Homade Boring Bar

[Nebraska Kirk]

When rebuilding an antique tractor last year, I ran into an issue with the front axle pivot mount. The pivot pin is supposed to remain stationary in the mount, but over the years and who knows how many thousands of hours of field use, the pin had evidently gotten loose and wore the holes egg-shaped. I made this boring bar to use in my lathe to bore the worn holes round again. Building this tool required making a tool to use in making the tool to bore the worn hole! I needed to broach a square hole in the bar to hold the tool bit, so I made a square broach out of a 1/4" HSS tool blank, I ground it tapered on all 4 sides and then, using a Dremel with a cut-off wheel and an assortment of grindstones, I cut the teeth and ground the clearance for them. That was a tedious job! I did drill the hole a little over 1/4", 9/32" I think. When I pressed the homemade broach through the hole, it worked pretty good and cut a nice square hole, I did have to file it some until the 1/4" cutter would slide through easily.

Here is a video and pictures of the boring bar in use.

 

[JimDawson]

I like it!

 

[Bob Korves]

Great job of being resourceful on building the line boring bar! Machinist makes the tools that build the tools that repair the unavailable parts to get the irreplaceable tractor back in action...

 

[kd4gij]

Nice job on the line bore.

 

[Bob Korves]

These:
http://www.sdp-si.com/web/html/newprdrsleeves1.htm
are the easier way to fit a square tool into a line boring bar. Kirk gets extra points for making the broach and getting by with what he had on hand!

 

[Nebraska Kirk]

Thanks, Bob! I did not know about those sleeves when I made the bar. This 12x36 Atlas lathe was my very first metal-working machine, I have had it 5-6 years now and while it is pretty light duty and not the most accurate, I have used it for a LOT of different things. Now I have a Bridgeport vertical mill too and it is the cat's meow!!

 

[Bob Korves]

Thanks, Bob! I did not know about those sleeves when I made the bar. This 12x36 Atlas lathe was my very first metal-working machine, I have had it 5-6 years now and while it is pretty light duty and not the most accurate, I have used it for a LOT of different things. Now I have a Bridgeport vertical mill too and it is the cat's meow!!

Pretty gutsy. I would probably have just drilled a round hole in the boring bar and made a tool bit out of the shank of a broken end mill.