Making a frankin-grinder. Looking for some suggestions

R

Railrider1920

Joined
Dec 14, 2010
Messages
403
Hi Folks,
I would like to try to make a frankin-grinder and I thought that I would run it by you kind folks here, see what kind of suggestions you might make. I don't have the money for a real grinder right now, but I want to do some grinding. So I have to make due with what I have on hand, spending as little as possible. I'd like to hear your thoughts on what I have come up with along with any suggestions you might have.
Whats a frankin-grinder you ask? It's a grinder like machine that is made from parts or made in such a way that you would not expect it to be made into a grinder. One example (IMO) would be the grinder made out of a tread mill.

I am starting out with a belt / disk sander just about identical to this harbor freight sander. Only mine was broken at the pivot point. I got it for $20 from a flea market type place. I figured I could do something with it.
http://www.harborfreight.com/media/c...image_2138.jpg
P2159297.jpg

Base and motor. Broken pivot on right side.
P2159320.jpg


I have this piece of rectangular steel. Two of these 1.5" x 1.5" tubing fit inside of it pretty well. The 1.5" tubing would be the tooling arms. I will try to weld a piece of steel in to the middle to keep them separated and take up some slack. The piece I want to use as a receiver, the piece for the upright on the tracking arm and the two 2x2 pieces are pretty heavy stuff, 1/8" thick. They all came off of a big piece of home work out machine.
receiver.jpg


I would take this receiver and tool arms and weld or bolt them to the top of the belt sander bed, which is cast iron. Can cast iron be welded?
P2159302.jpg


Along side of this, I would put up some kind of an upright for the tension and tracking arm.
P2159317.jpg


I'm not exactly sure how I will set this up so that it is up off of the work bench enough to slip a belt onto it. One thing I'm thinking about doing is cutting some notches in the sides of the cast iron base large enough to slip these 2x2 tubes from one side to the other so that it rests on these. Then bolt down the other ends to a base. With both rollers on it, the belt that goes on it leaves a gap between the bottom and the belt of about 1/2" to 3/4", so I think this will leave enough room.
P2159330-1.jpg


This is the front roller. The sides are solid with bearings in them, but the inside is hollow, so I don't think it could be cut down to 2". I am thinking about making some kind of bracket to hold it, attaching it to a tooling arm and using it as is. Or possibly using it as the bottom wheel on a flat platin (SP?)

P2159315.jpg


I mocked up this "platin" using the center hub from large lawn mower wheels. They are plastic with bearings in them. No idea how they would hold up or how long they would last. I might give it a try.
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I am planning on using a 4 step pulley on the base and a 3 or 4 step pulley on the motor. The one on the base, I'm planning on putting the smaller end in toward the base so the opening of it is out so that I can slip on the 9" disk. Then drill a hole in the largest pulley so that I can get to the set screw on the disk.
P2159311.jpg


Funds right now prevent me from going out and buying some good wheels So I will have to make due with what ever I can find and make work. I just remembered that I have a tire from a riding lawn mower that is hard rubber. I turned it down so that it is nice and flat and about 2 1/2" wide by bout 10". I might give that a try. Today I found a nice piece of angle iron to use for a platin.

So.......
Can cast iron be welded?
Any recommendations on where to place the tooling arm receiver? Towards one side or the other? in the middle?
I will probably give the metal a bath with a battery charger to get rid of the rust. After that, how can I coat the insides of the tubing to keep it from rusting? Is there a better way than just spray paint?
So what do you folks think? Is there anything that stands out and and yells don't do this? Would you do something differently from what I have described? Anything I should add or get rid of?

Thanks for your thoughts and opinions,
Rob
 
Craftsman 2x42. Much easier and much much cheaper in the long run. Not as much fun though.

I do think it's neat, though. I like watching builds like this. Build on sir! I have no further suggestions and should probably go to bed now. Lol
 
I believe you could also call this device a contraption. Am I right? carry on. I wish you the best ! A 2" grinder is soooo good to have for making knives. Frank
 
Seems like you're having a good time with your project, and that's half the point, I imagine.

A couple of thoughts.

1) How are you planning to attach the upright to the base? And how will you insure it remains at a perfect right angle to the base?

2) What is the power rating of that motor?

3) What are you planning to use for a drive wheel?

4) How will you adjust the tracking?
 
I used to have that HF 6x48" sander and entertained the idea of turning it into a 2x72" for a while. If you've got a lot of time, some parts to work with, and little or no money to spend, it can't hurt to try. If it gets to the point where you have to lay out $ to get it running, you might look into the craftsman 2x42. The motor on my HF was not terribly inspiring in terms of power, so without upgrading the motor you might not get much more out of this than the 2x42, other than variable speed with the step pulleys, and the longer 72" belt. I won't tell you not to try, because building equipment, machines and fixtures is a hobby in itself for some of us (some might call it an affliction:confused:)
 
Rob, Hey I was just wondering about you the other day, glad to hear you are still at it!

Yes you can weld cast with the proper rod. I think you told me you had a stick welder.Check out this page at the bottom click on the link for cast iron consumables http://www.lincolnelectric.com/en-us/consumables/stick-electrodes/Pages/stick-electrodes.aspx

Sometimes I love fabricating almost as much as I do anything else. Hey I am going to shoot you some links on different grinders. Maybe you will want to change your school of thought and try something a little closer to one of those. If you can build something like a KMG clone using the wheels you got until you can afford better I think you will be more pleased with the result.

A couple of things I will tell you about fabricating a grinder. One you have already heard you need a provision for tracking in your design. Two every thing needs to be square, or it will not track and you will constantly be having to chase the belt. Here are those links. Some of them may be useful and some may not., sort through them and you may get some ideas that will help out in your build

http://forums.dfoggknives.com/index.php?showtopic=7564&
http://www.cootebeltgrinder.com/
http://www.bladeforums.com/forums/showthread.php/565812-DIY-2x72-Belt-Grinder-Video
http://www.bladeforums.com/forums/showthread.php/851721-Meet-My-Mistress-Belt-Driven-GIB-EERF
http://www.bladeforums.com/forums/showthread.php/606747-Share-pictures-of-your-Grinder
http://knifedogs.com/showthread.php?7390-World-s-best-thread-about-grinders
http://www.garagejournal.com/forum/showthread.php?t=41867

Here are the plans I used to make a KMG clone. http://www.dfoggknives.com/PDF/GrinderPlans.pdf I have links for some metal places that you can order the metal cut to size. It costs a little but all and all when said and done you will have a lot less than what you would have paid for a KMG. However if you can't control squareness of the build the basic KMG without motor is a good investment. That way all of the quality is already built into the machine. Motors, pullies,bearings can all be purchased on line that are the equal to the KMG, just food for thought.

There is another one that is 2x72 design that I almost built and is a good design if I can find it I will post it for you. It was similar to the design of the one about halfway down on this page, in red, posted by SCMKnives I made several posts back and forth with the guy and he had all the problems worked out. But I lost the link in a PC crash about a year ago!
http://www.customknivesandguns.com/ckgforums/showthread.php?t=29891

Feel free to shoot me a email if you want to talk about something with your build. I know the wheels are turning in your head but you need to think out the variables before you put a lot of effort into something that doesn't work well.
 
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cast iron needs very low heat or it will just burn up its very hard to weld i use stainless rod on the 50 amp setting
 
It's also a good idea to preheat the cast iron to above 500 degrees with a torch before welding, a large area around the weld zone. If you get a tempil stick for 5 or 600 from your welding supply it will help guage temp.
 
Franken-grinder! I love it. I built something similar and love it, but I'm ready to move on. I've had to replace a couple bearings a couple times, but the function is radically better than the 4x36 that I started with. I solved the tracking issue with electrical tape around the main wheel, which was an 8" poly-clad caster. It sits a little higher on the bench than I would like, so most grinding it at chest level instead of waist level. However, making the tool arm/platen receiver perpendicular to the existing platen was very easy. Have you considered mounting the existing platen/rollers vertically and extending the arms perpendicular to that? That way you could keep the two existing rollers, keeping the tracking from them.

http://www.bladeforums.com/forums/showthread.php/803811-DIY-4x36-into-a-2x72-grinder-conversion
grinder1.jpg
 
Hey Rob, zaph1 has a great use for what you already got. Sometimes you just got to think outside the box and I think zaph1 nailed with that one!
 
Sorry I havent replied sooner guys. I have been away from a computer till tonight.

I agree, the craftsman would be much easier, but I can't really get one right now. Besides, this will be more fun.

Frank, I just hope that trap isn't the main part here.

Greg, The upright will probably be bolted on or welded to a piece that would be welded or bolted on. It till have an arm on it that will have the tracking wheel. The wheel will be attached to a hinge. The hinge will be attached to the arm by one bolt to act as a pivot. There will be a bolt to move the hinge in and out. The whole thing will move left and right by a couple of small bolts. The motor that came with this thing does not have any info on it. It is probably under powered. I do have a couple of motors in a cabinet, one of them is a Dayton, but I'm not sure about rpm or hp right now. There will be a step pulley attached to the end where the shaft comes out.

Justin, you are right about building stuff like this. This is an affliction I enjoy, lol.

Hey Dixieblade, I have been here lurking in the background. Thanks for all the links. I'll check them out. Yeah, I'd rather buy a grinder or get the parts to build it myself, but every time my savings for toys and tools gets larger, it needs to go somewhere else. I hope things for you guys are going well.

Mike and Salem, thanks for the info on welding the cast iron. I may try it on the motor base, but if I need something welded, I'll probably have someone else do it that knows how to do it properly.

Zaph1, thanks for chiming in. I remembered seeing the pic of the one you made, but didn't remember where or who did it.
zaph1 said:
Have you considered mounting the existing platen/rollers vertically and extending the arms perpendicular to that? That way you could keep the two existing rollers, keeping the tracking from them.
Click to expand...
do you mean something like this? With the belt running counter clockwise? Or with the arms out the front, like your, just tilted up on end? That gives me something else to look at. Thanks man!

Thank you everyone for your replies. They all give me things to think about
Rob
Rob.jpg
 
Yes, just like that, mounted vertically and welded in place from one side would be very solid. On most 4x36 belt sanders, the tracking wheels also doubles as a tensioner arm. The tracking on mine comes from the electric tape on the 8" wheel, but it could also be electric tape around the drive wheel. It currently rotates with the belt moving top to bottom, like most commercial grinders do. You could replace the 8" with a standard two wheel flat platen and have the same results. My welding skills have improved considerably since building this one, I used twelve 6-32 set screws around the post to position the 1" tubing inside the 1¼" tubing. This way I can move it in/out to accommodate different size wheels if I wanted. I also replaced the roller bearings with regular bearings in the 8", the roller bearings were crap and overheated quickly. You'll notice the magnets at the top of the 8" that I use to balance it.

All things aside, it is great having a 2x72 grinder, even if it is a flimsy franken-grinder(I love that name)!
 
Hey Rob here is zaph1's post when he built his grinder! I just happen to google 4x 36 grinder and it popped up!
http://www.bladeforums.com/forums/showthread.php/803811-DIY-4x36-into-a-2x72-grinder-conversion

I see where you are headed on this with your drawing and that just might work. You have to work out a few problems I see that could pop up with that design but you may be well on the way to a great franken-grinder for a little amount of money! Listen to what zaph1 said about the bearings. The first bearings I put in my 10" wheel went to do-do shortly after I started using them, but since then I have got some better replacement. One thing about something like this you want to try and not build yourself into a corner. You have to leave provisions for replacing things that will wear out!
 
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