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Grinder in a box! DIY grinder kit

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I've gone the route of adding a nut between the wheel and platen. I've also use a modified washer to go there as well, either will work. When I used the nut, I actually drilled it out so that it was basically a thick, hexagonal washer. It was dual purpose, to serve as a way to tight down the bolt better on the bearings, and a spacer to move the wheel over a bit.

Jamie
 
So I just ordered my wheels, and in a few weeks I will be ordering my VFD. If everything goes right I will have an operational grinder for Christmas.

I wasn't sure what size platen to order so I just went with the 5" one, I know if its a little on the short side it will still fit in. I should be painting the chassis Monday or Tuesday.

Now all I need is a place to set it up and start grinding:thumbup:
 
Thought I'd post a vid of my completed grinder. >click here<

p1000005v.jpg


To speak to the contact wheel/bearing issue, I had the following experience.

When I first mounted the wheels (8" & 3" poly contact wheels, "economy" versions from USAKnifemaker), I used a 1/2"-13 bolt and washers/bushings to space the desired amount. I tightened the bolt until the wheels had no play, but during operation the bearings would heat up. Not just a little, but a LOT! Obviously, this is not right. I took the wheels off and looked them over and it made sense. Not sure why I didn't get it before, but there you go!

The wheels have bearings pressed into each side, but there is no through bushing. The wheels that Rob sells at Beaumont Metalworks do have internal bushings, and over tightening is a non-issue. But I didn't have another $170 to spend, so I fixed the problem much like Jamie did with his build: I mounted each contact wheel to the platen with 1/2"-13 bolts, using a jam nut to secure the bolt to the platen and to eliminate play or it being rattled out of place. I used machine bushings (1/2"x5/8") to take up slack where necessary. There is no side pressure on the bearing races because I used 3-1/2" bolts, which have a roughly 2-1/16" unthreaded shoulder--perfect for the contact wheel to ride on. This solves the problem for the cheaper wheels, and eliminates side pressure on the bearings, which will ruin them pretty quick.


By the way, I talked to Tracey at USAKnifemaker.com the other day and he told me that his contact wheels (the polys) are different from Sunray in that his have a tolerance of 3-4 thousandths-of-an-inch in side-to-side play; whereas, those from Sunray supposedly have more. It came up because I measured the total variance in side-to-side motion on my 8" wheel to be ~12 thou.

Hope this helps.

JJ
 
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I still haven't received my wheels yet, so I don't know if it is possible to do, but could you not just pull one bearing insert a sleeve and press the bearing back in? I know that it really depends on if you could get a hold of the outer race on the inside of the wheel to pull the bearing. With any luck my wheels will be here tomorrow and I can answer my own question
 
unky_gumbi said:
could you not just pull one bearing insert a sleeve and press the bearing back in? I know that it really depends on if you could get a hold of the outer race on the inside of the wheel to pull the bearing. With any luck my wheels will be here tomorrow and I can answer my own question
Click to expand...

That was an option. But to be honest it is much easier to mount the wheel in the fashion I described above. Putting an internal bushing between the bearings would be tough on these wheels since the hub is machined to house the bearings and obscures access to the outer race from the inside, making it difficult to punch them our or get a slide hammer to grab hold.

Let us know if you have any luck if you choose to go this route.

JJ
 
well, it started
motor is secured
55216_1699033644926_1510454849_31679930_2844575_o.jpg
[/IMG]
maybe little underpowered but
it was free :)
parts are on the cutting as I write (little mishhaps whit conversioon to mm but hopefully everything will go ok)
updates as I progress and all comments are welcomed
for wheels I plan to use skateboard wheels if evilbay likes me :D
then belts
this will probleably be the biggest problem but I will overcome it :D
 
lustrum said:
That was an option. But to be honest it is much easier to mount the wheel in the fashion I described above. Putting an internal bushing between the bearings would be tough on these wheels since the hub is machined to house the bearings and obscures access to the outer race from the inside, making it difficult to punch them our or get a slide hammer to grab hold.

Let us know if you have any luck if you choose to go this route.

JJ
Click to expand...

My wheels came in today, and I had a chance to look at them. I could pop out one of the bearings on each of the contact wheels, but like you said they have no access to the outer race so the chances of ruining the bearing is pretty high. They aren't the highest grade of bearing either. My problem is that my $50 motor has a shorter shaft and with the set screw right at the edge of the shaft I only have 1/2" of clearance from the main upright. It looks like a bearing upgrade and making an sleeve for the inside of the wheels is in my future because I don't have the space to run jam nuts. It's OK though because it will be about a month before I am ready to run the grinder any how
 
It depends. I built all of mine with the motor on the right, so it's spinning clockwise. If you build it with the motor on the left, then it would have to be counter clockwise.

Jamie
 
Is there anyway to buy/build a 110v variable speed 1.5hp elec motor? I guess hooking a standard dimmer switch up is not advisable? :eek:

I want variable speed, but only have 110v access in my garage.

edit:
electricity is something I know nothing about....
 
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Yes, Rob at Beaumont Metal works has a 1.5 horse motor with a 110 powered vfd, so it is possible.
 
caver101 said:
Is there anyway to buy/build a 110v variable speed 1.5hp elec motor? I guess hooking a standard dimmer switch up is not advisable? :eek:

I want variable speed, but only have 110v access in my garage.

edit:
electricity is something I know nothing about....
Click to expand...

You need a 3 phase motor and a VFD that is capable of running off of 110 single phase input. I am in the same boat, and there are a few to choose from. I have decided to go with the KBAC-27D, simply because I have seen so many of them being used on other grinders and if I am ever in a position to run 220V input the VFD is capable of that too:thumbup: Only thing about the KBAC-27D is that you can expect to pay between $350-$400 for one after shipping, well worth it in the long run I thing from all the reviews I have read.
 
Thanks for the info. Let me ask this last question:

I can NOT use a VFD on a 110v single phase motor to make it variable speed, correct? Is there a way to make a single phase variable speed? (ok, that was two questions :D)

I can get a free 1.5hp single phase 110v motor is the reason I ask.

Thanks in advance :thumbup:
 
You might be able to use a variac to make it variable speed, but I think you lose torque this way...probably lose torque with single phase anyway you try to control the speed..Someone with more knowledge than me will chime in :)
 
caver101 said:
I can NOT use a VFD on a 110v single phase motor to make it variable speed, correct? Is there a way to make a single phase variable speed? (ok, that was two questions :D)
Click to expand...

Looking around a bit online, it appears that there are some meant to do this,but they appear to be meant for fans and blowers, as well as only working with a select group of single phase motors.

All of my grinders use a single speed, single phase motor.

Jamie
 
Has anyone used step pullies and flange bearings on one of these to make it variable speed? I already have the motor but would rather have variable speed when all is said and done.

Would I have to use a pillow bearing and flange bearing where the motor would be, or is there room to put two flange bearings. One on each side of the frame where the motor would mount?

Jason
 
jawilder said:
Has anyone used step pullies and flange bearings on one of these to make it variable speed? I already have the motor but would rather have variable speed when all is said and done.

Would I have to use a pillow bearing and flange bearing where the motor would be, or is there room to put two flange bearings. One on each side of the frame where the motor would mount?

Jason
Click to expand...

As far as I know, this has not been done. It was meant to use a face mount motor rather than step pulleys.

I know that the flange bearings I have in the shop aren't big enough to span the opening where the motor goes.

Jamie
 
Jamie, I haven't had a chance to tell you yet, but thanks a lot for sending the GIB so quick! I ordered it Thrusday, it shipped Friday, New Year's on Saturday, and it came on Monday. I couldn't believe how fast it got here!

I have it put together and am working on getting the right bearings for a step pulley setup. I'll let you know as it progresses.

Thanks again for making my dream of having a reasonably price 2x72 possible!
Jason
 
so to make sure i have this right, if i mount the motor on the right i dont have to rewire the motor to CCW?

jake
 
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