Do not underestimate 1x30" belt grinders

If you have ground a few knives with a file or filing jig, than you already know how much work it is to first prepare the blank for grinding, grind the bevels and then grind the final edge once the knife is heat treated. In particular if you find out that you actually need to thin the blade after HT because you left it too thick before (ask me how I know - see Project #3 for details).

But you probably also already know that a good quality 2x72" belt grinder cost around $2000 (OK, you can get a simpler 2x72" like Grizzly for about $600 in US, but it Europe you are out of luck).

There are however ways in between and about the cheapest option there is is a 1x30" grinder. These seem all to look rather similar and may come with a small (125 mm diameter) integrated disc grinder and cost under $100/100€. The question is - are these any good? The short answer is ... YES

Still clean. The work rest for the disc grinder is not attached yet.

The grinder in question is marketed in Germany under the name Scheppach. The belt grinder has some limited possibility to center the belt (with a small knob on the rear wheel) and that is it. It is even possible to attach a vacuum cleaner hose on the bottom-left side (something that proved very useful alraedy). The exposed part is partially supported with a thin steel plate (barely visible in the photo above) and part is unsupported (slack belt). You can also remove the upped plastic cover and use the upper wheel for grinding curves.

Basic features

The 'platen' of the grinder is a relatively thin L-shaped (attached with 2 screws) piece of steel that flexes relatively a bit under pressure.  If you plan doing some more precise work you will probably want to replace it with something more stable, but  you will have to make it yourself. Still - the platen as it is is usable.

I would also like to mention the speed of the belt. On this machine it is around 13 m/s - that is pretty much spot on - in particular given the low power of the grinder. Important is, it is not super high speed grinder as with just 250W it would be way to easy to stall (which you can still do, but it can be avoided with a little experience)

The work rest on this particular grinder as made out of aluminium and is not particularly strong. It is attached on one side and it does not really allow to be set under an angle.

The 'platen' and the work rest.

The side cover of the belt grinder has an attachment point for a vacuum cleaner. Since I got the Metabo ASA 32 L industrial vacuum cleaner I use it all the time. barely any dust (steel or wood) gets away.

Side cover of the belt grinder.

The disc grinder has a bit more substantial work rest (though still made out of aluminium) that can be adjusted from 45 to 90 degrees. A plastic part can be attached that allows to attach a hose from a vacuum cleaner. This proved VERY efficient in minimising the amount of dust (in particular when grinding wood) that would spread across the workshop.

The translucent  cover of the top wheel can be removed and you can grind some curves around a handle.

From inside

Removing the belt cover you can see the bottom large wheel that transfers the power from the motor to the belt, the top wheel and finally the rear wheel which has an adjustment knob.

This adjustment knob has 2 functions (which would be adjustable separately on a more upscale grinder) It tensions the belt AND it allows for certain left/right adjustments.

Adjustment knob on the rear wheel.

How to set up

To attach and adjust a belt I found the following procedure to work the best:

1. Remove the plastic cover and unscrew the adjustment knob completely.
2. Put a belt on the bottom and back wheel - 1/2 of the width.  Hang the belt loosely on the screw next to the upper wheel.
3. Press with your left hand of the rear wheel and push it against the spring (towards the platen). 
4. Slide the belt on the upper wheel with your right hand.
5. Gently push on the belt from the side to get it fill width on all 3 wheels.
6. Screw the adjustment knob until you see the rear wheel moving (tensioning the belt)
7. Turn on the grinder briefly and see how the belt runs. If it is too far left or right adjust the rear wheel. If it keeps jumping off the wheels on the left irrespectively how much you adjust the rear wheel, than you will need to use a little brute force and push on the frame close to the upper wheel towards the right. I did have to do that. This will affect the belt alignment agains the platen, but it will run well without jumping off the wheels. 
8. Repeat the step 7 gently until you get the belt running stably with the adjustment know around the middle of its range.

Preparing to mount a belt.

Pushing on the rear wheel (once the adjustment knob has been screwed  loose).

Disc grinder side with the vacuum hose attached.
That big green thing in the background is the Metabo vacuum cleaner :)

Belts

The grinder comes with some sort of cheap aluminum oxide belt which will not last much when working with steel. To grind steel you will need to get belts that were designed for such purpose. In general this means to get Zirconia (also called ceramic) belts of some sorts. In Germany there are Klingspor belts available, I have got a few for testing, but I have not been too impressed (part of the reason was the grit - 24 is way too coarse and breaks off the belt easily).

Some really nice belts: from left ro right: 3M Trizat 'gator', Sait 7S #80, Norton Blaze #60 , Sait 7S #240

You basically need (want) 2 types of belts for the start (that is what I have at the moment)

• Ceramic belts (like Norton Blaze or Sait 7S) for bevel grinding or handle shaping. These belts are relatively hard and last a long time
• Softer belts (3M Trizact - 'gator' or 'normal' - these are available in higer grits and are great for removig scratches, or getting around the corners of a handle or a knife heel on a slack part of the belt.

I have also briefly tested Sait 7S and Norton Blaze belts. I have used Sait 7S in 40 grit to profile a blank (after rough cutting with angle grinder) and I have finished 6 blanks with single belt and the belt will do a couple more.

Norton Blaze in 60 grit seem to be the right fit for this grinder - they cat plenty fast (remember - this baby has only 1/3 hp) and seems to last well.

So - what can you do with this baby grinder?

• Profile blanks - this is so much faster than with a file AND i allows you to use a quick and dirty method of cutting your blanks with an angle grinder (the cheapest 'powered way' to do so).
• Grind bevels - there is quite some learning curve - the narrow belt does not make it easy to get even grind and the platen is not quite as sturdy, but it can be done - and it is of course faster than with a file.
• Final-grind bevels after heat treatment (care needs to be taken not to overheat the edge)
• Shape handles - you can use the slack belt part for easier rounding of the blades and the upper wheel for some radius grinding
• Shape bolsters
• Shape your hand-made fixtures and tools (i.e. to take off edges of a file if necessary)
• The little sanding wheel can be used (with some experience) to flatten/square blade steel and handle blocks. You would want larger disc sander for that, but hey, once it is there why not giving it a try.

Weak points

Not evetything is perfect though. With these simple machines you will have hard time to square things up, the 'platen' is rather weak and will flex under too much pressure making keeping constant angle harder. And, obviously, the narrow belt will make it harder to get even grind. But none of these little deficiencies is a show stopper. You have also very limited possibility to set the tension and position of the belt on the grinder.

A few examples

Grinding a bevel on a blade.

Grinding the glued WA handle to rectangular shape.

Flattening the sides of the handle with the disc grinder before final shaping.

Final shaping of the handle with the disc grinder.

Grinding to shape of integral handles (here birch bark handle).

General warning

When using the disc grinder (this one or bigger model) - be careful - if you do not hold the item you are working on firmly and the grinder bites into it (dents it in the process), it will send it flying across your workshop. Happened to me a few times with the WA handle shown above. So be careful and wear your safety gear.

Dust

If you start using the grinder (and in particular the disc grinder) to grind wood, you will find out that it will produce crazy amount of fine wood dust that will get everywhere. I finally broke down and got and industrial vacuum cleaner (Metabo ASA 32 L) which can be attached to simple plastic covers and can directly suck-away good 95% of the dust produced.

In General - steel dust is rather heavy and does not tend to spread quite as much as wooden dust. In particular the disc grinder will tend to fan the fine wooden dust over quite a distance, so using some sort of suction device really helps.

The costs

Let's be honest here - the cost of this little grinder itself will sooner than later be topped by the cost of the grinding belts. Remember - the worse/slower the belt cuts, the faster will the blade heat up as the hot material that is directly in contact with the belt is not being removed and all the work the grinder does is being turned to heat.

You should expect to pay around 2 $/€ per good quality ceramic grinding belt and  more for those awesome 3M Trizact "gator" belts. And you want them.

The vacuum cost me around 150€ (but it also helps to keep the workshop in shape). There are cheaper models for under 100 € that will do the same job.

Summary

The take-aways are:

• This is a little capable machine that will alow you to get decent results and to learn how to use a belt grinder.
• When grinding handle material you may need a vacuum that will keep the dust in check
• Be careful with the disc grinder - it likes to send stuff flying around.
• Get high quality ceramic belts for steel grinding (like Norton Blaze or Sait 7S). Cheap aluminium oxide will last just a fraction of a ceramic belt and is not cost effective.
• The cost of the grinder will be quickly topped by the cost of the belts

Please do not hesitate to ask questions or share your views or ideas :)

My 4 meters squared workshop

Just to give you an idea where all these articles started and why there are always cardboard boxes in the background.

Since we live in an apartment the only viable place for a workshop was on of our basement rooms (yep, we have 2 :) ) each of which is about 2x4 m large. Since we collected quite a collection of cardboard boxes that while taking a lot of space proved very helpful when moving from place to place (something we did several times in past 10 years) , so we decided to keep them. That also means that the space I was able to claim is only about 2x2 m for the knifemaking activities.

Here is a short video just to give you an idea how small a 4 m2 workshop is.

When I decided to start making knives I only had a small box of common tools (hammer, a few low quality files, set of screwdrivers, some allen keys, etc.), Lio-ion powered Metabo hand drill (which is surprisingly powerful) and a smaller (100mm jaws) vise which I originally bought for some smaller/lighter woodworking (activity that did not quite take off) and had it mounted on a piece of wooden board so that I could attach it to a counter in our kitchen (yes, my wife did allow me to do that with some smaller reservations). That basically meant that I had to buy all tools I was going to need for the knifemaking. This proved a little more expensive than I though it will, but hey, that is the case with every hobby :)

This is where it all happens.

The workshop is located inside out basement among with all others.

Obviously the very first thing I needed was a workbench. I got one 92cm tall, 60cm wide and 150cm long (the longest I could fit inside the cellar). It turned out it was not stable enough (for 200€ !?) and had to do some DIY stabilisation on sides. Once attached the workbench became rock solid. Powertools - take it as something to improve.

Lot's of stuff, but you can see the crossed stabilisation bars on the far side of the workbench.

I have then got all the parts for the bevel grinding jig (see my article on that topic for more details), a hack saw, some more files and needle files, safety equipment (3M half mask, gloves, googles).

I soon realised that while not a complete must, a drill press is going to be VERY helpful - what proved to be 100% true. After long consideration I took the plunge for Bosch PBD 40 which turned out to be a great machine for this purpose. It is stable enough to stand without moving around, but still lightweight  enough to move aside if necessary.

The most essential power tool in a knifemaking workshop - the drill press.

What followed was a cutting pad, French curves, small wise for the drill press, rotating base for the bench vise, workshop scissors (robust), drill bits, a log book (a VERY important tool - I find that keeping notes is essential to the process of learning), aluminium jaws (inlays) for the vise so that I do not scratch or damage some materials I will be working on.

Bevel grinding jig made according to the design by Aaron Gough.

The amount of larger and smaller tools kept growing (and I did not even mention materials yet) my workbench was covered with stuff and the amount of cardboard boxes used for storage was growing and I was never able to find what I was looking for.

To at least partially solve this situation I got some small perforated wall whith attachable hooks and holders for some of the tools (files, saws, hammer, grinding belts, etc) and a set of small 'drawers' attached to a wall to keep the smaller items sorted and findable.

The tool wall - facing the workbench.

I also got a metal multi-case (that is mostly used for tools) where I keep my stock of wood for handles, smaller blades and smaller pieces of steel, together with leather working tools. (which are still waiting to be used)

Large metal toolbox that I mostly use to keep handle material, steel and ready-made blades.

Still - large tools and cases are stored under the bench - together with that large vacuum cleaner that helps a LOT to keep the dust from sanding (in particular from wood) to spread across the whole workshop.

Part of the boxes are kept on a small 4 wheel cart which stands outside the cellar when I am working (I store there also all my stuff for my darkroom activities as my other hobby is analogue photograpy). That 3 gren flat plastic cases are used to store metal material for pins and bolsters, fibre mats and leader for sheaths and finally, the sanding paper.

The cart occupies the only free space in the workshop and thus must be removed if one wants to enter :)

Materials

As a proper beginner I have quickly collected a lot more material that I can use in a year. Without the intention to become a steel junkie I have some O1, D2, A2, 80CrV2, 52100, 1.2519, 1.2442 and SC125.  But I just want to play and test. For the future I will probably settle on 2-4 different steels for different purposes.

My 1.2442 steel stock in 3.3 x 60 x 660 mm. I keep it for when I get better in grinding.
It would be a waste to start to use it now.

And the situation is not much better when it comes to handle material. I got about 15 blocks of all possible kind of woods, some scales in wood, micarta and G10 and few more are on the way.

Just a part of my handle material collection.

And of course than there are fibre spacer sheets in different colors, brass and nickel silver for bolsters and pins, leather for sheaths, etc.


The future

I hope to manage to claim the whole room of 8m2 and get more workbench and storage space, so that basic tools have their fixed position and are ready to use. I would also like to get some more tools - in particular a full size belt grinder and full size disc grinder and maybe a buffer - and as of now I have no place for them.

Ideally - a workshop with size of some 20+ m2 would be ideal, but it is not a must.

The king of the workshop :)

Questions ? :)

Project #4 - Birch Bark Handle for a Puukko Blade

Since I have worked on the Projects 1, 2 and 3 more-less in parallel and also had the blades sent for HT I wanted to try something else in the mean time. Already before I started I got a few ready made blades (mostly for puukko knives). So I have decided to take a simple Polar whittler puukko blade and try to make a handle from birch bark. My Iisaki Aito also has a birch bark handle and it proved very comfortable and practical as it offers a great grip.

The Design:

This part was pretty straight forward and I though so will be the execution. But I underestimated all those little details that can go wrong when you do something for the first time :)

Basic components

• Polar carbon 80mm blade with HRC 59
• 5mm thick brass bolsters
• 0.8mm thick fibre spacers
• birch bark
• 1 cm tick piece of stabilized wood

The tools

• hacksaw
• DIY bevel grinding jig & permanent marker
• DIY clamp for the gluing of the handle
• knife, scissors
• bastard (cut #1) and medium (cut #3) files
• needle files (round and flat)
• wood glue (Titebond III), slow curing epoxy (min 60 minute)
• hammer
• sanding paper (120, 180, 240, 320, 400)
• degreasing stuff (acetone or similar) and pure alcohol

Basic parts and tools.

Birch bark

Since one of the most important materials was the birch bark, let's start there. From some youtube videos I had an idea how to clean the bark and how to cut small pieces. I expected to make a lot of mess (and I did), but I did not expect it to be such a hard work. The devil was hidden in the fact, that contrary to knifemakers from Scandinavia who would use fresh birch bark, I could only buy one that was already dry. I actually bought the bark from 2 different sources and got 2 very different types of bark (one apparently older and very thick, the other much thinner with smoother surface)

I started to clean the birch bark with bare hands as I have seen in a video before, but since it was rather hard I put on a gloves. 15 minutes later I was having pain in my both thumbs so I moved to scraping the upper layer of the bark with a knife. This worked better and it looked like I am on the right track.

Cleaning the birch bark with a knife.

Once I was nearly finished with one about A3 sized sheath I noticed that on a side there was a split in the bark - about 1/3 of the total thickness from the surface and it went relatively deep. So I pulled on it and large part of the surface came off in one piece - with a much smoother surface underneath. I realized that I need to remove all that relatively thick layer. That went much faster than scraping the bark with a knife and left me with much cleaner bark.

After the thick upper layer was removed from the bark the underlying bark was much smoother.

So I continued in a similar manner with some more of the bark. It took me in total around 2 hours to clean and cut to pieces bark for the whole handle. Once I had enough cleaned bark I have cut it in 3x4 cm pieces altering the orientation for every other row, so once glued on the handle the orientation of the structure in the bark would be perpendicular in every two subsequent layer. This is recommended for better mechanical stability of the handle.

After that I punched holes (with a leather puncher and 4.5 mm large hole) and tested the pieces on the tang of the knife to avoid problems once I will start gluing.

Bolsters (yes, more than one)

The next logical step was to make a bolster which I decided to cut out of a 5mm thick sheath of brass rather than using some pre-formed one. The requirements are simple - it should have a nice tight fit around the shoulders of the ricasso and the tang of the knife.

To get the cutout for the tang I have drilled 3 holes with a small drill bit (I think it was 3mm as the tang was 3.5mm thick) and then I used first a thin round needle file to connect these holes, followed by a flat needle file to shape the opening to a final fit.

Connecting the drilled holes with a thin needle file.

I did file the shoulders of the blade so that they are lying on the same line (otherwise there would be gaps between the shoulders and the bolster)

Bolster #1:

Here I did the mistake of not preparing the tang properly. The important point is to make sure that the width of the tang at the place where the bolster will sit is the most thick of the whole tang, so that when testing the fit while filing the opening in the bolster you do not get stuck too soon and then have the opening too wide for the final position. I was too fast and the bolster had gaps around the tang.

Bolster #2:

With the fresh experience I was much more careful. I did the opening just as large that I would have to peen the bolster in place (last few mm of the tang). But before I would do that  I wanted to finish the shape and front side of the bolster, as this would not be possible once it wold be in place.

Testing the fit while working on the tang opening.

But since I did not want the bolster to have sharp corners, I decided to invest more time and round the front face.  After about 15 more minutes I was rather happy with the result. No perfectly symmetrical, but I though OK for the first knife. Then I sanded the bolster up to 400 grit which gave it a rather nice matt finish.

Bolster shaped, but not polished/sanded yet.

To get the bolster to its final position I have used a block of wood with a hole drilled in the middle and than a steel pipe and a hammer to peen the bolster in its final position. I started to get a good feel about this project :)

Peening the bolster in the final position

However that did not last long - first check showed a very obvious mistake I did. When rounding the front face of the bolster I did not measure how wide the blade was (both on the spine and choil side) and got a really bad looking result.

Obvious mistake - the heel of the knife is sticking out after I rounded the bolster.

Bolster #3

With the lessons learned from first 2 bolsters I decided to make one more. I made it a little larger so that I would not run into same problems as with the bolster #2. I also went with much less rounding this time. I also filed the opening on the bolster a littler large on the back side as this would make the peening a little easier.

Bolster #3 was designed a little larger than #2

Drilling the holes.

Filing the tang opening.

Once I got a good fit I started to shape the bolsters.

Left to right: Bolster #1, #2 and #3

The birch bark handle

Once the bolster #3 was in place I could continue with the handle. Before I would start with glueing I would degrease the tang and the bolster. To be on the safe side I used a 5 minute epoxy and filled in the small void between the bolster and the tang. Once that cured I could finally proceed with the handle.

Before I started I made a simple clamp from 3 pieces of wood and two 50 cm long threaded rods (10mm size) and some screws.

Blade with bolster in blade in the clamp ready for the gluing of the handle.

Before I continued I have used 2 needle files to keep the pieces of bark organized and in the right order.

Ready for gluing.

I have used 2 different glues for gluing. Titebond III (II would be also fine) between the birch bark pieces and slow cure (90 min) epoxy to fill the void between the bark and the tang. It was a rather messy process. Once I was nearly finished it turned out that I have too few birch bark pieces prepared. I have simply clamped what I got and let it cure until the next day. I would then prepare a few more and finish the gluing.

Note: The knife handle could actually be made completely without glue. Just stack all the pieces, put on the the end cap and peen the tang over. Then take the knife and put in an oven set to 80 - 100 °C (cca 176 - 212 F) for half an hour. At this temperature the birch bark will release its natural tar that after cooling will seal the bark. You do not need to worry about messing the heat treatment of the blade as this temperature is too low for that. You can find more details HERE I will try that approach next time.

To give the knife a little spin I added ca 1cm thick piece of stabilized wood (I had some left overs) and on top a brass end cap.

Important - before fitting the end cap I would file the end of the tang (which is not hardened and this easy to file or saw) to round shape such that it would just fine the hole drilled in the brass end cap. Later once the glue cured the tang will be cut so that just a few mm stick out and mushroomed with a hammer to secure the end cap. Later after sanding the end of the handle it turned out that I did not do a particularly great job with the peening, but since the handle was also glued with epoxy it will hold well.

Handle curing after all parts were glued.

I have put a piece of plastic foil between the edd-cap and the vise.

Once the handle was cured I have proceeded with sanding it to shape. I used my brand new 1x30" belt sander and 40 grit Klingspor belt. Since the birch bark is rather a soft material this was proceeding rather fast, but the fine, light dust was everywhere. It was so bad, that I actually stopped sanding and only continued once I got an industrial vacuum cleaner that I attached directly to the belt sander which improved the situation dramatically.

Just few minutes of sanding - still a lot of material to remove, but the dust was EVERYWHERE.

So, once the vacuum cleaner was attached I have continued to send the handle to shape. I have used Norton Blze 60 grit (mainly because I was lazy to swap belts after I was grinding bevels of a different knife). It was a little slower, but I did not want to hurry too much as once you grind too much material away, you can not put it back. I was checking on the process continuously - comparing to the handle of my Aito and simply taking the handle in my hand to see whether it offers a comfortable grip.

In particular I was careful around the bolsters. These are made from brass which has excellent heat transfer abilities and so could yield overheating that part of the handle and damage the Epoxy. Also - grinding too fast or too hard could yield uneven transition between the hard brass and soft birch bark, since the birch bark is much softer than the brass.

In total it took me around 90 minutes to ground the blade to shape.  Since the handle has a simple shape (oval in cross section and barrel-like profile) I kept sanding the all sides and tested the handle in my hand until it felt right. Had I not tested it regularly I would have probably ended up with a handle that would be too large. I kept sanding with the #60 belt until I was happy with the shape. Then I rounded the most 'corners' that were left and with nearly zero pressure put a uniform finish on the bolsters.

Vacuum cleaner is attache - the sanding may continue.

Slowly getting closer to the final shape.

Handle ground to shape and carefully smoothed out with the #60 grit belt.  (I used different belt than the one shown)

Handle finishing.

Once the handle was shaped with #60 belt I continued with Sait 7S #120 and with the smooth & soft 3M Trizact A45 (cca grit #400). This was all very light work - especially around the bolsters. I have rounded the butt a little more and flat sanded the bottom of the handle on every belt to get a uniform finish. I have just touched up the edges of the bolster so that it would not feel sharp in hand.

Once the sanding was done I gave the handle 2 coats with Tung oil which gave the handle a very nice feel and lovely contrast. Seems like the Tung oil works well with the birch bark.

First coat with Tung oil.

Lessons learned

Again - quite a few mistakes and little things that I picked along the way of this project:

• Do not hurry when making the bolster. Thin the tang such that it slightly tapers (left/right and top/bottom) - that will allow you to get a tight fit and minimize the risk of voids between the tang and the bolster.
• Make the bolster a few mm larger in all direction to have enough material for the taper.
• Before you start gluing the handle have EVERYTHING prepared and clear your bench so you minimize risk of tipping things over and such. 
• Use slow cure epoxy - in particular if you use 2 types of glue at the same time, it will take you easily 30+ minutes to assemble the handle and you do not want to put yourself under pressure.
• If something goes wrong mid-way - do not worry. Clamp the part you have done as if the handle was finished, let it cure till the next day and then continue. Happened to me and you can not see it on the result.
• Before you will start finish sanding the handle - test the abrasives/belts you plan to use. Some will loose some grain when fresh and that may get caught in the soft birch bark. You do not need much grinding power, so do not worry to use belts that are partially worn out as those are less likely to 'stain' the handle.
• Go really slow when finish-sanding the handle. Once you got up to about #240 grit use some soft fine belt (the 3M Tricazt series is excellent) - that will make it easier to get smooth finish on the bolster.
• Use some sort of oil on the bark handle. Tung oil worked nicely, but other would certainly do. You could as well use a mix of mineral oil and bee's wax (this mixture is often called 'board butter') and re-apply if the handle starts to feel dry.

Finished knife

The fit of the tang is not quite perfect - there is a little gap.

Next to my trusty Iisakki Aito.