A new knife grinder

[W.R.Buchanan]

OK that should be more than enough tracking adjustment. I doubt mine has been adjusted more than 1/8" total in it's entire life of 30+ years. It doesn't take much to move the belt.

I highly recommend that you spin the belt by hand the first time to make sure the belt is tracking on the pulleys. If you start the machine and it is not tracking on the wheels is will destroy the belt in an instant and throw the whole mess in your face. BTDT.

Randy

[knifemaker]

Never and I mean never stand in front of the belt when you start up any 2x72 grinder. Most times the belt will come apart at start up and you do not want those belt fragments hitting your face. So far in 10 years of knife making I have never encountered a belt blow up, but I still stand to the side when starting up the Bader111 knife grinder.

[Von Gruff]

Do the 72in belts have a direction of travel marked on them like the smaller 36in belts do?

[knifemaker]

95% of them do have arrows showing direction of travel. Some of the finer grit belts do not. It may depend on what type of connecting joint they have, a guess on my part.

[W.R.Buchanan]

I have had numerous belts blow up at start up over the years. Lots of times the belt is old or has a edge that has been frayed or sometimes the splice gives up. I any event it usually happens during start up and that's why you stand out of the way.

Like so many other things, all it takes is getting slapped in the chops once and you'll learn.

Some belts are directional and some aren't. It depends on the splice and how it's made. Butt spliced belts usually aren't directional. Lap spliced belts are. You don't want lap spliced belts because they have a bump in them that gets annoying in about 3 seconds.

Obviously if the belt has arrows on it,,, it's directional.

One other little fine point. If you look at the pic of my grinder you see there is a little deflector shield over the top pulley. The eblt will carry grinding swarf along with it and when the belt changes direction,,, like over a pulley,,, it will throw the stuff off. Like in your face.

That little aluminum shield peels the vast majority off before it ends up in your eyes, ears, nose and mouth or any other exposed orifice. Grinding Knife Blades is dirty work and is one of the reasons I don't do it very often..

Randy

[Von Gruff]

Again I have to reiterate for those who do not read the posts that already been made, and as mentioned in post #15 I have been using belt grinders for near 35 years and belt sanders (with 12 foot long belts) since the 60's and to be continually offered advice suited to a someone who has never used a belt grinder or sander is a bit condescending

[W.R.Buchanan]

Sorry no intention to condescend,, just offering up info that others might not know. I figure if you've been using these for 35 years you have some idea what is going on, however these fine points are not widely known or obvious and someone coming along without that experience might benefit.

Sorry if I offended I have nothing but the highest regard for your work. Only trying to add content to the thread.

Randy

[Von Gruff]

Have had some good progress with a couple of hours at the engineers yesterday. He turned the heavy collar of the end of the shaft and lengthened the turned portion to take the drive wheel, then turned and threaded the other end to take the disc grinder and leather strop.
With a bit of welding done it is at the stage now that it just requires the wheels and a couple of more bolts to be ready to go.
The disc grinder and with it being 375mm (14 3/4 in) in dia with a 40 grit disc it will be a great asset

The smaller disc (doubled 3/4 ply) has a leather strap glued round the edge and loaded with green stropping compound and having already tried it on a knife I am really pleased with how it works.

On the belt side, there is the platen plate that needs the two idler wheels to complete. The tracking wheel is also needed but these should all be here in a week.

The 300mm (12 in) contact wheel


The small wheel just needs the idler wheel for the lower position and I will have the means to grind the finger curve on the front of the knife handles.

The tool head stand will get a length of 3x2 (75x50) fixed on the top with short lengths of 3 in (75mm) down pipe screwed to it to hold the variety of belts

[EMC45]

Super cool!

[Southern Son]

Where did you get the 300mm contact wheel?

[Von Gruff]

China. Great prices (compared to the US sites) with excellent shipping times

http://www.aliexpress.com/wholesale?...crowned+wheels

http://www.aliexpress.com/premium/be...ls&blanktest=8

Wasn't able to get the idler wheels there though.

[Von Gruff]

Another little knife clamp made today
A length of 2x2 box, a couple of short lengths of 1 1/2x1/4, a hinge, 2 pins, 2 nuts and bolts and a bit of shoe leather were all that was needed.


The leather clad gripping arms on top of the box to show how they work

Great for either end of the knife whether vertical

or horozontal

And of course it is invaluable for polishing (or any other work) on the blade

[EMC45]

I'm still very impressed.

[Von Gruff]

Most of the wheels and a few of the belts I had been waiting for arrived so there was a little more progress on the grinder today.
It did take a little while to set up to make sure all the wheels were in the same plane from the edge of the base and thata required a spacing with washers to get it all right but eventually I ran the belt and it tracked true so I was a bit pleased.

Having it running true I crowned the drive wheel the simplets way by glueing a 1/4 in strip light leather round the center point of where the belt ran then covering it with another strip of 7/8 in to effect a rudimentary crown that does work well.

Getting the platen plate wheels sorted was next but that now tracks to the same position on the tracking wheel as the big wheel so it all seems to be working as intended.


There is a replacable platen plate that is bolted to the angle iron backer so that it can be changed out as and when it inevitably developes wear patterns.

There is only the first few belts that have arrrived at the finer end of the spectrum from 120grit to 600 but there is a number of 40 and 60 grit on the way along with another set of idler wheels, one of which will be for the lower part of the small 1 inch wheel for doing the front curve on the knife handles.
I gave the disc grinder a run and it is all that I hoped it would be so along with the leather stropping wheel I think this is all about ready to be put to work.

[Buck Neck It]

What is the rpm of the motor you are using?

Good idea using an old table saw as the base. "Contractor" grade table saws seem to have no value where I live. There was one at the dump last week, I am going to have to fish it out.

My wife will kill me for starting another project.

[Von Gruff]

I believe it is 1450rpm or so the engineer said when I was there last week and running from the 1 1/2 in pulley on the outshaft through a 6 in pulley to slow it down and then to the 4 1/4 in drive wheel. The belt feels like it is running at about the right speed so it will grind nicely.

[Von Gruff]

Another little part of the project came together today with the plunge line jig done although it still needs hardened yet.
The end of a file I had made a knife from with some die and a couple of scribe lines marked in

A bit of cutting and I have the required parts.

A while later with a bit of shortening and a pair of holes so I could grind it all paralell and it bolts onto the knife to define the plunge line. It will ensure that both sides are exactly the same.


This is only part of the jig as there is a piece of angle alluminium with a hinged base plate that this little plunge line jig fits into and clamps onto so the bevel grinds are both exactly the same as well.

[Von Gruff]

The second part of the grinding jig was completed today. A foot length of 3x3x1/4 in alluminium and a piece of flat 3x1/4 in along with a length of piano hinge and a couple of bolts. I used aluminium for its lightness and that it will act as a heat sink but can all be dunked in the water bath to keep things cool without the worry of rust.

With the flat piece hinged to the angle I cut three areas to take the jig. For short knives I can work out from the end cutout

You can see from this shot that the bolts screw the angle up from the base at the rear to give the required angle for the bevel grind. The bolts make a handle to hold and guid the jig with.

This is an already ground blank in the jig with the square showing where the belt would run

Knives with mid length blades can be done from the center position


And long blades can be done from each end but facing inward rather than outward for the short blades

[Kalahe]

All the knifemaker's that I know will have at least one 2x72, most have several. 2" x 72" belts is the normal....easy to find, ecomomical, many different types. When you get into the other size belts you get more into hobby machines, you will not have so many different types of belts to choose from. Although you can buy 1" wheels for most grinders. The KM2 especially.
You can always split a 2" belt if you need a narrower belt. Take a knife point and pierce the belt, just a small cut, and then pull it apart. The small cut will follow all the way around the belt. You can have any width you wish. A 1/4" belt will run on a 2" wide wheel. To slack belt, on contoured handles and guards.
I agree with dave.....if funds permit, go with a Variable.....If you don't have the funds, sell one of your rifles.....you can always buy another rifle with the quality work you will be doing using the variable speed.
When you consider a grinder, ask yourself the question "What are you going to use it to do. Grinders come in front drive, and rear drive.
The KM2 that Dave reccomends has a rear drive. I have one and love it, wheels are easy to change.....but if you want to use your grinder to buff then you need a front drive. I have a Burrking, that can double as a buffer.
Another very good versatile grinder is a Wilton Square Wheel. Very similiar to the Bader KM2..... I have one that is an Olympic.....Wilton bought out Olympic https://mechanicguides.com/best-belt-grinders/ and called it a Square Wheel....mine is Really really OLD, and is stiIl running good.
I started out with home made grinders, and have owned all the major brands. If I could only have one grinder, it would probably be the Bader KM2 WITH VARIBLE SPEED. IMHO.....DON'T BUY
However, for fine finish work, you can't beat the Burrking. It runs very
smooth.
BTW, If you buy the KM2, you can build most of the extra accessories yourself. You will never own just one grinder. They are like .22 rifles, or Sumphen like that.
One other thing, of the thousands of things everyone here could tell you ...
Here's a couple things to think about.....If your going to hollow grind, and take the grind to the spine, save yourself some money and head aches and go with a 12" wheel. Semi-soft (durometer) wheel.... Hard serrated wheels are for profiling, rough removal.....the softer the wheel, the smoother the cut, use a soft wheel for final finish.
If your going to flat grind, then a 8" hard serrated wheel will be fine for profiling and rough grinding. Hope this helps
On YouTube there are a lot of interesting videos...

[rking22]

Timely resurrection, Im in the process of buildinv one right now. Using a treadmill motor with "dimmer" and bridge diode for variable speed. Phyzical design very like Von Gruff's project. My drive wheel is turned from alum and bored for the motor flywheel. 3.82 dia lets the tach i got from china display ft/min of belt speed. Got all the parts just gotta put it together.