2x72 belt grinder build

How are you going to cut those parts? Plasma? laser? waterjet? Angle grinder?
I had thought about sending them out to be laser cut (sendcutsend.com). I got the large plate design to upload but I had actually already welded it together (before facing it). With a projected cost of $140, I decided to go ahead and just mill what I had. I tried several times (literally redrawing them from scratch in CAD) to get the two smaller pieces to upload but sendcutsend kept rejecting the DXF files that Freecad produced.

I may try again on uploading for the dark green bracket that holds the platen and front rollers, it has several arcs. But that'll be a bit before I get to that.
 
Working on the dark blue base, making the supports for the arms. These are 2" x .75" x 6.5" cold rolled 1018. I want the upper arm to fit into a bit of a taper so that it seats well. I picked 5 degrees per side, but I don't have gauge blocks to use with a sine table. I suppose I could mill something close enough to the needed thickness, but the reality is that as long as the arm and the sides match, the angle doesn't have to be precise. So I went ahead and milled the upper arm at the same time. This will also help with welding as I can just clamp it all together.

My mill doesn't have front/back adjustment (nod?), just left/right (tilt?). This meant a bit of messing around to get the pieces set up right. My table travel is only about 8" in the Y axis. But the whole head can be cranked in/out. As a side note, I'm thinking of adding a cheap 1 axis DRO, even a repurposed caliper, on that in/out so that I can calibrate moves. The challenge is that the arm is 14" long, and has to be turned outward to do one side and inward to do the other to get angles on both sides using the same left/right tilt of the head.

I also went ahead and relieved the bottom of the V. This offsets the platten base a bit from the table arm so that the platten pivot action doesn't interfere with the table arm. As a side note, I really like this glacern face mill, 3", high positive rake, I'm using ISCAR SEHT43AFN IC28 inserts. Only real problem is that is showers chips in about a 6' radius around the mill. :)

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Wow! Great project. Great documentation. I built one last year, very similar to what you are doing. I also started with FreeCAD but am so slow at learning CAD that I went back to pencil and paper, weld and grind, trial and error. ;)

Mine is powered by a treadmill motor and is variable speed. It also goes horizontal. I cast the wheels from aluminum, then installed the bearings. I am still not super happy with the tracking wheel adjustment. It works great but hard to move. I think the spring is hanging up. Otherwise, it was a fun project that included many of my interests, from casting to welding to machining. And lots and lots of head scratching! I would have liked to have the skills to draw it up ahead of time but that is a project in itself.

What are you doing for wheels?

Good luck! Cheers!
 

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@ShawnR,
Yes, drawing it up in FreeCad was quite a task, but I'm now comfortable enough with FreeCad basics to use it for other things so I'll count that as success, even if I'm still not proficient. I'm going to use a 2HP AC motor with a VFD. Casting is not (at least yet) in my skill set. The smaller wheels I will turn out of some 3" aluminum stock, the larger drive wheel I have a short piece of aluminum 1/2" wall pipe 6" OD, and am looking at welding in 5" disc to make the center that will bolt to a steel hub. Design drawings from FreeCad below.
 

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@ShawnR,
Yes, drawing it up in FreeCad was quite a task, but I'm now comfortable enough with FreeCad basics to use it for other things so I'll count that as success, even if I'm still not proficient. I'm going to use a 2HP AC motor with a VFD. Casting is not (at least yet) in my skill set. The smaller wheels I will turn out of some 3" aluminum stock, the larger drive wheel I have a short piece of aluminum 1/2" wall pipe 6" OD, and am looking at welding in 5" disc to make the center that will bolt to a steel hub. Design drawings from FreeCad below.
Your contribution and documentation for this project is a valuable addition to the forum.
I don’t enjoy your confidence or ability with any form of CAD but many do.
Thanks for sharing
Lots if pics please.
 
@Janderso
Pics incoming!
Here's welding the supports for the arms to the motor base. First I opened the plug weld holes up to 3/4" most of the way through, left the 3/8" hole at the bottom. I clamped up the arms and the support brackets to the base to get a good fit, and then welded. Not delighted with this weld job. I welded these with my MIG box, I should have used the TIG so I could back off on the power near the top and fill them without undercutting. I did a rough milling pass to clean up the welds. I guess a bit of auto body putty and it will look great :oops:

Last picture is one of the pivot arms clamped into place, welding both of those in will be next but I want to set up a spacer rod to keep them parallel.

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@ShawnR,
Yes, drawing it up in FreeCad was quite a task, but I'm now comfortable enough with FreeCad basics to use it for other things so I'll count that as success, even if I'm still not proficient. I'm going to use a 2HP AC motor with a VFD. Casting is not (at least yet) in my skill set. The smaller wheels I will turn out of some 3" aluminum stock, the larger drive wheel I have a short piece of aluminum 1/2" wall pipe 6" OD, and am looking at welding in 5" disc to make the center that will bolt to a steel hub. Design drawings from FreeCad below.

I am still working on 1 piece drawings in FreeCAD. I was just getting to the point learning assemblies last year when I got distracted, and, well, tried to do a basic drawing the other day and had to go back to tutorials to get started again.

Your drive wheel will be like mine, sort of. The treadmill motor had a heavy flywheel on it. I got a piece of 6 pipe as you did, and and bored it and turned it as best I could. I then turned the flywheel down to, a "large" press fit, I mean, more than normal. I read somewhere that the pipe will expand a lot with heat. It was winter here so the flywheel went into the snow bank and the torches hit the pipe. I think the difference was like 10 thou. I put a couple of pieces of 3/4" tool bits into the center of the pipe and, literally, dropped the flywheel in. Actually, did it twice. The first time, it landed crooked. I was lucky to get it out. Second time went well. The whole operation on the lathe was kind of iffy, due to the size of my chuck but I was very very careful and went slow.

The wheel is sized, sort of so that the tach displays half of the surface speed. If I added a second magnet, the tach would be surface speed but I can usually handle x2 (usually..;-) ) And really, after using it, actual speeds are general anyways. It can go too fast.

If you are interested, the build is here.
 
Your drive wheel will be like mine, sort of. The treadmill motor had a heavy flywheel on it. I got a piece of 6 pipe as you did, and and bored it and turned it as best I could. I then turned the flywheel down to, a "large" press fit, I mean, more than normal. I read somewhere that the pipe will expand a lot with heat. It was winter here so the flywheel went into the snow bank and the torches hit the pipe. I think the difference was like 10 thou. I put a couple of pieces of 3/4" tool bits into the center of the pipe and, literally, dropped the flywheel in. Actually, did it twice. The first time, it landed crooked. I was lucky to get it out. Second time went well. The whole operation on the lathe was kind of iffy, due to the size of my chuck but I was very very careful and went slow.
Hadn't really thought about press fit, but not an option for me at this point as I have the material for the weld up. My TIG welder only hits 210 amps, and with a 1/2" thick tube wall plus a 1" thick center, I doubt the TIG welder will put out enough heat to properly weld that. I was looking at aluminum brazing with aluminum/zinc rod, but a fellow member from here offered to let me try his MIG spool gun.

Anyway, need to finish the motor base and pivot-base pieces first.
 
Got the pivot arms welded on.
First picture shows the detail of how the arm that holds the front platen and rollers is tapered to fit in. It will get slotted for a clamp bolt and other details, so it is barely more than rough stock (2"x2" CRS). That makes a heavy/solid arm. I'm thinking I could have extended the pivot arm up a bit to act as a hard stop, but the taper is only milled into that arm enough for it to go that far back anyway. The square tube is a piece of scrap that is proxy for the arm that holds the table, although that will also be a piece of square tube. The second picture shows more or less the whole assembly so far, fresh from welding and still warm.
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Trying to create the mounting piece for the disc table.
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Plan was to weld up 4 pieces into a square tube with an inside surface of 2" square. So a cut some pieces of hot rolled, milled the inside face. Then I clamped them up to a 2" square tube and welded. Didn't want to penetrate to deeply to avoid welding it to the inside tube.

The first attempt failed as after I welded it I went to clean it up on the mill my welds were way too shallow. If you open the thumbnail below you can see the seem opened up on the piece on the right. I milled up some more pieces, beveled and gapped the welds a bit, and went a bit hotter on the MIG. More pics when I get it cleaned up.
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