Square steel bar to round?

[airborne_r6]

I am making my own carbide turning tools. I am using a 1/2" square bar in 1018 steel. For the tang that inserts into the handle I would really like to find a way to make the square steel bar into a cylinder so I can just drill a hole and epoxy it into the handle.

Does anyone have an idea for a way to do this that will give me a consistent diameter on the tang and wont take forever to do each one?

I have a wood lathe, a couple grinders, files, hacksaws, etc. at my disposal.

I could just drill the hole and chisel it square to fit and I also have access to someone with a metal lathe who can do it for me. I will do one of those things if I can't figure this out.

Just completing the tool is not the point of my question. The point is I would like to see if I can figure out how to round the tang end myself.

 

[Leatherman1998]

You can soften the corners with a belt sander, grinder, or file (will take longer) and drill the hole in the handle a little larger. Thats just my $0.02

Levi Woodard
Woodardwoodworks.com

Sent from my Rooted Galaxy Player.

 

[PTsideshow]

Depending on how round you want it outside of using a metal lathe, cheapest, fastest and you can have the same dia the full length or tapered. Using an angle grinder to round the corners off would be easier with a fixture and 3 jaw chuck or collet holder so you can turn the square easy.
The lathe was invented to take the corners off. U should use it :biggrin:
:clown:

 

[skiprat]

Ok, I'll bite and ask the stupid question....:tongue:
If you are going to epoxy it in the handle, why do you need to make it round first?

I would drill a big enough hole and half fill it with epoxy then stick it in until set.
I'd also either cut grooves or drill some holes in the tang so that the epoxy gets a good grip. :biggrin:

 

[airborne_r6]

Ok, I'll bite and ask the stupid question....:tongue:
If you are going to epoxy it in the handle, why do you need to make it round first?

I would drill a big enough hole and half fill it with epoxy then stick it in until set.
I'd also either cut grooves or drill some holes in the tang so that the epoxy gets a good grip. :biggrin:

I don't need to at all, like I said before its not about finishing the tool, I just want to do it.

It really comes down to I finished shaping the tool Friday night but didn't get a chance to get wood for the handle Saturday and the stores with decent wood for handle blanks are closed today. So it left me time to think. This is what I started thinking about.

So far I have come up with attempting to mount it to the lathe and make a quick handle that will hold the carbide tools used on a metal lathe, but this is of very questionable safety and unlikely to yield a decent quality cut.

I have thought of holding it in the lathe and making a shelf to hold my 6" bench grinder against it but I think this will generate way to much heat and most likely shatter the grinding stone.

I have thought of using the grinder to get it close and then mounting it in the lathe and using a file to clean it up but this seems like it will take forever.

I have considered mounting a cross slide vise to my lathe and using the vise to hold a tool post and make it act like a metal lathe but I don't have either a cross slide vise or a tool post.

I am just curious if anyone has done it or thought of a way to do it other than what I have already thought of.

 

[Emery]

I made the handle for my square bar by drilling a hole in the handle with a diameter slightly smaller than the diagonal of the square bar. I then ground off the edges of he bar until it fit snug and epoxied it. I have had no issues.

 

[juteck]

I rounded mine with a belt sander. Close enough to round to fit in a drilled hole.

Or, make a laminated handle. Make the center strip using a wood with same thickness as square steel stock. Laminate two outer pieces to center core, leaving a gap in the center core to match your steel.

 

[longbeard]

Same as John here, i used a belt sander. Shouldnt take longer than about 10 or 15 mins. Have a bowl water to keep it cool as you go.

 

[Dale Parrott]

I didn't see this idea listed so forgive me if I missed it. Thinking outside the box here. How about making the handle out of 4 pieces of hardwood glued up leaving a square hole in the middle for your bar. You could glue a wooden plug in to close the end opposite the steel. I haven't tried this but maybe some one has and could let us know if it would work.
Dale

 

[robutacion]

Post #6 and #7 (laminated handle) are my suggestions in your case, if the handle has enough throat wood, a larger hole and epoxy is the quickest way, just make sure your shim the square(ish) bar, to keep it straight/centered while the epoxy sets, if the shims (wood/anything) are put half way down into the whole, the epoxy will run further down and fill the hole completely, and the shims will be fixed there, forever...!

Making a laminated handle to accommodate the steel bar size, is also a very easy thing to do, you can then turn the handle to shape and then epoxy the tool shaft into place, easy...!:wink::biggrin:

PS for this lamination option, make sure that the steel bar is inserted/glued with the cutting face, 90° from the wood glued flat surfaces, the forces exerted on the tool/shaft when used, will be a lot firmer if not the handle weaker point which is the flat surfaces of the lamination, where it could "peel" off or separate, otherwise...!

Cheers
George

 

[duncsuss]

My take on this: if you want to turn metal, buy a metal lathe.

You can get away with using a wood lathe and tools for soft metals like brass and copper, but for tool steel ...

I've put handles on several tools made from square steel bar. Knocking the corners off the square is easy using the grinder, getting it round-ish is far more tedious, and getting it round is ... well, I just didn't have the patience for it. :biggrin:

I've also put a handle on a (perfectly round) Doug Thompson detail gouge. Because the steel fit perfectly into the hole I drilled, it was harder to epoxy in place than the square tools.

Epoxy makes a good seal, and the air trapped behind the tool compresses as you push the piston into its cylinder ... then pushes the tool back out of the handle when you let go.

(The trick is to drill a tiny relief hole from the side of the handle into the bottom of the tool well. Any surplus epoxy is forced out of this hole.)

 

[Justturnin]

Also, maybe a bit dangerous but you can insert the square stock in your wood lathe, use a 60* center drill and put a 60* hole in it. Extend it out and bring your TS up to it w/ a 60* live. Get you a nice sharp file, and turn it at a slow speed and slowly file the corners off and get it round. Just be SUPER CAREFUL not to let the file touch the chuck.

 

[airborne_r6]

...I've also put a handle on a (perfectly round) Doug Thompson detail gouge. Because the steel fit perfectly into the hole I drilled, it was harder to epoxy in place than the square tools.

Epoxy makes a good seal, and the air trapped behind the tool compresses as you push the piston into its cylinder ... then pushes the tool back out of the handle when you let go...

I'm glad you mentioned this.

Here's what I ended up doing:
I am planning on using walnut to make the tool handle and I really didn't want to laminate it to make a convenient square hole; I also didn't want to chisel a hole square; I also didn't want to buy a drill bit big enough to fit the 1/2" square bar because I don't need it for anything else. I decided to use a combination of the grinder and lathe to reduce the diameter of the tang.

(Sorry about the orientation of some of the pictures, that's the way Photobucket has decided we need to see them.)

I ground the corners down until the distance across the new flats I had created was between 0.490-0.480". This created an octagon that measured 0.500" across two directions and slightly less across the other two directions. It was also 0.530" across the points of the octagon.


I then mounted the bar in my lathe and used a file to round off the corners until it measured 0.500" across the corners. I also used the corner of the file to cut some grooves to help the epoxy grip it. You can't really tell from the photo but I am standing to the side and am holding the file so that if it grabs it will not hit me and my left hand is only pushing down on it so it won't pull that hand into the spinning piece.


This created a tang with four slightly rounded sides which will fit snugly in a 1/2" hole and four flat sides that are slightly smaller which will provide space for glue.


When I first did it I ran into two problems. First, I tried free-handing the grinding and it didn't turn out very even, which isn't a big deal aesthetically because it will be hidden in the handle but it did create more filing. Second I tried to drill the hole in the end for my live center using the lathe but the lathe didn't hole the bar centered enough and so the hole was really off center. I ended up using a cup center to hold it while I filed it and then cut off the part in the cup center.

I made a second one and corrected those two things by making a v-cut jig to hold the bar so the grinding was even and I marked the center, hit it with a center punch and then used the drill press to drill the hole for the live center. Even doing that took two tries because my first center punched hole was just slightly off center and I didn't realize it until I had drill it with the center drill.


Comparison of the two finished tangs. The closer one is the second one and you can see there is less rounded area which meant considerably less filing.

 

[mikespenturningz]

What about mounting your new square shaft in your wood lathe so the end you want to round off is sticking out of the chuck. Then leave the lathe on a slow speed and use a file to work it down. I think it will work? You may want to work those corners down a bit first with the file then turn on the lathe and have at it.

 

[airborne_r6]

What about mounting your new square shaft in your wood lathe so the end you want to round off is sticking out of the chuck. Then leave the lathe on a slow speed and use a file to work it down. I think it will work? You may want to work those corners down a bit first with the file then turn on the lathe and have at it.

Two reasons, one I decided I didn't want it perfectly round and two my chuck doesn't hold it straight enough on its own. Without the tailstock support it would end up tapering the bar. I did chuck it up to see if I could do that before doing what I did.