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smitty

Grinder Pro's & Con's

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I need some advice from knifemakers. I would like try to design and build more affordable grinders for knifemakers.With that in mind I would like to get some input on what people like about the sanders they are using as well as what needs improvements. After enough R&D.. I have a engineer buddy of mine,that Im going to see if he can come up with a good design. He is border line genius so I dont think it will be a problem. Everybody seems to love the KMG design. By trade I am a industrial welder/fabricator..so this thing will not be lacking in strength or quality.

 

My goal is to maybe provide a mid-level grinder,that with some frugal saving most people would be able to afford it. THANKS...Kev

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If you will look at my grinder at www.waynecoeartistblacksmith.com/grinders and watch the video I think that you will find that I have addressed these issues.

 

BTW, I am always open to suggestions.

 

 

 

 

Thanks for the reply Mr.Coe. I would like to add " That is a good looking machine you have there " But...And there is no disrespect with this statement. The price is still out of reach for most people just starting out, or just making knives as a hobby. As for myself I started making knives when I was 19,and back then the only sander I could afford was a 1x48...which kinda worked,but it was still like banging your head against a wall !!! And with that being said. I lost interest in making knives. Now that Im 38 and wanting to once again make knives,and being laid-off at the moment....Im back in the same boat ! Not that a perfectly good knife cant be made with just hand tool,b/c thats what Im doing now ! even minus the 1x48 sander !! I would just like to be able to provide a machine that would be a few steps above a Grizzly and such,Just so people wont lose the luster for knifemaking like I did. Maybe even supplement my income some...which is never a bad thing !!! I would be a liar if I said I didnt want to make some profit at this. I just joined this forum/ but I have been coming here for some time...reading,learning and such. You seem like a very honest and stand-up guy from your posts that I have read on other subject's. So I do value your input and thoughts ! And if I had been smart I would have saved my pennies when I was working...I would have a good grinder and wouldnt be undertaking such a task. At the worst I may not come up with a marketable grinder....And at the best I will hopefully build something I can use !

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The polar bear forge Grinder-in-a-box kit is the best I've seen yet in terms of value. It's a kit of water jet parts, shipped flat rate. The customer supplies the motor, wheels, etc. to finish the grinder. Even better, one can get the CAD files to cut out the parts for free (EERF grinder) and do it all in-house.

 

Tooling arm design has pretty much taken over in the world of grinder manufacture, bader and KMG being strong examples. It makes swapping attachments out front really easy, and since the design almost always incorporates rear-wheel drive, changing contact wheel size does not change speed, as on a single speed front wheel drive machine such as the hardcore, burrking, or the two wheel grinder such as the kalamazoo, grizzly, or Coote.

 

Rear wheel direct drive is very good for machines that will be variable speed, as the ease of bolting up a C-face 3phase motor is tops.

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I will have a DVD out soon showing how to build my grinder and with printable pages with stock sizes and all dimensions. The grinder is all angle iron and bar stock.

 

Another way to go is to get the NWG (No Weld Grinder) plans from www.usaknifemaker.com. It is basically all square tubing.

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Wayne Goddard's book, The $50 Knife Shop, has plans for homebuilt grinders that (as the title implies) can be built very cheaply.

 

--Dave

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My laser cut kit can be assembled very affordably. I have a price break down listed at http://www.polarbearforge.com/grinder_kit_breakdown.html that has costs based on brand new parts. Somebody who can scrounge a bit can build it for less.

 

An earlier version of my kit can be found at http://blindhogg.com/eerfgrinder.html,where cad files are available for free.

 

As was pointed out, the NWG is also out there, and the plans that Wayne will be supplying.

 

What price range are you aiming to fill?

 

Jamie

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My laser cut kit can be assembled very affordably. I have a price break down listed at http://www.polarbearforge.com/grinder_kit_breakdown.html that has costs based on brand new parts. Somebody who can scrounge a bit can build it for less.

 

An earlier version of my kit can be found at http://blindhogg.com/eerfgrinder.html,where cad files are available for free.

 

As was pointed out, the NWG is also out there, and the plans that Wayne will be supplying.

 

What price range are you aiming to fill?

 

Jamie

I would really like to get something built in the range of about 400 to 700 minus motor, even lower would be great,but I dont know if it is possible. But I havent even ran any ideas past my engineer/machinist buddy,plus I dont even know what kind of contacts he has, There would be no problem with welding,by trade I am a welder/fabricator

 

I wish this interspaceweb...find anything you need, was around when I was first started making knives,I could have done more research. And not missed out on 19 yrs of knifemaking !!!! Thanks for the info and comments.Its greatly appreciated.

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Wayne Goddard's book, The $50 Knife Shop, has plans for homebuilt grinders that (as the title implies) can be built very cheaply.

 

--Dave

 

 

 

 

I hate to say it but I dont own that book, I know I know....not hardly worth my salt !!!!

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My laser cut kit can be assembled very affordably. I have a price break down listed at http://www.polarbearforge.com/grinder_kit_breakdown.html that has costs based on brand new parts. Somebody who can scrounge a bit can build it for less.

 

An earlier version of my kit can be found at http://blindhogg.com/eerfgrinder.html,where cad files are available for free.

 

As was pointed out, the NWG is also out there, and the plans that Wayne will be supplying.

 

What price range are you aiming to fill?

 

Jamie

If you dont mind me asking,where are you coming up with a 8" contact wheel for 104.00

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I will have a DVD out soon showing how to build my grinder and with printable pages with stock sizes and all dimensions. The grinder is all angle iron and bar stock.

 

Another way to go is to get the NWG (No Weld Grinder) plans from www.usaknifemaker.com. It is basically all square tubing.

 

 

 

I will be looking forward to it !!!!

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The polar bear forge Grinder-in-a-box kit is the best I've seen yet in terms of value. It's a kit of water jet parts, shipped flat rate. The customer supplies the motor, wheels, etc. to finish the grinder. Even better, one can get the CAD files to cut out the parts for free (EERF grinder) and do it all in-house.

 

Tooling arm design has pretty much taken over in the world of grinder manufacture, bader and KMG being strong examples. It makes swapping attachments out front really easy, and since the design almost always incorporates rear-wheel drive, changing contact wheel size does not change speed, as on a single speed front wheel drive machine such as the hardcore, burrking, or the two wheel grinder such as the kalamazoo, grizzly, or Coote.

 

Rear wheel direct drive is very good for machines that will be variable speed, as the ease of bolting up a C-face 3phase motor is tops.

 

 

To true about the Grinder in a box !!!! Wish I had found it years ago ! VFD and Phase converters are somewhat pricey, So at this point Im going to base the design around maybe using step pulleys for speed adjustment !

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I will have a DVD out soon showing how to build my grinder and with printable pages with stock sizes and all dimensions. The grinder is all angle iron and bar stock.

 

Another way to go is to get the NWG (No Weld Grinder) plans from www.usaknifemaker.com. It is basically all square tubing.

 

 

 

 

I really like what you did with the swivel design !

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VFD's are getting a lot cheaper. I use a TECO FM50 203-C, it's a 3 hp VFD that converts single phase 220V to three phase variable frequency 220V. I got mine from factorymation.com, it's the cheapest price I've found anywhere for this product. A lot of knifemakers have used the 2 hp TECO, it's not NEMA-4 enclosed so precautions need to be taken by the user to ensure dust does not get into the drive. There are a few ways of doing this. Here's a link to this drive.

 

http://www.factorymation.com/s.nl/it.A/id.196/.f?sc=2&category=32

 

I wouldn't necessarily recommend an open enclosure drive for use if building a line of production grinders, but it works fine if you take care of it. They are a lot cheaper to get into.

 

I've seen similar VFD's for like $100 on Ebay, they may work well but I can't vouch personally for them. I do know this brand, and factorymation has given me very good customer service as well.

 

With 3 phase motors being cheap or free used in many areas, you could be looking a a total cost of $150 or so for your complete motor/drive setup. Try wrecking yards and metal recyclers, they often have 3 phase motors lying around.

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VFD's are getting a lot cheaper. I use a TECO FM50 203-C, it's a 3 hp VFD that converts single phase 220V to three phase variable frequency 220V. I got mine from factorymation.com, it's the cheapest price I've found anywhere for this product. A lot of knifemakers have used the 2 hp TECO, it's not NEMA-4 enclosed so precautions need to be taken by the user to ensure dust does not get into the drive. There are a few ways of doing this. Here's a link to this drive.

 

http://www.factorymation.com/s.nl/it.A/id.196/.f?sc=2&category=32

 

I wouldn't necessarily recommend an open enclosure drive for use if building a line of production grinders, but it works fine if you take care of it. They are a lot cheaper to get into.

 

I've seen similar VFD's for like $100 on Ebay, they may work well but I can't vouch personally for them. I do know this brand, and factorymation has given me very good customer service as well.

 

With 3 phase motors being cheap or free used in many areas, you could be looking a a total cost of $150 or so for your complete motor/drive setup. Try wrecking yards and metal recyclers, they often have 3 phase motors lying around.

 

 

Thanks for the link !!!! If we do come up with a design and maybe get this rolling,prob will offer it without motor to keep the price as low as possible. Got to have the link though,going to need a motor and vfd for a prototype ! Plus if any get sold can pass along the info !

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I love the polar bear grinder in a box design.

 

I have been thinking of a similar design but using a sheet with a steel box of 1.5" ID welded or bolted to it for tool arm rather than the bolted multiple piece design. With face mount and plate you have a simple start. Tracking/tensioner arm pivots from the sheet as per grinder in a box.

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A lot of knifemakers have used the 2 hp TECO, it's not NEMA-4 enclosed so precautions need to be taken by the user to ensure dust does not get into the drive. There are a few ways of doing this.

 

Salem,

 

Can you be more specific on some of those ways? I have a massive old 3 HP, 3-phase motor (it has to weigh over 100 pounds) that I bought for $25 with visions of power hammers dancing in my head. But that won't happen unless and until I move, so for now I could use it to build one beast of a belt grinder, if I could provide 3-phase from single phase 220. The NEMA-4 VFDs are too rich for my blood, but some of the unsealed ones on eBay might just be in the budget.

Edited by Matt Bower

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If Matt Walker sees this he may chine in, but he has one of those unsealed VFDs on his rolling mill. It's sealed in an old tool box with a CPU cooling fan on both ends with little filters on 'em, works great.

 

 

 

http://www.matthewdwalker.com/visit_my_studio/vfd_mounted_in_a_tool_box.html

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Thanks, Alan. Looks neat. I know those CPU fans can be really cheap. Wish I had a little more self-confidence (the justified kind, not the "too dumb to know what he doesn't know" kind) when it comes to dealing with electricity.

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Hey Alan,

Yeah I've been using that system on my grinder in a very dirty shop for several years now with no problems. At $145 for a 2 HP VFD and $185 for a 3HP unit, seems like a good way to go to me. I didn't actually use the small fan, after consulting our Phd. electrical engineer friend, he advised it wouldn't be needed in a box that big. I did bolt to a 1/4" piece of aluminum in the bottom of the box for additional heat sink, but it never gets all that warm.

http://www.factorymation.com/s.nl/sc.2/category.32/.f FM-50-203-C

 

Matt

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I love the polar bear grinder in a box design.

 

Thanks!

 

I have been thinking of a similar design but using a sheet with a steel box of 1.5" ID welded or bolted to it for tool arm rather than the bolted multiple piece design. With face mount and plate you have a simple start. Tracking/tensioner arm pivots from the sheet as per grinder in a box.

 

I've done it, and it will work. I ended up making a few different versions along that line. It wasn't quite what I was looking for though. Make sure when you build it that you share pictures!

 

Jamie

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Hey Alan,

Yeah I've been using that system on my grinder in a very dirty shop for several years now with no problems. At $145 for a 2 HP VFD and $185 for a 3HP unit, seems like a good way to go to me. I didn't actually use the small fan, after consulting our Phd. electrical engineer friend, he advised it wouldn't be needed in a box that big. I did bolt to a 1/4" piece of aluminum in the bottom of the box for additional heat sink, but it never gets all that warm.

http://www.factorymation.com/s.nl/sc.2/category.32/.f FM-50-203-C

 

Matt

 

Thanks, Matt. That's great to know. So the fan really isn't necessary? Does that mean you don't really need the filters, either?

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Thanks, Matt. That's great to know. So the fan really isn't necessary? Does that mean you don't really need the filters, either?

 

Matt, I believe the oversize filters are a good idea. The VFD has an onboard fan and the filters allow some clean air flow. With the on/off, emergency stop and speed pot mounted in the lid, the box seldom ever needs to be opened.

 

Also consider the 3 HP isn't that much more than the 2 Hp. In the future if you run up on a lathe, surface grinder or some other equipment, with a receptacle on the VFD and plugs on machines the box can simply be carried over to run unlimited other things up to the capacity of your VFD.

 

Matt

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Smitty, as mentioned here you can get some kind of external case or box and mount the VFD in it with a fan, filter, whatever you deem necessary. My easy solution: I have a grinding room, so I mounted the VFD on the wall outside the grinding room under a shelf where very little dust can fall in. I built a remote box next to the grinders, and ran the wires from the switches and speed pot through the wall to the VFD. I have two grinders and a 50# Little Giant running off it right now. Occasionally I use the compressor to blow the VFD vents out a bit, too. I do this with the power to the VFD off so shifting dust doesn't cause any shorts.

 

Works great so far.

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