KMG Clone Makers

[Themilkman]

Hi All,

So I got my newly built grinder up and running, and at least that will let me keep making blades in the meantime. It isn't the most true running, and has quite a bit of shake, so I am considering building something a bit more solid. No cutting corners or trying to use cheap/scrap material on this one. I am thinking about wither doing a KMG clone, or something like a Wilmont with Sayer OSG plans or EERF plans.

The KMG clone looks a lot simpler, and seems to use less materials as well. I was thinking about finding or making CAD drawings of it, then having my local steel supplier (NJ Steel Baron) water jet it for me. That will give me precise, square pieces, and even have most to holes accurately placed.

For those of you that have made the KMG clone, did you water jet, or measure and drill yourself? I am a fairly careful fabricator, but aligning and drilling all those drill perfectly by hand has to be close to impossible. You can scribe and center punch, but even if your center punch is off a hair or slightly angled, the whole thing will get screwed up. I have no mill or lathe too, so waterjet seems like the best option.

Thanks in advance!

 

[12345678910]

The kmg clone uses more material - it's there in thickness.
In my area, the cold rolled is also twice the price of plate or cold rolled.

It's all barstock, there is nothing to hole drilling is easy to line up, once you know how.

I'd do a Sayber, especially if you can get it jetted.
Direct drive, flipper.

 

[Ken H>]

Here is one of the easiest 2X72 grinders to build, just order the aluminum in sizes needed and drill holes to put together. The big single plate makes sure the 56C mounted motor is lined up correctly. Look thru this thread for ideas. bjansen has done a good job with the plans.
https://www.bladeforums.com/threads/2x72-grinder-build-2018.1577263/

 

[bjansen]

Check out this updated thread for the most current version of the plans. I made my first couple grinders using the KMG clone plans, but I significantly prefer the model in these plans. In my view it is much easier to use, quieter and easy to make as well. Good luck

https://www.bladeforums.com/threads/free-2-x-72-belt-grinder-plans-2020-version.1705344/

 

[P.Brewster]

I was thinking about finding or making CAD drawings of it, then having my local steel supplier (NJ Steel Baron) water jet it for me. That will give me precise, square pieces, and even have most to holes accurately placed.

For those of you that have made the KMG clone, did you water jet, or measure and drill yourself? I am a fairly careful fabricator, but aligning and drilling all those drill perfectly by hand has to be close to impossible. You can scribe and center punch, but even if your center punch is off a hair or slightly angled, the whole thing will get screwed up. I have no mill or lathe too, so waterjet seems like the best option.

Thanks in advance!

Your understanding of waterjet is a bit off. Comparatively speaking, it isn't very precise - it's good at putting holes in accurate positions, but poor at cutting a surface that is perpendicular to the stock surface and planar. The KMG construction relies on butt joints, which means you're going to run into some trouble here, and when the cost of waterjet cutting is considered, I think the idea can be thrown out all together. The precision you'll find on regular cold-drawn mild steel bar will far exceed anything a waterjet can do. On the main frame of the KMG, there are exactly 2 pieces that need to have 2 adjacent square surfaces (the support blocks for the drive shaft). All other components can use a rough-cut for 2 surfaces, and the as-is condition for the remaining 4 surfaces (each piece being a rectangular solid with a total of 6 surfaces)

You can produce a cut surface that is better than waterjet in terms of perpendicularity and flatness by bandsawing a bit oversized, then trueing up the cut surface on another belt grinder with flat platen, work rest, and a combination square. Obviously this will require a friend with a belt grinder or a second preexisting belt grinder of your own.

As for accuracy of the hole location, I think you're overestimating the criticality of it. If you go by standard hole clearance rules, your through-holes for 1/4-20 bolts will be oversized by 1/32" which gives you a lot of play. Work smart - o build the receiver, for example, start with the top and bottom pieces. Layout your hole locations on one piece only, and either (a) drill that and transfer the hole locations to the second piece with transfer punches, or (b) clamp both pieces together and drill in one shot.

There are steel suppliers who sell pre-squared blocks of steel made to order. Use them if you're worried about it, and then all you need to worry about is drilling and tapping holes.

 

[Themilkman]

Thanks for the replies. Some of those links will prove to be very helpful. I also never heard of a transfer punch, but after some research I found how I could have used them numerous times in the past. I like bjansen's build a lot! Thanks for all the comments

Is there anyone with current KMG clone plans too by the way? The previous threads that had them, the links don't work anymore.

 

[Themilkman]

Check out this updated thread for the most current version of the plans. I made my first couple grinders using the KMG clone plans, but I significantly prefer the model in these plans. In my view it is much easier to use, quieter and easy to make as well. Good luck

https://www.bladeforums.com/threads/free-2-x-72-belt-grinder-plans-2020-version.1705344/

For your grinder, is there a function for the third tool slot, or does that just make the construction easier? Also, when comparing an aluminum vs steel frame, do you find the aluminum to be less stable/ more shaky than the steel/

Thanks, and awesome plans!

 

[12345678910]

Thanks for the replies. Some of those links will prove to be very helpful. I also never heard of a transfer punch, but after some research I found how I could have used them numerous times in the past. I like bjansen's build a lot! Thanks for all the comments

Is there anyone with current KMG clone plans too by the way? The previous threads that had them, the links don't work anymore.

The plans I saw, you cannot blindly follow. There is a mistake in them.

 

[John mc c]

I followed kmg clone plans on dcknives site,couldn't be easier and it runs true

 

[Ken H>]

For your grinder, is there a function for the third tool slot, or does that just make the construction easier? Also, when comparing an aluminum vs steel frame, do you find the aluminum to be less stable/ more shaky than the steel/

Can't imagine need for 3rd tool arm slot, but not hard to do with the plans. Great set of plans and were I building a new 2X72 grinder they are what I'd use.

Aluminum construction is for sure as sturdy as steel construction and easier to work with, and perhaps less expensive. The ONLY drawback I've seen to aluminum is threaded screw holes that are in constant use, and that's easy solved by use of heli-coil inserts.

 

[noseoil]

If you can weld, think about something like this. Pretty basic steel, parts were "off the shelf" receiver tube from trailer hitch stock (2" + 2 1/2" tube) & 1/4" plate stuff. It might be a bit challenging, but it's rock-solid, runs well & serves the purpose for my needs. You could do a single tube version, but I wanted the ability to add tool rests & did a twin tube design.

 

[bjansen]

Yep -same as Ken said. I have been using my 6061 grinders for 7 years now and zero issues. I do use threaded inserts for all the 5/16 bolts that are used regularly (i.e., the tracking knob and the tightening knobs).

the third slot is not much use other than if your bench is too high you can drop everything down a slot to lower the center of the tool. I also use the lower one to move the work rest down to grind in clips using a jig (gives me more room)

123 I dont think there are too many flaws or mistakes in my plans (if you were talking about mine that is). You definitely need to get your head around how it all goes together which is why I did that build along. After you do that, these things are simple to build.

 

[Themilkman]

Thanks for the replies everyone, some great things to consider!

 

[Themilkman]

If you can weld, think about something like this. Pretty basic steel, parts were "off the shelf" receiver tube from trailer hitch stock (2" + 2 1/2" tube) & 1/4" plate stuff. It might be a bit challenging, but it's rock-solid, runs well & serves the purpose for my needs. You could do a single tube version, but I wanted the ability to add tool rests & did a twin tube design.

I built my current grinder very similar, except I used a vertical tensioner rather than the swing arm type. I think a major issue with the build was the stand and hinged motor mount, causing a lot of vibration. With your grinder mounted to the bench, how stable/shaky is it? And can you post or message me some more details, such as your motor setup and some closeups of the swing arm and tensioning hinge? I thought about doing a direct drive single speed like you, but not sure if it was worthwhile. I do forge my blades, so I don't really need metal hogging speeds to get bevels in. Thanks

 

[12345678910]

Thanks for the replies. Some of those links will prove to be very helpful. I also never heard of a transfer punch, but after some research I found how I could have used them numerous times in the past. I like bjansen's build a lot! Thanks for all the comments

Is there anyone with current KMG clone plans too by the way? The previous threads that had them, the links don't work anymore.

The plans I saw, you cannot blindly follow. There is a mistake in them.

123 I don't think there are too many flaws or mistakes in my plans (if you were talking about mine that is).

I refer to the Micheal Cleric Kmg clone plans that he asks about in the post that I quoted.
https://www.bladeforums.com/threads/kmg-oem-spring-specs.816524/

If you're going to build one, do direct drive, flipper, vfd variable speed.

 

[noseoil]

"I built my current grinder very similar, except I used a vertical tensioner rather than the swing arm type. I think a major issue with the build was the stand and hinged motor mount, causing a lot of vibration. With your grinder mounted to the bench, how stable/shaky is it? And can you post or message me some more details, such as your motor setup and some closeups of the swing arm and tensioning hinge? I thought about doing a direct drive single speed like you, but not sure if it was worthwhile. I do forge my blades, so I don't really need metal hogging speeds to get bevels in. Thanks"

If you had a hinged motor mount, I don't there's really a need for a second tensioner. The weight of the motor is sufficient to tighten the belt, if the geometry is correct & the weight of the motor is sufficient. Take a look at an older Craftsman table saw, the motor works as the belt tensioner & there's no adjustment for the belt.

On mine, the motor is simply mounted to the 1/4" base plate & won't move. I chose to use a swing arm & tensioner (gas strut) as it's easier to use for me that way. I did need to swap the original strut for one which wasn't as strong (don't remember which is which or the force needed any more), but it put too much tension on the belt when I first set it up. The belt just needs to be tight enough to not slip when you lean on it. The hinge is simply a 3/8" bolt (edit, size) which is drilled through the 2 ears which stick up from the rear vertical tube. It's really pretty crude the way I did it, but effective. There's no vibration with my setup at all & it runs smoothly. There's also a lot of mass with the motor bolted down, 1/4" steel tubes & plates & the running gear adds a bit more weight. Didn't weigh it, but I'd guess it's about 80# in the picture I included. Here's a picture of the frame welded up & ready for a finish coat of paint & assembly. Hope this helps with my explanation.

 

[Themilkman]

"I built my current grinder very similar, except I used a vertical tensioner rather than the swing arm type. I think a major issue with the build was the stand and hinged motor mount, causing a lot of vibration. With your grinder mounted to the bench, how stable/shaky is it? And can you post or message me some more details, such as your motor setup and some closeups of the swing arm and tensioning hinge? I thought about doing a direct drive single speed like you, but not sure if it was worthwhile. I do forge my blades, so I don't really need metal hogging speeds to get bevels in. Thanks"

If you had a hinged motor mount, I don't there's really a need for a second tensioner. The weight of the motor is sufficient to tighten the belt, if the geometry is correct & the weight of the motor is sufficient. Take a look at an older Craftsman table saw, the motor works as the belt tensioner & there's no adjustment for the belt.

On mine, the motor is simply mounted to the 1/4" base plate & won't move. I chose to use a swing arm & tensioner (gas strut) as it's easier to use for me that way. I did need to swap the original strut for one which wasn't as strong (don't remember which is which or the force needed any more), but it put too much tension on the belt when I first set it up. The belt just needs to be tight enough to not slip when you lean on it. The hinge is simply a 1/2" bolt which is drilled through the 2 ears which stick up from the rear vertical tube. It's really pretty crude the way I did it, but effective. There's no vibration with my setup at all & it runs smoothly. There's also a lot of mass with the motor bolted down, 1/4" steel tubes & plates & the running gear adds a bit more weight. Didn't weigh it, but I'd guess it's about 80# in the picture I included. Here's a picture of the frame welded up & ready for a finish coat of paint & assembly. Hope this helps with my explanation.

Is your motor fixed speed, or was there a vfd hooked up to it? I'm thinking about doing a fixed speed direct drive with my current motor, until I save up and find a cheap vfd system to get me started off ebay or somewhere.

Now I have to decide, attempt the tubing grinder again, or try something different such as the KMG clones posted. Hmm...

 

[noseoil]

Mine is a fixed speed setup, but if I did it again, I'd use a 3450 motor instead of the 1800 rpm model I have. After looking at other people's work, the faster speed would be a lot quicker to use for profiling. Granted, I would be SOL with the finer grit belts, but that's just the way it goes. Life can be a compromise at times. A VFD would be the best of both worlds, but it does cost a bit more...

P.S. Sorry didn't mean to hijack this thread. Apologies to the OP.