Thread: No weld grinder. Troubleshoot me.

I'm building a grinder based on the plans for the NWGS from USAKnifemaker. Here's the thing. The plans call for 1.75 inch, 2 inch, and 4 inch square tube steel. I happen to have access to some free tube steel in sizes of 2 inch, 2.25 inch, and 3 inch. So, of course I'm using that instead. The two things I see that may cause problems with this idea are 1: I won't be able to use commercially available tool arms, and 2: I may have to bolt the pillow blocks to a piece of plate steel that's 4 inches wide.

So the question is: What other problems do you think I might encounter?

Building a toolrest should be easy compared to the rest of the project. Are you talking about bolting the PB to 4" plate rather than tube?
Projects like this are damned to offset/spacing issues. I suggest taking a few hours to modify the plans to accept your available materials.
I have never built a grinder like this, but I have built a pile of food processing, packaging equipment, and other related nonsense.
Why a no weld unit btw?

Yes, I'd stack it if that makes sense. I'm assuming the pillow blocks won't fit on the 3 inch wide base side by side. So I thought I might have to get 4x4x 1/8 plate to act as a base for them.

And the reason for no weld is 1: I don't have a welder, 2: I don't know how to weld. It's on the list for future learning, but not prior to this construction.

Thanks for your input.

Be careful and take your time tapping the threads...I broke a tap on mine and had a bugger of a time getting around it. Fortunately I had access to a welder and it was a simple spot to weld stuff in place.

My system has yet to run. I purchased a 3ph motor new, then a controller just like Undreams...damn thing literally won't go and I'm stuck as I know nothing about troubleshooting a controller system like this. I've been disgusted with it and just walked away from it over 6 months ago.

For my toolrest I haven't figured out what I am going to do yet either. It's got to be solid, yet adjustable IMO. For the adjustable parts using tube steel, I'm afraid you will have to find someone to spot-weld some nuts in place as the wall of the tubing more than likely wouldn't have enough thread if you tapped it.

Hey, Shooter, what kind of a phase controller do you have? I just set up a 3phase motor and AC controller, and it works great - I may be able to help. My controller is an LG Space Vector Control, model iS3. My supplier knows them backwards and forwards and was able to talk me through the setup procedure.

Shooter, I'm sure you've considered it before, but the knife forums have several photos of VFD wiring systems fully wired and running. I just signed up with Knifedogs.com and USAknifemaker. Both have a ton of info.

I'm using a Reeves pulley for variable speed, so I won't need to worry about any wiring. Looks like my project just stalled as well though. 283 dollars for JUST the wheels, drive shaft, and pillow blocks. Learning is darn expensive these days...

I have built 4 of the NWG so I have a bit of experience with these. You want to mount the pillow blocks as far apart as you can so size the plate to mount them on accordingly. This will reduce the stress on the pillow blocks. I used self aligning bearings/pillow blocks.

The 1.75 inch tube is to be used as the tool arm. It is to fit inside the 2" tube. But...my tubes had seams on them inside. The seam on the inside of the 2" tube made it impossible for the 1.75" tube to fit inside. So I had to take an angle grinder and grind down the 1.75" until it slid inside the 2" tube.

The drive wheel, tracking/tension wheel and the contact wheel are a major expense in this setup. A good source for wheels is Polyurethane Wheels | Drive Wheel | Polyurethane Products

Sunray-inc.com

make sure the width of the drive wheel and the tension/tracking wheel are the same and that both are crowned . This keeps the belt centered much better.

The spring to use for tension is nothing more than a screen door spring.
On your bolts be sure to use lock nut washers.

Motor....Skipnord and I disagree on this but I feel that a 1 HP motor is more than adequate. A larger motor is better if your going to be really hogging off the steel but for razors that is really not necessary. A VFD is nice but once again not necessary. A pulley system will get you want you want. As was expressed to me by an experienced razor grinder the real question is just how slow can you make it go. The slower the better for final grinding. You don't want to burn your steel or make a big mistake. The faster the wheel the bigger the mistake.

Hope this helps,

OK, Randy - I'll clarify my motor size comment. If all you are going to do is finish grind razors that are forged to rough shape, 1 hp is probably adequate. If you are going to do stock removal, the more power the better. My motor is a used 3hp 3 phase, with an AC converter to control the speed and convert to single phase operation. I have any speed from 0 to around 3300 rpm, and this is ideal, from my perspective. Charlie gets by with a very small motor and a 1x42 belt size, and that works great for his method of grinding. We all know the incredible quality of his work. I want enough power to be able to do anything I can think of on my grinder. Actually, the variable speed may be more important than power for most of us.

Originally Posted by skipnord

Hey, Shooter, what kind of a phase controller do you have? I just set up a 3phase motor and AC controller, and it works great - I may be able to help. My controller is an LG Space Vector Control, model iS3. My supplier knows them backwards and forwards and was able to talk me through the setup procedure.

I followed Brad's lead and used this VFD: 2HP 230 Volt -- USE AS A PHASE CONVERTER PLUS GET VARIABLE SPEED, Model JNEV-202-H1, Single Phase Input ONLY, Three Phase Output, variable frequency drive, variable frequency drives, ac drive, vfd, afd, frequency drive, drive, inverter, adjustable sp

So, have you figured it out and got it working? It's not the same one I have, but it is the same type of control - cost $10 less than mine. Let me know if you still haven't got it working - maybe I can help - my email is skipnord@comcast.net