Thread: Building your own grinder: cheap and easy

I got the idea for this grinder when I was working on a 7 day set that needed regrinding. I did the first one by hand, but it was a lot of work because of all the damage. the thought of doing 6 more like that was not appealing so I went looking for something better that would not break the bank.
I finally came up with an electrical sander costing all of 30 dollars, and easy to make.

This is one of those e-z sharp appliances that you can find in many hardware stores. These things are advertised as wet grinders, but they are worthless, and often not even trued. I've tried using the as wet grinder for de-pitting a wedge, and they suck. But luckily, you can turn them into something useful.

the first step is to remove the water resevoir. This is not necessary if there is plenty of room between the stone and the sides / bottom of the reservoir, but even then it is more convenient.
As you can see, this is a high precision job, meticulously executed with a hacksaw and a pair of pliers



The next step is to coat the stone with double sided tape. don't worry too much about any hairline gaps theat might be left they won't make any difference.



When that is done, you remove the coating of the tape, and fix a strip of rubber over the tape. The strip is the same width as the stone.
The purpose of this ruber is to make sure that the sandpaper is cushioned, and that any minor bumps in the stone do not cause scratches when grinding. The stone on this thing is bumpy and uneven (after all, it was cheap) so this is really needed.



On top of that you put tape. Go at least twice or thrice around the rubber band with 1 continuous piece of tape. This is to make sure the rubber stays on, and to provide a flat and stable surface to fix the sandpaper to.



Now it is time to fix the sandpaper. you can do that by putting small patches of double sided tape on top of the black tape. Use only small patches so that it is easy to replace the sandpaper. And if the tape becomes rumpled after a while, it too can easily be replaced.



And on that double sided tape you can mount the sandpaper. whether you need 1 or 2 strips depends on the length of paper that you have, but be sure that there is a bit of an overlap, and make sure that the overlap is in the right direction.



And voila: here you have a very cheap grinder that will do a reasonable job. I restored that entire 7 day set with it, and you can see the results here:
http://straightrazorpalace.com/galle...7-day-set.html

It died pretty much immediatly when that set was done. The gearbox was made of plastic cogwheels, and I had accidentally run the motor into its thermal protection a couple of times.

The grinder should only be used in 20 - 30 minute intervals, and then given an hour at least to cool off. It will depend on the way the grinder is built, but for 30$ or les, you cannot expect much. It had thermal protection, but after I used it for an hour+ and the protection kicked in for the first time, it lost a significant amount of torque. I suspect I shorted out a good number of coils.

Also, it pays to use good sandpaper. Don't use wet / dry because it clogs up faster if used dry then plain dry paper. I found aluminium oxide paper to be excellent. silicon carbide might be better still, but I haven't tried it yet.

This is by no means an equal alternative to a Bader or KMG belt grinder. Grinding pitting damage from a wedge will take some time. But at least the amount of time will be reasonable, and you won't get a tennis elbow in the process.

Great idea, I like this kind of thinking.

Charlie

I love the enginuity of the guys on this site - and proves once again that necessity is the mother of invention!

Very nicely done, Bruno - sorry to hear it crapped out on you at the end though. Any plans on building another grinder from a different motor/set of plans?

Mark

I got this one for free. I already had one, but I tried this one first because it was the crappiest of the 2.
I have since converted the other one to a grinder as well, and it still works fine. I now take care not to use it for more than 30 minutes at a time. So far so good.

Our old washing machine is standing in my garage with the idea of hooking it up there. But I am thinking of taking out the vari-speed motor and building myself a real grinder.
The plans for a real grinder are stickied in the Forge, but so far I haven't had the time to really look into it.
Maybe somewhere later this year.

This one is dirt cheap, and you can build it in less than an evening.

I think your grinder was a real grinder. The seven day set you did looked really good. I think that tools used for your avocation need not be the latest and greatest. As long as they make your hobby more enjoyable, that is all that matters. If you were depending on the grinder to earn money and put food on the table it would be a different story. I like to tinker and figure out different ways to get things done with what I have. I like hearing and seeing other people’s ideas and contraptions.

And yes Rube Goldberg is a hero of mine.



Charlie

If there is a harbor frieght near by check em out,they have buffers and grinders under 50$ and there good for the money. I have a buffer I paid 47$ has the extended shafts so your blades and hands arent all in the grinder. For the money its great they have alot of sales thats when to buy. They have a web sight too.http://search.harborfreight.com/cpis...ffer&Submit=Go

bruno, you rock dude!! you gave me some inspiration and i have since made something that works similar to what you are doing here. i will come back and try to post up some pics to show you my set up. between you, toxik, spazola, kenrup, i have learned much on making do with what you have. thank you guys for all that you do for us to inspire us.

vgod

That's great! I did a similar thing, but with a drill as the motor & a bit more labour intensive to get similar results.
Firstly i used a router with an adjustable jig to cut perfect circles from ply. The great thing is that you can adjust the size so that they fit the grind of individual razors & keep adding the ply discs till it's as wide as you want.
I fitted a large bolt through the centre & clamped it in place with a nut & washer.
The bolt extends one side to allow it to be fitted into a chuck.
The disc gets wrapped with foamy double sided tape, to provide a cushion & hold the sand paper.
Drill goes in a vice & you're away, at last!
The razor shown was the one that the sander was made to fit & is a bit of a wedge.
Hope this is not classed as a hijack!

Originally Posted by ben.mid

Firstly i used a router with an adjustable jig to cut perfect circles from ply. The great thing is that you can adjust the size so that they fit the grind of individual razors & keep adding the ply discs till it's as wide as you want. That's exactly what I was looking for! A method to cut some perfect circles and have adjustable sizes. I have read of that router device before but it did not come to mind. Now I can use that 1.5 HP router of mine, now to find the device.
I fitted a large bolt through the centre & clamped it in place with a nut & washer. I like the idea of using a variable speed drill.
The bolt extends one side to allow it to be fitted into a chuck.
The disc gets wrapped with foamy double sided tape, to provide a cushion & hold the sand paper.
Drill goes in a vice & you're away, at last!
The razor shown was the one that the sander was made to fit & is a bit of a wedge.
Hope this is not classed as a hijack!

Thanks a bunch for posting this! I need to make more wheels for my grinders and this is a great solution.

Many thanks!

Thanks Randy,
You can make the guide. I used threaded bar that fit's through the channels that hold the fence. I flattened one end & drilled a hole to allow a screw through. You just screw this to the board & it becomes the centre of your circle with the router revolving around that point. With long enough bar you can make virtually any size. It helps if you fix the board you're cutting down, both within & outside the disc to be removed. My drill has a speed sensitive trigger, so i use a zip tie, or rubber band to determine speed. That helps with keeping the heat generated to a minimum.