Bolt Together 2 X 72 Belt Grinder

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Introduction: Bolt Together 2 X 72 Belt Grinder

I have been wanting a 2 x 72 belt grinder ever since I started making knives on my wimpy 4 x 36 belt sander. After looking around at some designs I figured I could probably make one myself. I had access to our scrap bin at work that often had square tubing and small chunks of flat stock but I didn't have access to a welder. This led me to design a belt grinder that was similar to many of the welded designs I saw but would be bolted together rather than welded. This also had the advantage that if one of the pieces broke or I messed up on it while making it then all I had to do was unbolt it and make a new one.

Here are some sites that I referenced when designing this. They have additional information that I may not include that may help you out.

https://www.instructables.com/id/2X72-Belt-Grinder...

http://dcknives.blogspot.com/p/2-x-72-belt-grinder...

http://dcknives.blogspot.com/p/budget-2-x-72-belt-...

Step 1: Drawings and Models

Below I have included some drawings and models that should hopefully help you with the dimensions and hole layouts. I included the drawings as pdf's and the .step file for the entire assembly so you can see how it all fits together. If you do not have a 3D modeling software I have also included a 3D pdf that will anyone with adobe acrobat (its free) to be able to view the assembly as well.

Note: While making this I made some changes and these drawings and models are not 100% the same as what I show being made. I will address the changes in each step as they differ from the drawings.

Material List:

2in x 2in square tubing in the following lengths:

One 5in long tube

Two 10in long tubes

One 11in long tube

1.5in x 1.5in square tubing in the following lengths:

One 7in long tube

One 17in long tube

One 12in long tube

Two pieces 2in x 6.5in x .25in (this can be thinner but it is nice if it is thicker because it will be threaded)

Two pieces 4in x 4in x .125 (this can be thicker if you want but not any thinner)

Four 2in long pieces of 2in angle iron

One piece at least 2.5in x 8in x .25in for the tool rest

One piece 2in x 2in x .25in (I made mine more around 2in x 4in x .25in which you will see later)

One piece 1.5in x 1.1in x .375in for one half of the hinge

One piece 2in x 2in x .375in for the other half of the hinge

Parts list:

Lots of bolts (each step will show the bolts you need, most are 3/8in bolts but they don't have to be)

Lots of lock nuts (these are important as this vibrates a lot and you don't want it coming apart)

Two adjustable position handles (I used these 3/8 x 1 1/4 ones)

Flat platen tool (I bought this one but the second link I provided has the plans for one if you can make it)

Guide, tracking, and drive wheels (I bought mine form here but the third link shows how you can make your own)

A gas spring (I used a 7in 100N/22lb spring from amazon but it is no longer available)

A handle (I turned a 2 x 2 piece of wood into a handle but you could buy whatever you want)

A motor (This completely depends on what you have or the power you want, I have a 1hp motor with a vfd to provide variable speed control)

Step 2: Making and Attaching the Front Plate

I forgot to take pictures before I drilled all of the holes but I tried to show them in a way that would explain the step by step approach that I took when making this.

First you need to cut all 4 of the 2in square tubing to the required lengths. For the two 10in tubes you will want to file away the weld seam because this is where the 1.5in tubes will be inserted and that seam will make it difficult. These tubes have a 3/16in wall thickness. It is important to have thicker walls on these because the 1.5in tubes fit into them and you want as small of a gap as possible.

The next part that I show was originally designed to be 2in x 2in but I ended up making it 4in long because as you will see later on I needed to room so that I could have a surface to mount the gas spring to. When making this part you need a drill press because you are drilling all the way through a 2in part and unless you are way better at free hand drilling than I am it is near impossible to drill through this evenly. I drilled these to allow a 1/4in bolt to fit all the way through this and the two side plates. Many of these holes can be drilled slightly larger than the bolt so that even if you are a little off then it can still be assembled. when you tighten everything down it will be tight enough that nothing will move.

Then you will want to drill the holes on the two side plates. One plate will be drilled to have two 3/8 in threaded holes in it and the other I decided to put two 1/4in threaded holes in it even though I didn't have them on the drawing. These 1/4in bolts were used to keep these plates fixed to the two 10in tubes. Then you will put a 3/8in hole in the bottom that will hold the front leg in place.

Assemble as shown and then drill the hole in the front leg, this tube also had a 3/16in wall thickness, and bolt it together. once this is bolted together then you will want to use the holes on the plates as guides on where to drill the holes on the tubes below them. Then you tap the holes and add the bolts and handles. If you need to learn how to tap a hole it is included in the classes they offer on here. Just go slow as I broke a tap while making this.

Step 3: Making and Attaching the Rear Plate

Now to work on the back side. For the 11in tube you will need to cut out the top to allow the top arm to be able to fit into it. This tube only had a 1/8in wall thickness due to the material I had available but it is not as important as on the two 10in tubes.

Then you will need to create the two 4in x 4in plates. These hold the back and together. It worked best be me to drill the top hole in the vertical 11in tube and then put the bolt through and then use the plate to mark the second holes location. I did the same thing for the next two holes through the other tubes. Then you just bolt it all together.

Step 4: Making the Hinge for the Tracking Wheel

To be able to adjust the tracking of the belt, the tracking wheel needed to be mounted onto a hinge. I decided to make my own hinge because I had a small desktop mill available and the steel to make it. This hinge just needs to be able to attach to the upper arm and the other half of the hinge has to be able to hold the bolt that the tracking wheel spins on.

Step 5: Making the Upper Arm

To make the upper arm you will need the 7in long piece of 1.5in tube. The 1.5in tubes I had all had a 3/16in wall thickness. This will fit into the back 11in tube where the slot was cut out. The holes in the back are where a bolt will go through to allow it to rotate up and down. When fully assembled this arm is pushed up by the gas spring and provides the tension on the belt. You will then need to drill the holes for the hinge and handle.

Because there is a gap when this is inserted into the 11in tube I bought some nylon spacers ans sanded them down so that they would take up the gap between these two parts.

For my handle I just turned a 4in piece of 2x2 wood that I had laying around and drilled a hole through it so I could run a 1/4in bolt through to attach it to the tube. You can buy a handle or make one however you want. it is just needed to pull down on the arm when changing belts.

Note: I talk about it in the trouble shooting section but I would recommend making the arm a couple inched longer and moving the handle up further allowing for the addition of a tracking adjustment knob.

Step 6: Making the Feet

To be able to mount this to a surface it needed some feet. I had access to some 2in angle iron so that is what I made these out of. They are all 2in wide and have a 3/8in hole on each face. one hole to mount to the belt grinder and one to bolt into the table I mount it on.

Step 7: Making the Tool Rest

To make a tool rest for this I needed a long piece of 1.5in tubing to insert into the lower of the two 10in tubes. I determined this needed to be about 17in in length to sit in the right location. I then found a good sized piece of flat stock and drilled and tapped two holes and then used those holes as guides to drill the holes in the 1.5in tube. I then fed two bolts in through the bottom and ground them so that they would not stick up out of the plate.

Note: When figuring out where to drill the holes on the flat stock it is important to note where the belt will be and center your plate about that point so that you have that same amount of tool rest to either side of the belt. Unless you want it uneven, in that case do it however you want.

Step 8: Making the Flat Platen Tool Arm

To make the other tool arm you will need to know what you plan on mounting to it. I was going to mount a flat platen to it so I used the hole locations from that to determine where I needed to drill my holes. If you use a different mount than the one I used you will need to determine where your holes will need to be accordingly. You can make multiple arms to accommodate additional things like a large or small contact wheel. I found that 12in was the length needed for the flat plated attachment I used but you may need something longer or shorter depending on what you plan on attaching to it.

Step 9: Attaching the Gas Spring for Belt Tension

I determined I needed a 7in long gas spring to keep the upper arm at the angle I wanted. This is why I ended up making the top of the front plate 4in long instead of 2. I needed room to mount the gas spring. This was simply just figuring out where I wanted it to be positioned and then drilling and tapping the holes for the screws to hold it in place.

Note: be careful when drilling the holes in the plate so that you don't drill into where the other bolts are in that plate already.

Step 10: Trouble Shooting

There were a couple things that I ran into that I would like to make note of to help you in setting up your grinder.

  1. Make sure all the wheels are aligned correctly. I had to drill the holes in the top arm bigger for the hinge because it had enough wiggle that the weight of the tracking wheel and tension of the belt bulled it down too much. I just made the holes bigger and twisted the hinge some more before bolting it down. I also had to do some troubleshooting to make sure the motor was aligned correctly so that the drive wheel was in the correct alignment with the rest of the wheels.
  2. The tracking wheel will need to be pushed out some to track correctly. I didn't fully understand this part of the grinder when designing it but to adjust the tracking of the belt the tracking wheel will need to be pivoted on the hinge either in or out to adjust the belt. I did not add this kind of feature when I designed this but I would suggest making the upper arm longer and mounting the handle at the top making room for a handle with a threaded rod to be added that can be twisted to push the tracking wheel in or out. For now I just drilled a hole in the hinge and added a threaded stud that can be twisted to push it in or out but it is a pain to adjust.
  3. There may be clearance between the tool arms and the 10in tubes they go into. I got some 1/16in thick nylon sheets that I cut into strips to fill the space between those parts to prevent the tool arms from being able to wiggle due to the clearance between them.

Step 11: Fully Armed and Operational Belt Grinder

Your grinder is now complete and all you need to do is add a motor, set it all up, and you are ready to grind away.

If you want you can get some 1.5in square tube plugs to cap the exposed ends of the 1.5 tubes just to clean it up. I plan on adding those and painting it next year when it warms up again.

Thank you for checking this out. If you have any questions, comments, or improvement suggestions please let me know.

Step 12: Updated Design

It took me long enough but I finally got around to updating the upper arm on my grinder. As you can see from the pictures, I made a new tube that is about 5 inches longer so that I could move the handle to the end and make room for a bolt that would allow me to adjust the tracking wheel more easily. I just plan on 3D printing a knob to fit on to the end of the bolt to make it so I can turn it by hand instead of with a wrench.

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83 Comments

0
Danny1972
Danny1972

5 weeks ago

Thank you so much. I have a 2.25HP motor with VFD (no name China) coming in February. This design looks perfect for my needs. Being a rookie knife maker I really do not want to spend the $700 and up from a grinder (WITHOUT a motor) you have to spend in Canada.
May I ask how you made the tracking knob?
Thanks again
Danny

0
IJustLikeMakingThings
IJustLikeMakingThings

Reply 5 weeks ago

My tracking knob is just a 1/4-20 bolt that has a 3d printed knob on the end to make it easier to turn. I had to thread the hole on one side of the upper arm so that screwing in the bolt causes the tracking wheel is pivoted away from the arm. you should be able to buy bolts with a knob on them already or just use a bolt. hope that helps.

0
Danny1972
Danny1972

Reply 5 weeks ago

Great, thank you

0
KevinW145
KevinW145

2 months ago

Thank you for sharing this. I appreciate the design and the level of effort you put into this post. I'm going to use your design as a template. However, since I'm a welder, I'll use welded joints where applicable. I want to be able to lay the grinder horizontal also, so, I'll make the base changes for that. Stay tuned, and I'll share my adaption. Thank you brother.

0
IJustLikeMakingThings
IJustLikeMakingThings

Reply 2 months ago

I look forward to seeing yours when you make it. Some day I hope to get a welder so I can do the same. Adding the tilt function sounds like a great idea, I may look into adding that as well.

0
Ollio_
Ollio_

4 months ago

Hey man! Im thinking of building this in the near future and im wondering around how much it cost you? I am new to knife making and have been working completely by hand. While researching what cheap ish grinder to buy i came across this and thought why not build a 2x72? (As long as it costs less to do so) :)

0
IJustLikeMakingThings
IJustLikeMakingThings

Reply 4 months ago

That is a difficult question to answer because there are a lot of variables that have a large impact on the price. I believe I spent around $500 - $600 on mine but it's been a while so I can't be 100% sure. And I got most of my material for free.
Cost will depend greatly on these factors:
Material, any access to scrap or a cheap supplier can reduce the cost.
Motor, the size, brand, and the ability to find one used. Used would be the cheapest route. also less hp is cheaper but not as powerful. but it can be upgraded later. Off brand Chinese are also cheaper than name brand.
Speed Control, using a speed control like I did will add about $200. Not using one is significantly cheaper.
Wheels, if you make or use alternative wheels it will reduce the cost.
If money is a concern, I would see what you can salvage that would work and check out scrap yards. if any are even open right now.
With most of these grinders, it is more of a template, depending on what you have available or how much you want to spend can change the design and performance. Look at the links I have at the beginning if you haven't, there are some alternatives that may be more cost effective or options that you can implement into yours to keep the price lower.
I'm sorry I can't give you a solid answer but hopefully this helped.

0
Ollio_
Ollio_

Reply 4 months ago

Yes this helps a lot! I love that your still answering questions to this day! Thank you

0
IJustLikeMakingThings
IJustLikeMakingThings

Reply 4 months ago

I'm glad. I try to do my best and answer all questions that I can. Luckily for you I had answered this question before because I wouldn't have had any clue to the cost anymore.

0
scottpaul2005
scottpaul2005

Question 6 months ago

Okay I was wondering what exact Motor did you use and the wheels

0
IJustLikeMakingThings
IJustLikeMakingThings

Answer 6 months ago

I bought the wheels from here: http://www.ebaystores.com/oregonblademaker
I bought the aluminum tracking wheel, drive wheel, and D-backing plate with wheels They also have a good selection of other parts and accessories for anything that you can't/don't want to make.

The Motor I used was this one: https://www.amazon.com/gp/product/B007IVS14Q/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=
I chose this one based off what the vfd could handle. There are also other versions depending on your need.

0
Mario Tin-ga
Mario Tin-ga

Question 9 months ago on Step 1

Hi, I wonder if i can buy the one that's made already? as shown above...I just couldnt have time to assemble one...i've started making my n=own kanife already, and i have a 1 x 30 " belt sander.


Cheers,
Mario Tin-ga

0
IJustLikeMakingThings
IJustLikeMakingThings

Answer 9 months ago

I'm sorry, my grinder is not for sale. But if you search 2 x 72 belt grinder there are lots of different fully assembled versions for sale.

1
SamBone29
SamBone29

10 months ago

Does anyone know how much it costs in total to build not including the motor?

0
infoseanalequin
infoseanalequin

Reply 10 months ago

i have the same question

0
LloydR13
LloydR13

11 months ago

Love your work and will give it a go. By the way this guy " jamespagan" has stolen your post calling it his own!

0
IJustLikeMakingThings
IJustLikeMakingThings

Reply 11 months ago

I'm glad you like it and good luck. After 2 years it's still going great. And thanks for letting me know about the stolen post. It's looks like it's stolen from both mine and the first one I reference. I'll let instructables know about it.

1
makingboat
makingboat

2 years ago on Step 11

Nice, I use a 12 inch disc sander for grinding knives. If you disconnect the start caps on the old Deltas they will start by hand either direction. This makes grinding both sides of the knife blank easy. But, I too have always wanted one of these.....It is now on my list

0
IJustLikeMakingThings
IJustLikeMakingThings

Reply 2 years ago

Interesting, I don't know if I've ever heard of anyone using a disk sander to make knives. That's great that you make it work. Do you use a jig for grinding or free hand it?

0
makingboat
makingboat

Reply 2 years ago

free hand mostly, it is very controllable...the only time I used a jig was grinding a dagger. (14 inch double edged blade) for a friend who does medieval reenacting.I think the disks are not used more often because they are normally unidirectional.... Mine is broken, this makes it better.