Combine a 2x72 belt grinder & 9" disc ??

[rabler]

I've been fooling around with building a belt grinder, mostly muddling it over. Finally decided (New Years resolution) to use it as a project to teach myself FreeCad. I came up with the following idea, combining a belt grinder and disc sander. Maybe a boondoggle? Anyway, thoughts/comments from those who have built one before would be appreciated, on this and the general design issues. This is obviously not a polished design, but gets the proportions and general dimensions. Gas spring cylinder and some other basic hardware isn't shown. 9" disc. Base pivot with a 90 degree table turn on the belt grinder to give an edge sander.

 

[silence dogood]

A hundred years ago machines were belt driven by a common line shaft. There are a lot of combination belt and disk sanders on the market, But I have never seen one that used that type of belt sander. Go for it.

 

[keeena]

Many belt/disc combos I've seen have the disc direct-drive like your model...should work perfectly fine. I would support both sides of the table. One of my disc sanders has a support on 1 side only and it feels flimsy. Since the paper is adhesive it could be handy to make 3-4 discs for dedicated grits. If your sander is going to be VS (VFD): you might be able to use a diamond disc on it for slow speed honing carbide.

Speaking of: get a good brand of sandpaper. The cheapo no-name brands stick worse than a worn out post-it note.

That all said: I have 2 belt sanders have built-in disc sanders (8" and 12" IIRC) and I never (as in: ever) use the disc side. But YMMV.

 

[rabler]

I would support both sides of the table.

Problem is a back side support makes the grinder belt captive, so changing it gets messy

Yes, vfd on 2 HP motor. I wondered how useful the disc sander is for most people, your comment on not using it is hlpful.

 

[keeena]

Problem is a back side support makes the grinder belt captive, so changing it gets messy

Yes, vfd on 2 HP motor. I wondered how useful the disc sander is for most people, your comment on not using it is hlpful.

GP about the belt changes. Would a center support be possible in your design? Or a quickly removable table like some of the belt table designs?

 

[mikey]

I wondered how useful the disc sander is for most people, your comment on not using it is hlpful.

I had a disc on my belt sander and took it off. The disc was useful for wood but not so much for metal and it was a hassle to change the stick on paper if I needed a different grit. You also need a table in front of the disc for it to be useful. Personally, I wouldn't do it but that's me.

 

[mksj]

I do not think that the layout is a good combination unless it is has its own base. I think it would be a bit awkward to use with the disc so far back. That being the case, I have a small bench top unit that I use both the disc and belt and find it handy for small stuff, I plan to upgrade it to a bigger version. But for bigger projects and large metal shaping, I use a Jet J-4200 which is a 6x48 belt and a 12" disc. I almost always use the 12" disc sander as opposed to the belt. It has a good size table that is locked on both ends and very sturdy. The unit is free standing with the motor in the base so very easy to use either sanding unit. Getting good sanding discs/belts they last a long time, I use 60 grit on both. The disc and belt operate at different speeds, disc is primarily for metal.

I think in your case you might be better off with two separate sanders, a fixed speed larger disc sander and a dedicated variable speed for the 2" belt sander.

 

[Lo-Fi]

I guess my question would be: what can you do with the disk that you can't with the belt?
But it doesn't look like you're making big compromises to have the disk, so no harm giving it a go and seeing how you like it

 

[jwmay]

I wondered how useful the disc sander is for most people, your comment on not using it is hlpful.

Well then maybe not helpful that I use mine quite a bit. I haven't had a belt on mine more than 3 times in 3 years.
I'm guessing it has to do with what kind of work a person does. Mostly its a deburring station for me. I don't do any stock removal type work except at an actual grinding wheel. No knife making.
But more importantly, it looks like you're cruising right along with freeCAD! That would take me two weeks+ to get something remotely similar done with Fusion. AND my dimensions would be all wrong. Lol
Also..mine's just a 1x36 i think, with an 8" disc.

 

[Alcap]

I recently got a Foley 311 9” disc 1”x42” sander . I put a very course paper on the disc and finer grit for the belt . I find it helpful for me . I do think having a motor with shafts at either end would be better ( easier ) to build , maybe go with a 12” disc . Heres a picture form the internet of one like mine