Introduction: Metal Chop Saw From Grinder Made of Wood

Picture of Metal Chop Saw From Grinder Made of Wood

This is a homemade chop saw for small metal stock. I made this from wood and a cheap Harbor Freight 4 1/2 inch angle grinder with a cutting wheel.

Step 1: Gather Materials

For this project in used some scrap lumber, a 2 inch hinge, a pipe clamp, and the grinder.

The wood is 1/2 inch plywood for the fence and base and a 2x4 for the cutting table. The grinder cradle is also plywood.

The hinge and pipe clamp are standard issue. All grinders are different but on average a 4 or 5 inch pipe clamp should be enough.

The grinder is a 4.5 inch ultra steel brand which is availible from Harbor Freight. This is their cheapest grinder and often goes on sale or has coupons from their website. I got mine for less than $15.00. Many people bash harbor freight for being low quality but I have had decent luck especially for the excellent prices. This project can be done with any brand grinder.

Step 2: Grinder Cradle

Picture of Grinder Cradle

This step will differ based on the grinder. I cut a piece of plywood the width of the grinder. Next came two peices vertically to create a c shaped channel for the grinder to lay in. It is important for the power switch and all controls to be easy to access.

Step 3: Cutting Table and Arm

Picture of Cutting Table and Arm

To make the cutting table I started with a 2x4 and cut a deep groove through it for the blade of the grinder to fit into.

Next I attached that peice of 2x4 to a peice of plywood. I used a large rectangle of plywood to also attach the cutting arm and hinge onto. the plywood is bigger than the cutting area so it can be clamped to a workbench. I also drilled holes in it so it could be hung on the wall for storing.

The hinge attaches to the the piece of 2x4 that is perpendicular to the cutting table and then the grinder cradle. It is very important that the hinge and grinder is very square to the fence so tje cuts will be square.

To outline: this is a T shape made of 2x4 attached to plywood. on the short end of the T there is a hinge that swings a cradle holding a grinder.

Step 4: Fence

Picture of Fence

The final step was to add a cutting fence. The fence to make sure cuts are square and hold the workpiece steady.

Currently there is no clamp for the fence like on a big metal chop saw. I am holding the peice being cut much like a wood on a compound miter saw but I could use a clamp if needed.

The fence is made from the same plywood. It rises above the cutting table about a .75 inch. I cut a notch in the fence so that it would fit around the 2x4 that holds the cutting arm.

On the back of fence I used two screws to make a holder for the grinder arbor wrench that to make it handy for blade changes.

Step 5: Finished

Picture of Finished

This cutting jig works great for small stock. I haven't tried anything big but for me I usually only work with small stuff. I think with rotating or spinning the workpiece this could handle 1 INCH or maybe 1.5 inch angle iron.

Its not on for the picture but the safety guard does fit and is used for the tool.

This cost almost nothing to make and for what I do with metal working is great compared to the cost of a full-size chop saw this is a great alternative.

Comments

uncle frogy (author)2016-05-26

I will replace the cheap small hinge with a 4" door hinge mortised into the wood.

I might make some semi-circular cradles for my small L-grinder

I have been thinking about making one of these but mine tend to get overly complicated.

this will work and not take three days to build

uncle frogy

ernstp (author)2015-10-11

Very nice build. I found your project since I had almost the same idea. Nice someone else proofed it already.

I think replacing the hinge with bearings would make the saw more accurate. Ebay-china-quality would be good enough.

vincent7520 (author)2015-01-02

Nice… But how do keep the blade square to the guard ?… I feel some movement will appear after using it for a while.

tjdux (author)vincent75202015-01-02

I missed that you said guard. Are you asking about the blade saftey guard or the table fence? The blade guard actually attaches directly to the grinder. Otherwise the hose clamp holds everything tight and could be loosened and adjusted if it wears out of square. The hinge is currently the weakest part.

tjdux (author)vincent75202015-01-02

While building the jig I kept checking alignment with a square and adjusting before finalizing any of the wood joints. The grinder fits somewhat tight into its cradle and then the hose clamp is very tightly keeping it in place. Not tight enough to damage the plastic housing but there is no wiggle of the grinder itself. Very solid.

There is some play in the cheap hinge already. it's not perfect. When doing light duty metal working a tiny bit of slack can be made up for when welding.

For more preside work an extra 1/16th of an in can be added to the cut and then ground off or recut if needed.

Even high dollar pro chop saws can be a little inaccurate especially with small stock wiggling in the clamp. This is often worse when doing angled miter cuts.

Even with some play this is still easier, more accurate and faster than doing it 100% by hand.

makingbrad (author)2015-01-01

Really great project! Thanks!

rimar2000 (author)2015-01-01

This is a useful tool, thanks for sharing.

Phil B (author)2015-01-01

One of these I built with welded square tubing is linked on the right side of this page. How much cutting depth you have available depends a lot on how much of the cutting wheel has not yet worn away. I do find what I can cut has a broader range if I stop and rotate the piece a little, like a piece of pipe. I can use the existing cut to keep the cutting wheel aligned with the cut so the finished cut is smooth. I have also found the wheel stops cutting if the steel gets too hot. Although I do not fully understand that, I have learned to go slowly and let the steel cool, if necessary. I made mine with a fence I can move and clamp where I want it for more cutting options, like angle cuts or cutting wider materials. I hope you enjoy yours. I tweaked mine and made changes as new needs became evident.

BeachsideHank (author)2014-12-31

This is a nice build, I've been thinking of making one as a slider version for some decent crosscutting ability on flat stock. I agree with you on H.F. tools, I use them all the time in my shop: their NQA return policy and liberal warrenty is better than most in fact.

tjdux (author)BeachsideHank2014-12-31

1000% agree with the NO QUESTIONS ASKED return policy. Nobody else really does it that easy especially for power tools. And the lifetime warranty on the Pittsburgh hand tools. Never had to use it yet but its hard to beat when combined with the prices.

A sliding version of this would be great for cross cutting. Basically add some drawer slides to the cradle concept here and you would be close. Keeping everything square would be the toughest part. A small misalignment will be magnified the farther out the cut is extended. I would love to see how you make one.

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Bio: I grew up on a farm where we had to be very self sufficient and DIY. Hard work and making and fixing what we had ... More »
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