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Poor Boy Split Nuts

General:

The screws and nuts that hold a saw handle onto its blade are getting to be either hard to find, or are exceedingly expensive.  The standard issue nuts from the hardware store are simple plated steel, and are not consistent in length in my experience.  The brass split nuts are available, but are limited in supply and quite expensive at about $5 each plus shipping at the time of this writing.  I  thought to myself that I could make them almost as well using a few simple tools found in most woodworking shops - and then I would be able to claim that the saws I make are made entirely by myself, something I thought would be kind of cool to be able to do.

Materials and Tools required

The split nuts themselves will be manufacture from 10-24 (or 10-32) threaded brass rod (1" long, from McMaster Carr) and plain 9/16" brass rod (9/16" is a common size on most saws with split nuts, but I've also seen 1/2" used), both available from good metal suppliers online (such as McMaster Carr or MSC Direct).  Tools needed are a hacksaw, a drill press, a 10-24 (or 10-32) TPI tap,  a disk or belt sander, and finally a grinder outfitted with a de-burring and buffing wheel.  A jig for making the nuts will be crafted out of some 8/4 ash, some 1/8" plate steel, and a threaded insert.

To make the bolts, a torch (along with all the necessary accoutrements)  is necessary for silver-soldering the nut to the threaded brass.  An oxy-acetylene torch is the best tool for this job - however, here I am use one of those $50 welding kits that use a small bottle each of MAPP and oxygen gas.  These small kits supply plenty of heat for the job, and are much less expensive than buying a full oxy-acetylene rig. If you do a lot of soldering, this is not very cost efficient method - but for occasional use, they works fine.

You will also need some silver solder and flux - I use a brand called "Stay-Silv 45" for the best results.  This should be available at most good welding supply stores.

A Simple Jig, and Making the "Tube"

What's needed first is a way to drill a  hole through the center of the brass rod in order to thread the nut.  The hole must be sized for the size thread you want to tap, and centered in the rod to be proper.  The only way to do this is to build a simple jig to hold the brass rod upright so the hole can be drilled into it's center.  You will see the jig in many of the following pictures here, and I won't go into too much detail on it because of it's simplicity.   

Using a forstner bit that's the size rod you are using, I drill a vertical hole into some 8/4 ash, not all the way through, leaving about 1/2" of wood at the bottom so the rod won't fall through.  I then pick a spot on it's side near the top and drill an additional 3/8" hole from the side, centered on the previous hole.  Into this hole I insert a threaded insert - this will allow me to use a small bolt to "lock" the brass rod in place, so it doesn't turn in the hole while drilling it.  

A small piece of steel mounted on the side of the ash was added when the threaded insert I used started wanting to strip out of the wood - the steel is there simply to hold the threaded insert in place in its hole.

Once the jig is complete, I take a 7" or 8" section of brass rod, and insert it into the jig.  Using a center finder, I locate the center of the rod and use a center punch on it to locate it for the drill bit.  I place the entire assembly on the drill press, and drill a 13/64" hole in the center of the brass rod to the drill bits full depth:

Drilling it to the full depth of the drill bit is necessary for the next step, which is tapping the hole for 10-24 thread.

Making the Nut

The next step is to tap the brass rod using a 10-24 tpi tap:

Tap to the full depth of the tap - on subsequent nuts, it's occasionally  necessary to drill the center hole a little deeper to accommodate the tap.

Now its time to add the slot for the nut - you can skip this step if the nut is to be used for the bolts.  I use a hack saw to make the slot:


Cut to a depth of about 1/8" to 3/16" or so, making sure the cut is level across the nut - then cut the nut off, making sure you make the cut as straight as possible and about 3/16" further down the nut than the slot is deep:

Set the new nut aside and start the process over, making another then another until you have as many nuts as you need.

Thicknessing and Polishing the Nut

You now have a rough nut that is much too thick for use in a saw, and probably not cut quite as square as it should be.  To reduce the thickness and level off the nut, cut the thread off of an 1-1/2" long bolt with the same threads, place 2 nuts ( locked together) near the end (with about 1/8" or so of thread sticking out of the outermost nut) and chuck the affair into a hand drill.  Thread one of your newly made brass nuts onto the end of the whole affair and bring it over to the disk sander.  Use the drill to spin the nut, and sand it to thickness:

You have to ever so slightly cant the assembly to the left to keep the brass nut threaded onto its holder - otherwise the spin of the disk sander will unthread it, sending it flying under the nearest bench and into the most inaccessible spot it can find.  When that side is done, unthread the nut, flip it over, and do the other side in a similar manner.  Keep a pale of water handy to cool the nut so you can grab it, because the brass gets hot! 

Watch the depth of the slot cut into the nut and use it as a guide - you want the slot to be about 1/2 the thickness of the finished nut, which should be about 1/8" to 3/16" thick - I  shoot for exactly 5/32" thick.  You can put a slight chamfer on the back of the nut, both for looks and so it seats itself flatter in the wood when used in case there is sawdust in the way.

Once the nut is to the correct thickness, a trip to the grinder where you have a deburring anmd polishing wheel installed will give the nut a finished polish:

From here, its on to make the corresponding bolt.  I used the same slotted nuts for the bolt - you may wish to use an un-slotted nut and make a shoulder for your bolt.  If that is the case, you can make those by using the same process above only eliminating the slotting step above.  

The next page will continue with making the corresponding bolt...

Comments

Comment: 

That is awesome. I found an old split-nut yesterday and spent an hour trying to figure out in my head how to make my own - and you've already got it down to a science. Luckily I've got a great mill/drill and a sander so this should be a fun little project once I get some brass rod.