioner...to, well, tension the sanding belt?

Any that I’m used to seeing are spring loaded and require one tool, usually a ratchet, to release the tension so the belt can be changed

And unless the actual bearing is bad you could steal a used one from a wrecking yard, likely for next to nothing.

 

[PeterT]

Some of the knife belt sanders have accessories to grind down stock with the belt in lay down (horizontal) mode. But I think its kind of designed for blade guys on their typical stock who don't have mills. The stock retention & overall procedure look a bit iffy to me. There are also hand held belt sanders the autobody guys use but they are expensive, heavy when electric or air gobblers when pneumatic.
https://reederproducts.com/shop?ols...-grinder-c0db55d6-ad2d-44ce-a61f-980d82d3c2b2

https://www.google.com/search?q=pne...0LDkAhXeGTQIHTEkDYwQ_AUIESgB&biw=1920&bih=937

Grinding is a very power consuming & heat generating mode of material removal. The typical flap or disc sander mode for removing scale & crap is messy as you say but OTOH better to keep that stuff outside your shop full of precision machines if you are just prepping stock for milling. The neighbors may not like the noise or the red oxide dust cloud, modern life in the community I suppose.

 

[PeterT]

Here is another (blade application) vid of above that gives some visual context to material removal rate.

 

[Tom O]

I found this interesting.

 

[TheLocalDrunk]

I had a o at making my own 2 x 72 belt grinder. Works very well and fit well into my budget! I just couldn't justify the cost of the commercial units out there. I like the variety and cost of belts available.
I'm still making various tooling and accessories to go along with it

I really like that!
Might have to "borrow" that design.
If you were to make a second one.... what would you change?

 

[Janger]

Very interesting and informative videos! I’m quite interested in the mill scale removal question. Some guy has a demo of using muriatic acid - that’s strong stuff very fast. However somebody in the comments said vinegar works but is slower... well I have pickling vinegar 7%. I threw in some scrap and nuked it for 3 minutes. Two hours later look what happened.

It’s coming off all right with some wiping. I nuked it again as hot chemicals generally work better and I’ll leave it for a few more hours.

 

[Tom O]

This is the one at protospace using the caster wheels.

 

[PeterT]

The belt grinder performance video is interesting but there are a couple of apples & orange issues in there that could lead you to the wrong conclusion. You can't compare a wood sander to a metal sander regardless of belt width because the intended use materials dictate different SFPM values. Excessive speeds even with very coarse grit can cut inefficiently even to the point of burning wood whereas most ferrous alloys can tolerate & benefit by higher speeds. Its like comparing wood & metal band saws, except now the opposite applies - wood favors higher speeds because the tooth can make an efficient chip & remove it whereas metal has higher much strength & therefore limits to reduced SFPM for best efficiency.

Comparing HP alone is dangerous because its a function of rpm & torque. If you put a 1 HP 30Krpm spindle motor on, it would spin like crazy... until you touched the belt, then it would stall & fall off the efficiency curve. If you put a 1 HP 2Krpm motor on, it would never stall because it has so much torque, but you would never remove much material no matter how hard you pressed it in because SFPM is too slow.

 

[PeterT]

There are a whole bunch belt sander ideas & projects packaged in this home-made-tools link
https://www.homemadetools.net/category/belt-sanders-and-grinders

 

[Brian H]

I really like that!
Might have to "borrow" that design.
If you were to make a second one.... what would you change?

Actually, this is my second one. The first one I made was very crude an didn't have the ease of tracking and hydraulic cylinder for easy belt changes. I'm very happy with this design. I haven't come across anything I'd do differently

 

[Brian H]

The belt grinder performance video is interesting but there are a couple of apples & orange issues in there that could lead you to the wrong conclusion. You can't compare a wood sander to a metal sander regardless of belt width because the intended use materials dictate different SFPM values. Excessive speeds even with very coarse grit can cut inefficiently even to the point of burning wood whereas most ferrous alloys can tolerate & benefit by higher speeds. Its like comparing wood & metal band saws, except now the opposite applies - wood favors higher speeds because the tooth can make an efficient chip & remove it whereas metal has higher much strength & therefore limits to reduced SFPM for best efficiency.

Comparing HP alone is dangerous because its a function of rpm & torque. If you put a 1 HP 30Krpm spindle motor on, it would spin like crazy... until you touched the belt, then it would stall & fall off the efficiency curve. If you put a 1 HP 2Krpm motor on, it would never stall because it has so much torque, but you would never remove much material no matter how hard you pressed it in because SFPM is too slow.

I agree. When I do use my sander for knife scales I have to be very careful not to burn the wood. Key seems to be good sharp belts and keeping them clean.
Mine runs approx 3600 sfpm

 

[CalgaryPT]

https://www.kmstools.com/king-industrial-3-x-79-metal-belt-sander-141967

Peter do you use your Ellis to rip off the mill scale or flatten large surfaces? Would a knife maker style 2x72 be as effective for cleaning up scale?

I only use it for squaring surfaces. I did know of an artist that used your pickling vinegar trick but used a heated tank with a hose to a spray gun for large sheet products.

 

[Janger]

Very interesting and informative videos! I’m quite interested in the mill scale removal question. Some guy has a demo of using muriatic acid - that’s strong stuff very fast. However somebody in the comments said vinegar works but is slower... well I have pickling vinegar 7%. I threw in some scrap and nuked it for 3 minutes. Two hours later look what happened.

It’s coming off all right with some wiping. I nuked it again as hot chemicals generally work better and I’ll leave it for a few more hours.

After 24 hours the bright bits of metal are turning dull. But they clean up easily. On the right is after 30s on the sander. Middle is just steel wool. Left is raw stock with mill scale for comparison. The middle is kind of a uniform grey kind of cast iron looking. I think it would take paint well.

 

[John Conroy]

I added a 1" X 30" belt sander to the same stand as my large one. After replacing the supplied belt with a 240 grit one this is my go to sander for small stuff. Seems to be well built and very smooth with the higher quality belt. I cobbled together a platform for it from some sheet metal, thin angle steel and 1/4" round rod.

 

[Janger]

 

[Dabbler]

so if you *like* mechanical means, this video (a bit salesy) gives 2 alternatives of the 4:

 

[CalgaryPT]

so if you *like* mechanical means, this video (a bit salesy) gives 2 alternatives of the 4:

That was a great vid. Super informative. Too bad those brushes can be over 300 dollars.