MLA-23 QCTP Boring Bar Tool Holder
I wanted to share a project I’ve been working on the last couple of nights. I’m preparing to machine a faceplate and thought it would be a good excuse to make a boring bar holder for my quick change tool post. The plans included with the QCTP drawings called for brass-tipped set screws for the holders, but I’ve been wanting to try some cotter clamps ever since reading about them in Lautard’s First Machinist’s Bedside Reader. I’m very happy with how it turned out so far, and I’m excited to use it soon on my next project. I ran out of space for the height adjustment screw, which normally get put right in the middle of the holder close to the dovetail. Since I wanted to keep the bar as close as possible to the post, I opted to move the screw to the front of the holder. It makes full contact with the base plate and I do r expect I’ll have any issues with it there. Next up is drilling the bar for the cutter and clamp.
Nice.
John
Sent: February-19-22 4:11 PM
To: SouthBendLathe@groups.io
Subject: [SouthBendLathe] MLA-23 QCTP Boring Bar Tool Holder
I wanted to share a project I’ve been working on the last couple of nights. I’m preparing to machine a faceplate and thought it would be a good excuse to make a boring bar holder for my quick change tool post. The plans included with the QCTP drawings called for brass-tipped set screws for the holders, but I’ve been wanting to try some cotter clamps ever since reading about them in Lautard’s First Machinist’s Bedside Reader. I’m very happy with how it turned out so far, and I’m excited to use it soon on my next project. I ran out of space for the height adjustment screw, which normally get put right in the middle of the holder close to the dovetail. Since I wanted to keep the bar as close as possible to the post, I opted to move the screw to the front of the holder. It makes full contact with the base plate and I do r expect I’ll have any issues with it there. Next up is drilling the bar for the cutter and clamp.
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
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efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)
I wanted to share a project I’ve been working on the last couple of nights. I’m preparing to machine a faceplate and thought it would be a good excuse to make a boring bar holder for my quick change tool post. The plans included with the QCTP drawings called for brass-tipped set screws for the holders, but I’ve been wanting to try some cotter clamps ever since reading about them in Lautard’s First Machinist’s Bedside Reader. I’m very happy with how it turned out so far, and I’m excited to use it soon on my next project. I ran out of space for the height adjustment screw, which normally get put right in the middle of the holder close to the dovetail. Since I wanted to keep the bar as close as possible to the post, I opted to move the screw to the front of the holder. It makes full contact with the base plate and I do r expect I’ll have any issues with it there. Next up is drilling the bar for the cutter and clamp.
Thanks all!
I finished up the boring bar this morning. It’s a piece of 7/16” 4140 that I was going to use to remake the cross slide screw for an 11” Logan that I sold before I got around to it. I was thinking originally that I would make a more complicated threaded cap that would lock the cutter in place like I have one of the bars that goes with my Armstrong No 8 holder, but then came to my senses and just put a 1/4-28 set screw in the end. The square hole was filed by hand after cross drilling 3/16”. Now I just have to grind a couple of cutters, including one for the 60 internal threads I started this project for.
