New tilting 2x42

I had to make a second trip up to Bellingham today because Grizzly sent me a false notification the other day that mine was in. 😂

They had their variable speed 1" x 30" grinder on sale, so I actually snagged one of those too, lol. I figure the 2" x 72" Reeder will stay in the shop full time for knives. The Grizzly 2" x 48" will be used outside oriented horizontal to square wood blocks with a jig I designed. The Grizzly 1" x 30" will be used outside to pretty up phenolic scales for displaying at shows. Some of that really old stuff has substrates in it I'd prefer to keep away from the shop, so I think having a designated grinder for it will be nice. :)

I'll try to get it set up this weekend so I can post a video. I have the Reeder partially pulled apart to wire more tools to the VFD, so I'll try to get a video comparing the size of the Central Machinery (Harbor Freight) 1" x 30" vs the Grizzly 1" x 30" vs the Grizzly 2" x 48" vs the Reeder 2" x 72" (I still owe you a video of that too REK Knives REK Knives ).

On that note, if anyone in the Olympia/Lacey/Tumwater/Tacoma area of Washington state, I have a Central Machinery 4" x 36" and a 1" x 30" that you can have.
 
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Thom Moss said:
So mine arrived weds. It's cool but at 25lbs not expecting much. It would be wicked easy to change it to 1x1 tooling arms with a little time. The small idler and tracking wheels get scorching hot after running for just a few mins (not grinding just running it full speed 6000rpm trying to get it to track better. Tinkered with it a bit yesterday. Hopefully pictures work, but have some on my insta (mossknives) built a new platen with 2" and 4" rubber wheels. removed the drive wheel and aligned all wheels out a bit, away from frame this am, not shown in video. I Think tracking wheel will be next to go and using a 3" I have around.

https://photos.app.goo.gl/P7dGs5TyGJNVDYmb9


https://photos.app.goo.gl/4H7pA7UdG6Jq9HPS6
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Thats awesome man! Would you say you could possibly
Thom Moss said:
So mine arrived weds. It's cool but at 25lbs not expecting much. It would be wicked easy to change it to 1x1 tooling arms with a little time. The small idler and tracking wheels get scorching hot after running for just a few mins (not grinding just running it full speed 6000rpm trying to get it to track better. Tinkered with it a bit yesterday. Hopefully pictures work, but have some on my insta (mossknives) built a new platen with 2" and 4" rubber wheels. removed the drive wheel and aligned all wheels out a bit, away from frame this am, not shown in video. I Think tracking wheel will be next to go and using a 3" I have around.

https://photos.app.goo.gl/P7dGs5TyGJNVDYmb9


https://photos.app.goo.gl/4H7pA7UdG6Jq9HPS6
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That is awesome man! Do you think you can make a 6 or 8 inch contact wheel work with a 2x48 belt for doing hollow grinds?
 
I did the rough grinding on 3 knives today using 2x48 belts, it works fine for rough in. After the first 1 added the washers like J J Lensmire after the second I pulled the drive wheel and moved it like Thom Moss Thom Moss and decided I need to order a 3" tracking wheel so he also validated my thoughts on that. I was going free hand cause I haven't welded up a bigger workrest yet. I am pissed at the platen but haven't decided what to do about it yet. I like the one posted but I don't have equipment to make the one he made. All in all it's 100* better than my multitool 2x48
 
My desire to slow the belt speed down would require a 3" diameter drive wheel - That might hold the belt from slipping enough since lots of pressure wouldn't normally be used with this grinder. Calculating from the 5" drive wheel it looks like the motor rpm is around 1500 to 5000 rpm based on the spec'd belt speeds. A 3" drive wheel would help giving a belt speed range of around 1100 SFPM to 3900 SFPM. While not what I'd like, still better than the stock spec'd speed range.
 
Ken H> said:
My desire to slow the belt speed down would require a 3" diameter drive wheel - That might hold the belt from slipping enough since lots of pressure wouldn't normally be used with this grinder. Calculating from the 5" drive wheel it looks like the motor rpm is around 1500 to 5000 rpm based on the spec'd belt speeds. A 3" drive wheel would help giving a belt speed range of around 1100 SFPM to 3900 SFPM. While not what I'd like, still better than the stock spec'd speed range.
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Earlier in the thread J J Lensmire put in the calculations and the specs appear to be incorrect. The machine does around 600 to 6500 fpm. I kinda suck at the grinder and at lvl 1 I even turned it up. That thing is slow at the first speed. I'm not sure what you would do with it. Maybe shape plastic so it doesn't melt?
 
The belt speed numbers came from a calculator on Burr Kings website. Don’t think it should matter if belt is 2x72 or 2x42. I just know that the grinder goes below 1000 rpm so SFPM is lower then a lot of numbers thrown around
 
I have a hi torque DC motor (spare for mini mill CNC project). That is 2500rpm that I might experiment with after I see how this runs for a few months. But fitted a 12" wheel, (barely fits) and my small wheel holder last night to try to find out what this will be used for in the shop.
 
If the motor will go <1,000 rpm that's good. AT 1,000 RPM with a 5" drive wheel gives around 1300 SFPM belt speed. It it goes down to 600 rpm motor speed then it's only around 785 SFPM belt speed. That's a good speed. Those 1000 SFPM speed ranges are really good for working wood scales. My 2X72 runs from around 350 SFPM to 5,000 SFPM belt speeds and I use it from low to high.

Yes, 2X42 or 2X72 the drive wheel and motor RPM is what controls the belt speeds. I was only going by the Grizzly spec sheet for belt speeds. Sounds like the spec sheet might have the low speed wrong?

I'd love to know how the control the motor speed. It says in the Q&A the motor is a "3/4 HP, 110V, single-phase, 7.8A Motor." 1 ph motors don't normally have a very good speed control.

Thank ya'll for the info provided

Later
 
Ken H> said:
If the motor will go <1,000 rpm that's good. AT 1,000 RPM with a 5" drive wheel gives around 1300 SFPM belt speed. It it goes down to 600 rpm motor speed then it's only around 785 SFPM belt speed. That's a good speed. Those 1000 SFPM speed ranges are really good for working wood scales. My 2X72 runs from around 350 SFPM to 5,000 SFPM belt speeds and I use it from low to high.

Yes, 2X42 or 2X72 the drive wheel and motor RPM is what controls the belt speeds. I was only going by the Grizzly spec sheet for belt speeds. Sounds like the spec sheet might have the low speed wrong?

I'd love to know how the control the motor speed. It says in the Q&A the motor is a "3/4 HP, 110V, single-phase, 7.8A Motor." 1 ph motors don't normally have a very good speed control.

Thank ya'll for the info provided

Later
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It's either a stepper motor or a servo motor that doesn't have the reverse function. Someone way smarter than me may be able to dig around in the controller and find out that you can put in a switch and actually have reverse but that's just me thinking out loud. No idea if that's true or not.

I didn't note any power loss at lower rpms like with my variable speed 8" grinder. The grinder obviously loses torque at low speed this one reversenot so much. I have a 8" contact wheel coming for it I didn't wanna chance a 10 but Thom Moss Thom Moss said he got a 12 to fit so that's pretty sweet. Servomotorkit.com has motors that would def fit that have reverse function and much more hp but that's hopefully a long time in the future. I didn't notice the motor really getting hot or struggling like the grinder.

Edit- I was looking around at some hobby forums on how to reverse polarity on a stepper motors and I saw more than one post about how a stepper motor can create more power than its controller actually generates when hand turned and can kill the controller. Maybe spinning it fast by hand to check tracking isn't the best idea.
 
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You reverse stepper (or servo) motors by the controller wiring, not on the motor itself. You're right, steppers and servo motors have just as much torque, or perhaps a tad more at low RPM as they do at max RPM. Nope, rotating a stepper motor by hand with the power turned OFF does no damage. It will generate a bit of voltage and might cause some LEDs to light up a bit.
 
What's the difference between a stepper motor and a dc motor?
 
REK Knives said:
What's the difference between a stepper motor and a dc motor?
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This is the best version I can find for reasonable explanation without getting in the weeds.


The main thing it looks like is to understand how a stepper motor works differently than a dc motor and then just think of a dc motor with a planetary gear set as a servo motor. I'm sure that is wrong. But that's the way my brain is seeing it. Stepper motors are just dc motors with more triggers. I think. It's awfully late on a UGA football Saturday night to be answering questions like this.
 
Ken H> said:
You reverse stepper (or servo) motors by the controller wiring, not on the motor itself. You're right, steppers and servo motors have just as much torque, or perhaps a tad more at low RPM as they do at max RPM. Nope, rotating a stepper motor by hand with the power turned OFF does no damage. It will generate a bit of voltage and might cause some LEDs to light up a bit.
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After reading a bit more I think the comments on the hobby forums were speaking of stepper motors on small things like cd drives, rc helicopters and little stuff like that. If you think about it on literal terms, no I cannot spin my belt fast enough to crank out 7 amps. But I can totally see nuking the controller on a mini helicopter by hand spinning 7" rotor blades.
 
So I went out and got some steel today to make a new workrest and possibly a new platen that would be a little sturdier to mount the glass to but need to work that out. Got A 4" wide piece of flatbar to make the rest I figure it should probably be about 8 to 10 inches wide but I'm just guessing here. The other thing is I would like to lower the work rest significantly so I could use more of the platen, does that make sense? I got a grinding jig and in order to use it the workrest would need to be dropped by like 2 inches.
 
John GERDING said:
So I went out and got some steel today to make a new workrest and possibly a new platen that would be a little sturdier to mount the glass to but need to work that out. Got A 4" wide piece of flatbar to make the rest I figure it should probably be about 8 to 10 inches wide but I'm just guessing here. The other thing is I would like to lower the work rest significantly so I could use more of the platen, does that make sense? I got a grinding jig and in order to use it the workrest would need to be dropped by like 2 inches.
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I just c clamped a 4x18 piece of 3/16 on my rest to do a couple knives today and I turned it on side to clean up profile and the stock rest+ 3/16 was just barely on the edge of the belt. If you plan to use it in profile also you'll have to have 2 different rests if you drop one basically any. I did shim the platen and drive wheel for better tracking so that could be my issue. But I just added a 3/8 piece of wood between my rest and added plate and it was fine.
 
aareeyesee said:
I just c clamped a 4x18 piece of 3/16 on my rest to do a couple knives today and I turned it on side to clean up profile and the stock rest+ 3/16 was just barely on the edge of the belt. If you plan to use it in profile also you'll have to have 2 different rests if you drop one basically any. I did shim the platen and drive wheel for better tracking so that could be my issue. But I just added a 3/8 piece of wood between my rest and added plate and it was fine.
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So I think what I'm gonna do instead of trying to figure out a way to lower the workrest is get a whole 2x72 platen and just run the 2x48 belts, this way I can use a normal bevel jig and not have to worry about the platen being too small.
 
I still have the Reeder pulled apart while I wire up the 9" disc to the VFD, so I thought I'd clean the frame up real nice in the meantime.

This should at least give you an idea of just how small the Grizzly 2" x 42" is. It's TINY! It actually has a considerably smaller footprint than the Grizzly variable speed 1" x 30" grinder since the 1" x 30" has an integrated disc. It still has a respectable amount of heft to it considering how small it is though.

I am super pleased that the minimum speeds given on the Grizzly website were incorrect. The motor says it's variable from 100rpm - 5000rpm. I don't know how accurate that is, but you can bring this thing down to a crawl... Or make it scream like a banshee.

The platen sucks. The tool rest sucks. But For the price, I think they are more than acceptable. I'll soon be permanently modifying/dropping the tool rest, so that's a non-issue for me. The platen should be more than sufficient for what I'll be using the machine for (squaring blocks in the horizontal orientation).

One thing to keep in mind is that this is a 2" x 42" grinder, not a 2" x 48" grinder (which have more choices for belts). I picked up a bunch of 80 grit belts from Tru Grit from about every manufacturer. I'll only be using this on wood, so the Zirconia (or maybe the aluminum oxide) belts will be all I need, but I figure I'll play around with the machine for a bit.

All in all, I am completely shocked by how nice this seems for the price. I’ll get a more in depth video posted when I have the Reeder back together.

 
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Good review and thanks. I'll be looking forward to when you actually get to do some grinding. I'm VErY impressed how slow it will go. For sure much slower than the 1900 SFPM belt speed in the specs. That looks slow enough. You didn't by chance try to do any grinding at that slow speed to see how much power it had?

The more ya'll talk about this grinder the more I'd LOVE to order one. If the shipping were a bit less - now it's on sale for $270 but with the $70 shipping that makes $340 shipped? Still a good deal it seems. I wonder just how much problem it would be to mod it a bit to take 2X48" belts? Since tru-Grit has 50 different 2X42" belts but 74 of the 2X48" belts that's pretty good. Pop's only carries the 2X48" belts.

I'd sure love to order one - and would "IF" I could figure out a "need" - other than scratching a "want it" itch {g}
 
Ken H> said:
Good review and thanks. I'll be looking forward to when you actually get to do some grinding. I'm VErY impressed how slow it will go. For sure much slower than the 1900 SFPM belt speed in the specs. That looks slow enough. You didn't by chance try to do any grinding at that slow speed to see how much power it had?

The more ya'll talk about this grinder the more I'd LOVE to order one. If the shipping were a bit less - now it's on sale for $270 but with the $70 shipping that makes $340 shipped? Still a good deal it seems. I wonder just how much problem it would be to mod it a bit to take 2X48" belts? Since tru-Grit has 50 different 2X42" belts but 74 of the 2X48" belts that's pretty good. Pop's only carries the 2X48" belts.

I'd sure love to order one - and would "IF" I could figure out a "need" - other than scratching a "want it" itch {g}
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I went to pops last week to get 2x42 and they said the shipment will probably be in this week. So they will have them added to the site soon. I have only been using 2x48 belts. I had to shim the drive wheel and platen and have a 3" tracking wheel coming but it's been working fine as is. I'm probably gonna do the full size platen but it's not necessary to make it work.
 
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