Big DIY Belt Grinder Build (planning)
Posted: Sun Jul 07, 2019 2:53 am
I reached a point in the vice table build where I needed a belt grinder with flat table to do a nice job of what I was doing. Thought about asking a friend. Thought about buying one. Watched a load of YT vids. Remembered other YT vids that I had already watched. Saw some of the prices of new gear. And thought, I need to build one. I had previously discussed these with slackercam when over at his place one night, and that was what probably got me watching videos of them a while back, maybe 6 months ago or more. So I emailed the slacker and suggested a collaboration. No reply. SMS sent, he phoned me back, yep, keen to build 2 to some shared/agreed design. So I started thinking "what DO I want?" I was going to email him again, but thought I'd put it in public so others could add their 2c to the process, too. More eyes/minds = better, as evidenced in the vice table thread. :-)
The unit that inspired me months ago is called RM-48 Radius Master and is made in Australia. But it has a few minor issues: small table, small belt, 1.5kw/2hp, high price: $3400nz!! :-o
https://www.machineryhouse.co.nz/L096 and https://www.youtube.com/watch?v=OtuCsEyWVh8
It has a cousin with different features here: https://www.machineryhouse.co.nz/L0996
There are also some more reasonably priced (Chinese) and bigger belted units available like these: https://www.machineryhouse.co.nz/L120 under various brand names from various suppliers.
After that initial discussion months ago, some of the vids I watched include the epic fireball tools go kart belt grinder series:
And this somewhat annoying series with multiple attachments: https://www.youtube.com/watch?v=a_RlL1O-bK4
Another approach to reconfigurable belt grinders: https://www.youtube.com/watch?v=sXJx5CmcDuU
Lots of DIY contraptions out there, varying degrees of convenience/quality/etc.
Looking at the RM-48 unit with 1200 belt in triangle configuration, the triangle is approx 400 on each side. To do the same thing with a 2m belt would be approx 650mm on each side, bigger, but still reasonably compact, more so than the long style configurations.
Things I want out of the unit:
Any all thoughts/critique/ideas/contradictions/abuse welcome! :-)
The unit that inspired me months ago is called RM-48 Radius Master and is made in Australia. But it has a few minor issues: small table, small belt, 1.5kw/2hp, high price: $3400nz!! :-o
https://www.machineryhouse.co.nz/L096 and https://www.youtube.com/watch?v=OtuCsEyWVh8
It has a cousin with different features here: https://www.machineryhouse.co.nz/L0996
There are also some more reasonably priced (Chinese) and bigger belted units available like these: https://www.machineryhouse.co.nz/L120 under various brand names from various suppliers.
After that initial discussion months ago, some of the vids I watched include the epic fireball tools go kart belt grinder series:
- Part 1: https://www.youtube.com/watch?v=UXzoM-WXWRw
- Part 2: https://www.youtube.com/watch?v=pkoH1OfH-tw
- Part 3: https://www.youtube.com/watch?v=hM9Sr-d4Bvg
- Part 4: https://www.youtube.com/watch?v=3BPET6Y9x6A
- Part 5: https://www.youtube.com/watch?v=MEq-tMPJqXU
- Related: https://www.youtube.com/watch?v=HpKYYwpcWQM
- Tested 6: https://www.youtube.com/watch?v=wxjxZpB4zl0
And this somewhat annoying series with multiple attachments: https://www.youtube.com/watch?v=a_RlL1O-bK4
Another approach to reconfigurable belt grinders: https://www.youtube.com/watch?v=sXJx5CmcDuU
Lots of DIY contraptions out there, varying degrees of convenience/quality/etc.
Looking at the RM-48 unit with 1200 belt in triangle configuration, the triangle is approx 400 on each side. To do the same thing with a 2m belt would be approx 650mm on each side, bigger, but still reasonably compact, more so than the long style configurations.
Things I want out of the unit:
- Big belt, wide and long, long life and more versatile, 6" / 150mm by 2m are 90 for a pack of 3 in one grit from machineryhouse, didn't look elsewhere, this is cheap enough
- Long flat platen under the belt on one side, ideally about 500mm would be nice, but whatever works out with 2m belt + wheel radii is fine
- Easy/quick belt change for swapping out grits while working - open to design input here, haven't thought much about it except some sort of fulcrum point with one side near peak, other free
- Assembly counter weighted / balanced around pivot points / shafts for safe/easy reconfiguration of grinding style
- Spark collection/control is important for me in a very confined very flammable work area, well designed generous guards that collect and direct and control and deliver to a bucket of water perhaps
- Variety of wheel sizes from say 12mm up to 200mm or so including 100mm, 50mm, and 25mm or there abouts
- Belt tension works in any orientation, not purely motor weight/gravity
- Max single phase draw, so about 10-15A @ 240V, 2.4kw-3.6kw, 3hp to 4.5hp absolute max
- Three phase motor with VFD for speed control and soft start seems like a good idea
- Table very stiff/rigid/flat both in terms of the surface and the mounting setups
- Table adjustable distance to belt with small range, maybe fine thread adjusted?
- Table adjustable angle from 90 to 135 (45 down) with coarse/quick and fine/slow adjustments
- Table drilled on 50mm grid, for precision pins and precision angle setup using them
- Table pivot centreline exactly on the lip of the bevel ground table inner edge by way of placing hinges on ends outside belt area. (Unique idea?
- Platen position styles listed separately below:
- facing up for working above with downward pressure
- facing forward vertically with table below for normal use
- facing forward horizontally with table below for long parts
- away with large wheel forward for soft inside radii
- away with medium wheel forward for medium inside radii
- away with adjustable wheels forward for various tight inside radii
- away with one non-platen side facing forward (vertically)
- away with one non-platen side facing up
Any all thoughts/critique/ideas/contradictions/abuse welcome! :-)