Well I stopped by Modern Tools and went through some junk and happened to find a boring bar but not the right size. In metric but one was just .010 over but I’m going to take apron off and see if it fits. Was hoping to use home made one cause I can broach the hole higher and use what I have left as a guid. Or I mount it and use the 3/4” to line up and then clamp it to the angle block then just the boring bar I found? Anyways I’ll take picture I think I’m going to make one and a round HHS sounds good didn’t think of that? Didn’t think they made round. Also picked up DRO Mount and Used Clamping Kit 5/8 I only needed a T-Nut but why not have extra clamping around my other ones are 1/2” so need the 5/8 anyways. Here’s a pic of what I found for down the road when I’m in trouble again. I’m gonna look on EBay for Broach like over $200 what I found local.There is 1\4 inch round high speed steel. That is what some of my boring bars are. The round hole can be filed square. The other option is there are bushing that are square on the inside and round on the out side that can be silver soldered in place. Good luck on the bar. Take a picture when you finish
I know that Chris Ramsay (ClickSpring) uses a little Sherline lathe, and generally makes smaller stuff in brass, but the principles are clear, and will work for 1/4 inch square. You might use a carbide tool to turn a taper onto a piece of 1/4 tool steel blank, or start from something harden-able, then heat, quench, and temper.Looking for 1/4” square broach to go through 3/4” round bar so probably long broach for cutting clearance. Need to make line boring tool with 1/4” high speed square tool.
Ya was checking that out. Seen some guys use a grinding stone. Grind diameter then a taper and the notches up to a square. Heading back to work so going to check around see what I can find or build or end up just buying broach. I’ll probably check out the round HSS should work fine also for the one time use.I know that Chris Ramsay (ClickSpring) uses a little Sherline lathe, and generally makes smaller stuff in brass, but the principles are clear, and will work for 1/4 inch square. You might use a carbide tool to turn a taper onto a piece of 1/4 tool steel blank, or start from something harden-able, then heat, quench, and temper.
Spare Parts #13 - Making A Square Broach
I have not yet had the experience of trying this myself, but he seems to know how. It seems very little of it is critical. You turn the taper onto the square, then divide it up in parting tool style. As you push or hammer it through a round hole, it progressively makes it square.