2x72 grinder discussion

[TorontoBuilder]

I assume your talking about 'jer schmidt'? ive looked at his videos, to me, it looks like the thickest section on his belt grinder is maybe 1/2". I also dont see a grinder he has built using a c-face motor, so he is not loosing any shaft length for the plate.

i would measure the wheels you have/get, measure the shaft, and make sure that using 5/8 isnt going to give you problems with shaft/bore engagement before you order it up

I checked already, I only need to chnage up a few fasteners. The 3D model vandelay sells is just prefect for planning modifications

 

[Dan Dubeau]

Here's the difference between the two places for my motor plate. Exact same user interface....Although Cutmyparts has thickness options up to 1" whereas Readysetcut only goes up to 1/2". Interesting, and noted. If I didn't already have the plate, I'd probably send it out and have done. IMO $55 is a pretty cheap way to buy a couple hours of time. On the other hand, I like making stuff, and can use the round slug for my built up drive wheel flange, so I'll get two birds stoned at once, and machine them all at one before splitting. Just a WAG, but I bet the rest of my parts would probably come in around $200 or under. Not a bad way to save some time again, but a little here, a little there and it all adds up. Time saved is time saved, but cash out of my wallet is always a driving factor. I pick and choose my battles......On this one, I chose to buy all my wheels for both the fixed platten, and contact wheel. The only one I'm making is the drive wheel, and the reason why will reveal itself later. I'll probably make my small wheels at a later point. Can't see buying those, as a lot of the options are pretty spendy, and I don't really like the designs.

When I was playing around last time, I did notice that had some pretty significant price breaks for multiple quantities. I didn't get into loading a bunch of different profiles to test one off/vs same, but I'd bet there would be if they're all cut from the same plate. If I get some time tomorrow I'll play around loading the rest of my profiles, and see how the #'s change and shake out. Who knows I may end up pulling a 180, and just buying them after all....

 

[Dan Dubeau]

I assume your talking about 'jer schmidt'? ive looked at his videos, to me, it looks like the thickest section on his belt grinder is maybe 1/2". I also dont see a grinder he has built using a c-face motor, so he is not loosing any shaft length for the plate.

i would measure the wheels you have/get, measure the shaft, and make sure that using 5/8 isnt going to give you problems with shaft/bore engagement before you order it up

I crossed that bridge (design wise anyway) with mine when I switched to a c face mount. IMO It's a valid concern. One that depends on motor shaft l/d, and wheel type. For mine, I'm starting with 1/2" plate, that will probably clean up around 0.45" which is more than plenty for my design. I was also going to machine down the plate where the motor mounts, to 3/8" to gain an extra 1/8" stickout on the motor shaft though. That will leave me with a theoretical 1-5/8" shaft stickout past the plate, but since I'm making a built up wheel, with a "weld on hub" (1.5" long), that will sit flush with the end of the motor shaft and give me 1/8" clearance to plate. It all works in cad.....;D

 

[ShawnR]

I built one a few years ago. Thread here. Like it a lot and use it almost daily. Regrets though are only that the treadmill motor I used is one of the smaller ones available. The controller is not ideal for this application as it is easy to bog down, and it used to blow fuses. I installed a circuit breaker and learned to cut lighter with it. I have been meaning to look at motor upgrades. But the speed control works well. Cost was minimal. I made the wheels from cast aluminum and pressed in bearings. The drive wheel was the original belt wheel from the treadmill which I turned down to fit into a piece of 6" black pipe, friction fit it and put the requisite concave surface on it. I wanted a "lathe/welding/use up stock project" so I did not mind the lathe work. I guess I bought bearings, the pressure cylinder for belt tension, and tach. I had most of the steel in stock. The design is a combination of a couple I found on line. I probably quoted them in the thread. I think I learned a lot from the project and ended up with a great tool. Rewarding project for me. Can't ask for much more I suppose.

Mostly finished photo in post #132 but only half the image is showing when I click it. And I have added a spark shield so will take better photos today.

 

[Dan Dubeau]

I made a couple changes again last night to my main flat platten attachment that were bothering me like making it rotate to 45* instead of just 30*, plus I swapped a 2" Al wheel for a 4" (100mm) rubber contact wheel as the bottom roller, and was up till 12:30, and since 6 this morning for a couple hours fixing all the cascading problems that caused with the other components (that circled part below was a bit of a pita figuring out belt clearance again......). It's a slightly more complicated platten design (reduced part count by two, but increased complexity) to machine/build than what I had, but IMO will be a much smoother/cleaner design and better tool to operate, which is the ultimate end goal. I also made a lot of progress with the surface grinding attachment, but there's still a few important details to figure out at a later point (like height adjustment screw design and packaging), but I'm confident that building the rest of the actual grinder won't cause me any issues with that part. I've always been a big fan of iteration by CAD, because it's much easier with an undo button, than a welder and angle grinder. But man, somebody hurry up and take this laptop away from me, and kick me out to the shop already......

I've lost track of how many iterations of just the flat platten arm I've gone through at this point, I'd guess about 10-15?, but I'm not even counting the ones that never made it out of Neuro CAD. From a simple flat plate, to tubes, to interchangeable wheel sizes, and a couple more ideas I came up with and had to work my way through in CAD. I'm pretty happy with this version, and think it will accomplish a lot of what I want it to do on this one arm. All the other "extras" can be future tool arm attachments.......But this one will probably carry 80% of the load as the daily driver. I didn't want to have 10 different tool arms taking up space, so I tried to make them all multipurpose....There is still one annoyance with this version in that when I rotate the platten up to 45* I wanted the 100mm roller to come up to the pivot point so the center would be the same in both rotations like my all my other contact/small wheel attachments. As it stands It's about 0.4" short, but making it come up that 0.4" to center causes a big pile of more belt clearance and hinge issues, so I will live with it.....I did play out what I need to do to make it happen (that was a long detour), but the other issues it causes just weren't worth the trouble, and I'd lose platten length which is more important for me. It really won't make one lick of operational difference in the end, but I know it'll bug me.....

Anyway.....I'm pretty sure I'm good to start machining a bunch more stuff at this point. I think all the major decisions have been made and proven to work at this point so I don't think I'll have anything but minor variances I can solve on the fly at this point. Sad part is, I probably won't get a chance to make chips until next week now . And I still have to make a tooling plate so I can mill all the flat 2d profiled parts......Well, I don't have to, but I want to because I have a good idea for one.....

 

[David]

View attachment 58869

Here's the difference between the two places for my motor plate. Exact same user interface....Although Cutmyparts has thickness options up to 1" whereas Readysetcut only goes up to 1/2". Interesting, and noted. If I didn't already have the plate, I'd probably send it out and have done. IMO $55 is a pretty cheap way to buy a couple hours of time. On the other hand, I like making stuff, and can use the round slug for my built up drive wheel flange, so I'll get two birds stoned at once, and machine them all at one before splitting. Just a WAG, but I bet the rest of my parts would probably come in around $200 or under. Not a bad way to save some time again, but a little here, a little there and it all adds up. Time saved is time saved, but cash out of my wallet is always a driving factor. I pick and choose my battles......On this one, I chose to buy all my wheels for both the fixed platten, and contact wheel. The only one I'm making is the drive wheel, and the reason why will reveal itself later. I'll probably make my small wheels at a later point. Can't see buying those, as a lot of the options are pretty spendy, and I don't really like the designs.

When I was playing around last time, I did notice that had some pretty significant price breaks for multiple quantities. I didn't get into loading a bunch of different profiles to test one off/vs same, but I'd bet there would be if they're all cut from the same plate. If I get some time tomorrow I'll play around loading the rest of my profiles, and see how the #'s change and shake out. Who knows I may end up pulling a 180, and just buying them after all....

That's a big price difference for one part.

 

[Dan Dubeau]

That's a big price difference for one part.

If I were to take a guess, based on the available thickness' from each, They probably have a much bigger payment on that laser than cutmyparts does......