Slitting Arbor

Making a slitting saw arbor has been on my list for a while now and was finally inspired by a recent steam engine video by the Fabulous and Venerable Mr. Pete on his channel. He used one on his lathe to cut the connecting rod slot in the piston for it. It brought back the memories of the Green Machine fix where I used my Dremel Holder to cut the notch in the new head I made for it.

I had picked up 3 of these 100 tooth 2" blades a while back from HFT for another purpose all together but only used one of them. I also had one of their arbors for it but it was lets just say "Not Good" and had intended to make one, one of these days. I use some of their cut off wheels once in a while because a 6 pack is only a couple of bucks and they have thin ones like this 3/64" one.

I had a piece of 1" 12L14 (probably not the best choice but it works) so I cut off a piece and chucked it up in the lathe. Basically I took just enough off to clean it up and run true. Then drilled a #3 tap drill about .800 deep for the 1/4-28 SHCS I was going to use. Then I counter bored the end 7/16 x .250 deep for the 1/4-28 socket head.

Next I parted off the front section from it (~.750) and faced off the remaining piece. Next I used a 23/64 bit and drilled in about .50 to give a little drill angle at the bottom prior to the threads. Deciding it was probably better to counter bore before I tapped, I chucked up a 3/8" end mill in the tail stock and took it in about 7/16". After that I tapped the 1/4-28 hole to the bottom.

I figured I should be able to use this on other tools and decided to turn the other end down to 1/2" so it would still fit in the drill press or a drill motor. So I flipped it around and took it down to 1/2" and created the taper to the head at about a 45º, leaving lots of beef to secure the blades.

Next I chucked up the front piece and bored it for a clearance 1/4-28 and proceeded to turn down the collar to 3/8" and made sure I had a nice fit for the blade and cut off wheels. If I remember correctly the insertion depth of the collar is about 3/8". The trickier part was the return facing where it contacts the blade/wheel should have a bit of a cup to it so it will suck down on the blade. I set the compound at about 1.5º and went in to create the cup but got a lot of chatter no matter what I did, so I didn't do much, figuring it would just have to do.

This is what I came out with.

Once I tried the blade and cut off wheels in it I needed to trim the screw a bit because the 100 tooth blade is so thin, and just a bit of polishing to get the fits I wanted.

Over all it holds the blades tight and can be used on the Mini. The trick that Mr. Pete did was to mount his stock in a large tool holder. I can't do that on the Mini because it's limited to about 3/8OD or up to 1/2" rectangular or square stock to actually have any holding power in the A2Z tool post holders. I believe I can make a holder that will either fit in the current holders or use the old 4 way. The problem of how big the part is still lies on getting the part on center line.

You can see in the top picture and the ones below that I was able to cut a notch into a piece of .188 AL. Worked fine and need to take your time with this blade but it works on AL. I'll need to try it on other materials like brass and mild steel to see how effective it is over all.

Epilogue

I was real happy to be able to make this for myself on the Mini and it should be useful for some of the things I do. The cool thing is it didn't take very long to make ~1 hour and can always make another for some other style blades pretty quickly. Like most of the things I do like this, I did it on the fly, by whittling it with the help of the wonderful Mini and from the idea in my head!