2" X 42" Belt Grinder

[Mork]

I made this belt grinder with two 1/2"x 6"x 6" printing press shims (to level the press). I chucked one of the pieces in my 4-jaw and cut the hole then turned the pulleys on my Logan 200. The crowns were cut by setting the compound at 1.5 degrees cutting to the center, flipped the piece and did the same (V shaped crown). The belt tracks perfect and 1.5 HP is plenty. 80-grit is great for hogging off tons of steel, 120 is good for general deburing and shaping and 800 grit is amazing for sharpening knives and chisels!

Link has more pictures and videos

https://onedrive.live.com/redir?res...30&authkey=!AFxCzARorkHfL90&ithint=folder,mp4

 

[mikey]

Nice and clean - great job, Mork!!

 

[rwm]

I love the simplicity and compactness of that design. No tracking adjustment? What are the pulley diameters?
R

 

[TommyD]

Nice work

 

[kvt]

That looks good, simple but effective. Thanks

 

[Mork]

The pulley diameters are 3" for the drive and 2" for the idler. I used a similar grinder (at work) as a model in some respects but the one at work is 1725 PPM. My motor is 3450. The one at work had a 4" pulley so the belt surface speed is 50% faster on mine. I'm sure their are advantages to slower speeds, like less heat but, I'm glad I made mine faster. Most often I just want to shape metal or deburr and if I want to sharpen I can limit contact time to reduce heat. Honestly, if I was to make another one I'd go a little faster... this little sander runs circles around the Baldor at work!

As far as tracking goes... I think I got lucky and everything is well aligned. As a test I took an adjustable wrench and put twisting pressure on the tension arm and it made the belt miss track.

One great aspect is cost. The 1-inch grinder at work sells for nearly $500 and mine cost me about $35.

 

[rwm]

Thanks for the details. Especially the speed information. I'll see what motors I have. Any issues with slippage on the metal pulleys?
I am thining I could align the top pulley by laying a weld bead on one side of the vertical support as necessary. Once it's aligned it should stay that way yes?
R

 

[mikey]

I think you can still buy the parts that Sears uses on their 2 X 42 belt sanders from Sears Parts Direct. You might look at the tracking mechanism on their sander as its quite good and very precise. Tracking will vary from belt to belt so some way to adjust tracking is necessary. Oftentimes, you need to track the belt off to one side or the other to grind a step into a part so adjustable tracking is really nice to have. A really solid platen, ideally with a Pyroceram liner on it, and a precisely adjustable tool rest are other must-haves, I think.

Again, nice job.

 

[Mork]

RWM, I have had no problem at all with slippage. I was somewhat concerned about this when I build the grinder but at least so far it's not an issue. I think more crown on the pulley would create more slippage (less contact area). I think I mentioned this about but the crown I used was 1.5 degrees. I can't say if less would be better but this worked very well.

I put a set screw just under the top lever pivot point but ended up removing it. This seems a bit crude but it there is a problem its very effective. The belt pulling pulling down on the upper pulley will try to deflect it downward and the set screw would remove any slop in the pivot point and compensate.

Here's a theory I have based on working in the printing industry for many years. We have all kinds of belts ranging from about 18 inches wide doe 1/2" inch wide. The wider the belt the more difficult it is to keep it tracking right. 2 to 3 inch Also a larger crown works better to a point but tends to cup the belt.

So to answer your question, Yes I suspect that once the tracking is adjusted it should stay put unless something wears. I have a 4 inch belt sander for woodworking and it seems I have to tweak the tracking fairly often... again, this is over that 3 inch width and with a shallow crown.

Mikey, thats a great idea to buy the pulleys but it was actually fun to make the pulleys. Also, the motor I was working with had a strange end in the shaft. It had a threaded shaft... this may or may not be an issue if you buy the pulleys.

 

[rwm]

Thank you. Makes sense.
In my motor stock I have a Baldor 3/4 HP 1725 motor. What say ye?
R