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Thread: Belt sander/linisher - good or bad?

  1. #21
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    The comments about power for small belt "grinders" is correct. But that just says the belt unit is not a substitute for a mill, really. It still has a lot of utility despite not being able to shape a piece of 1" thick steel in a few seconds like tundra twin track's big disc grinder.
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  2. #22
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    Quote Originally Posted by 3 Phase Lightbulb View Post
    I recently added a large(er) Jet 12" disc and 6x48" belt grinder to my machine shop, but was doing just fine with this small Delta Shopmaster SA180 unit with Zirconia belts. I used to use this grinder a lot in my 1st shop and I'll continue to use it for smaller items:

    I got that exact one. My biggest complaint was doing metal would wear out a belt fast. I recently tried some ceramic belts and they are much much better but still don't have a long life with steel. ALSO, I tried some of those scotchbrite type belts, they are great for many uses such as deburring and knocking off sharp edges, even removing tooling marks. STILL would like to find the holy grail belt type that really lasts.

  3. #23
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    Quote Originally Posted by Cenedd View Post
    Thanks BCRider. <<snip>>I might as well start from scratch. If I'm looking at motors and want variable speed and reverse, should I be looking at a three phase motor and small VFD or am I way overcomplicating things due to not having a clue?

    I went with a stick welder. Mainly because of the size and not needing a gas bottle if I'm honest. I'd like to claim some sort of purism relating to MIG being "too easy" and stick being closer to TIG....but it's all about the size...and cost. I did get a set of welding gloves, cheap auto-darkening helmet and spring hammer as well as upgraded cables and ends - the ones that came with it were somewhat anaemic....but you get what you pay for. I need to change the plug though as some design genius thought that the best way of making the fuse not blow at full power was to solder a solid bridge of wire under the 13A fuse (which is why it's no longer on sale!). I've already tested it on a (properly) fused extension so I know it doesn't blow in the ranges I'm likely to use - perhaps at full power (claimed to be 200A!) but I'd rather it was done properly! In terms of learning, I'll have you know that I've run ooh, at least six inches of weld bead on a flat plate....I'm practically a master! It'll do me good to have something I need to use it for rather than just being frustrated at not having the capability.
    First off, as a trades trained pipe welder, kudo's on selecting stick welding. It is the best way to learn to WELD except for gas welding, you could chose. It sounds very practical for your use as well.

    I built a 2X72 some years ago which is powered by a 3 HP 3 phase motor driven by a VFD... very handy.

    https://www.dropbox.com/s/o3zj9e1fayzudis/PICT0184.JPG?dl=0

    Those plans are available on the internet, and perhaps something like this scaled down for you size constraints might be fun to build. Considering that you will likely have greater availability of metric sizes, I was curious what metric sizes are commonly available to you? Even if you don't have room for the full 72 inches, a common size here, what sizes can you get? I guessing something around 1200 mm might be as small as practical. Longer belts are better. Even with shorter belts the belt speeds are important. Our friends, the knife makers who are very grinder centric, recommend 1000 to 7400 ft/min (300 to 2250 meters per minute).

    Here is another build that has a lot of views online:

    https://www.youtube.com/watch?v=a_RlL1O-bK4

    Good luck... the bad part is that having a grinder is really useful when yo are a novice welder :>)

    https://pics.me.me/mydad-says-using-...s-31997551.png
    paul
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    but you may have to

  4. #24
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    Quote Originally Posted by J Tiers View Post
    The comments about power for small belt "grinders" is correct. But that just says the belt unit is not a substitute for a mill, really. It still has a lot of utility despite not being able to shape a piece of 1" thick steel in a few seconds like tundra twin track's big disc grinder.
    Oh wasn't planning to use it in place of the mill. Mainly for relatively small adjustments when the mill setup takes more time than is justifyable and it doesn't need to be to 10 micron accuracy - because it's graduated to that, I find it hard to "Oh, that's close enough" if you see what I mean - and also for deburring, chamfering, finishing surfaces/edges and the like.

    Quote Originally Posted by ironmonger View Post
    First off, as a trades trained pipe welder, kudo's on selecting stick welding. It is the best way to learn to WELD except for gas welding, you could chose. It sounds very practical for your use as well.
    With no gas bottle and no spool, it's certainly space-saving. It's certainly a good price range to start off on even if I out-grow it.

    Quote Originally Posted by ironmonger View Post
    I built a 2X72 some years ago which is powered by a 3 HP 3 phase motor driven by a VFD... very handy.

    Those plans are available on the internet, and perhaps something like this scaled down for you size constraints might be fun to build. Considering that you will likely have greater availability of metric sizes, I was curious what metric sizes are commonly available to you? Even if you don't have room for the full 72 inches, a common size here, what sizes can you get? I guessing something around 1200 mm might be as small as practical. Longer belts are better. Even with shorter belts the belt speeds are important. Our friends, the knife makers who are very grinder centric, recommend 1000 to 7400 ft/min (300 to 2250 meters per minute).
    Looks good with interchangeable heads. I've had a quick look around and there doesn't appear to be the same almost everything is 2x72 that seems to be the case in the US. Widths from 1 to 6" or more but generally shorter lengths. I can find 50x785 (2x31 - at Axminster where I could walk in) and 50x1830 (2x72 - on eBay). Other suppliers seem to want to sell in bulk packs of all the same grit which isn't so helpful. Most other physical shops are wider and shorter so I'm guessing they're aimed more at hand-held belt sanders. Looking just at a ruler, 3" would be nice but I'm guessing that 2" is the popular size for reasons of power and just not needing that much width.

    Quote Originally Posted by ironmonger View Post
    Good luck... the bad part is that having a grinder is really useful when yo are a novice welder :>)
    https://pics.me.me/mydad-says-using-...s-31997551.png
    I'd already heard "Grinder and paint make me the welder I ain't" and I suspect that'll probably have a good ring of truth to it!

  5. #25
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    Quote Originally Posted by Cenedd View Post
    Oh wasn't planning to use it in place of the mill. Mainly for relatively small adjustments when the mill setup takes more time than is justifyable and it doesn't need to be to 10 micron accuracy - because it's graduated to that, I find it hard to "Oh, that's close enough" if you see what I mean - and also for deburring, chamfering, finishing surfaces/edges and the like.
    Yep, and handy it is for all that. I was pretty sure you "get it", some of the others seemed to think it's "go big or go home".
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  6. #26
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    Quote Originally Posted by J Tiers View Post
    Yep, and handy it is for all that. I was pretty sure you "get it", some of the others seemed to think it's "go big or go home".
    I'm more "Do it properly or don't bother doing it at all". Trouble is that sometimes just means I get nothing done.

  7. #27
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    Quote Originally Posted by Cenedd View Post
    I'm more "Do it properly or don't bother doing it at all". Trouble is that sometimes just means I get nothing done.
    Ther is nothing at all "improper" about a smaller belt/disc sander. They are good for a lot of things. Many of them things the big ones are less handy for.

    Pro-tip..... The disc is often more effective than the belt, especially when you are wanting to remove material quickly. It gives a rigid backing, and there is no "platen" to contribute friction.

    Put a coarser grit on the disc portion, it's easy to change belts, harder to change disc grit.
    1601

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    Hashim Khan

  8. #28
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    Quote Originally Posted by J Tiers View Post
    Ther is nothing at all "improper" about a smaller belt/disc sander.
    Sorry, crossed wires. Didn't mean that a disc was bad/worse; just if I'm going to buy one or build one, I want to be happy with the result.
    I liked the idea of the bayonet fixed quick-change buffing wheels. Might be worth seeing if that could be mounted either on one of the pulley wheels or driven off the motor in some other fashion.

  9. #29
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    On the welder, since it sounds like you need it to make a belt grinder. My own 3 way welder is still mostly used for stick. And I only use 3/32 stick at that. Yet I have no problem doing joints up to things like 3/4" round welded to 1/2" plate. It simply requires putting a really good "V" along the edge of the 1/2 and running three passes per side to get the proper cross section. And, here's the kicker, because I chose to use 3/32 rod to focus on the 1/8" wall tubing angle and 1/4" flat bar I mostly use for building stuff around here I'm only pulling around 100 amps from the welder.

    There's oodles of good videos on YT. Spend some time watching them all with special focus on the angle the rods are held at and the need to close the gap. Also note the position they guys use to support their arms in order to get a good flow as the rod gets shorter. Watching all that and then putting it into practice really helped me. I'm not much less green than you are. But after some time with it can make some welds that I'm proud of and which a decent pro welder would likely be OK with if on the back side where no one could see... My stuff typically doesn't look great by any means. But it doesn't fall apart either. My big success story was some large falling plate targets for the range. Obviously they get shot a LOT. Plus this big 20 lb plate of 3/8 steel falls onto a hunk of old tire every time. Yet the frames and base pins are holding up REALLY well after four years of this abuse.

    So there is hope for you. But welding is very much a practiced skill and art as much as it is a technical matter. All that angles and arc length and other stuff can be in your head. But it's a very fine mind to hand motor skill to get it right. And that means practice. LOTS of practice. When I lay the stuff aside for 6 to 10 months then need to weld something I make sure I burn off two or three sticks on some scrap just getting the hang of it back before I tackle the items I want to actually weld. Yes, it's easily that perishable a skill. So don't feel bad when you find you need to do something similar even after you get to where you think you're "good enough".

    OK, back to the topic. I see the guys above saying that they love their belt grinders and how even the small ones deserve respect. Well, yeah, they do. But simple math says that the area on a 1x30 inch belt is only 21% of the area of a 2x72 inch belt. So is it any wonder that the smaller belt machines wear the belts out quicker? That's the cost of a smaller belt.

    But you don't have the room for a 50 x 1830mm belt machine by the sounds of it. But try to figure out a smaller unit that uses the next size down. You want to come up with a solution that uses the LONGEST belt you can to maximize the are of abrasive surface. That'll give you the longest life. And by sticking with a 50mm width it also means you cut down on the surface friction from the backing platen. I see from one UK supplier that there's 50x1065 and 50x1525 as shorter options. I'll leave it to you to find the option that is more easily found and which comes in the widest variety and reasonable price.

    You're looking at the cost per total surface area and want to find the best bang for your pound on that front. The small belts to fit small machines need more joints per surface area and that's a big part of the cost. So keep that in mind too. Having said all that wider CAN be less costly too. But it's not as flexible for some uses. The 50mm wide belts are super easy to swap for grit sizes. The 100 and 150mm belts on the right machine are not bad but are never as slick to swap as the narrow ones. Keep that in mind for any flat table that wraps around the belt too. I love the idea of the side support. But the table with the notch to clear the belt and platten needs to be rapid retract and replace so it doesn't cause a big issue with belt changes.

    The bigger issue that has made me always go and lay down until the feeling goes away is that once you start down this home shop made belt grinder road but want to roll your own design for whatever reason to fit in with your own shop needs and restrictions it can become a jungle worth of options and it's hard to say "THAT ONE!" and send all the others away. Try not to be the ultimate perfectionist or it'll never get done.... ask me how I know

  10. #30
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    and the little belt grinder thst fits is much better than the big one that does not, or that you must build.

    I bought my Delta for about $60, hard to beat that for a machine you can be using a few minutes after you get it home.

    It will help you see if you really need a big one, and it will help you build it if you do.

    Get the belt plus disk type. The disk is really handy. You want it.

    Belts wear faster? Depends on the belt, but they also do not cost much in general. The better aggressive grits cut better and last longer, and cost more.
    1601

    Keep eye on ball.
    Hashim Khan

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