Boring Bar Help
- Thread starter darvent
- Start date
Welcome to GJ!
In principle, it appears the cutting tool acts as an adjustable reamer. As such, it is the bottom of the tool, touching the table, that must be ground to sharpen it. I would hazard a guess, based on the design, that they individual blades could be removed and sharpened on a surface grinder in a fixture and then re-installed.
In principle, it appears the cutting tool acts as an adjustable reamer. As such, it is the bottom of the tool, touching the table, that must be ground to sharpen it. I would hazard a guess, based on the design, that they individual blades could be removed and sharpened on a surface grinder in a fixture and then re-installed.
Thanks for answers, my concern sharpening off the unit ,wnen replaced back on ,are all the cutters going to touch cylinder at same time ? . because now when measuring distance between two opposite cutters i get between .005 to .010 thou. difference compared to other pairs. So i wonder , if this unit is to be bolted solid to cylinder block only the outermost cutter will be doing all the cutting , don't seem logical . unless the unit is designed to be slightly bolted loose so machine can "self center" ,then 3 or 4 cutters could touch cylinder wall ? maybe I should post in antique column as it is very old , no one I have ever talked to knows anything about this unit
gdocktor3
Well-known member
I thought you were looking for some activities to do at your local watering hole... Karaoke, board games, darts, pool, ahhh nevermind...
To improve cylindricity, one would have to ensure all backlash was taken up in the mechanism. It would then be OD ground on a cylindrical grinding machine. Finally, relief could be added to the back side of the blades individually at the same time as the bottoms are sharpened on a surface grinder.
Re-assembling each blade in the correct location would be vitally important.
Re-assembling each blade in the correct location would be vitally important.
Packard V8
Well-known member
Thought I was familiar with most boring bars, but that's both old and odd. Can you confirm the manufacturers name?
jack vines
jack vines
Thanks for information, yes it is very old but in good working condition yet. it is "Canadian St Louis Mo. USA. tool and Mfg. Co. Ltd." Model C256. . regarding removal of cutters I did notice all cutters are etched with a number, as well as corresponding slots for reasembly. Do you think it would be advisable to leave the unit slightly loose on top of block so the cutting head can self center when in use , with 8 cutters it would almost have to bore straight ?
rsanter
Well-known member
Have you tried using it?
Does it really need sharpened?
Bob
Does it really need sharpened?
Bob
hi bob . Haven't tried it yet, was concerned when checked with a micrometer cutters are not all evenly expanded outward. about a variance of .012 between them. . they have no way to self adjust as they are expanded by a solid taper cone . there is no debris anywhere on cone ect. Maybe that .012 thou. discrepancy don't matter , got no instructions on this one. hoping someone has a manual too.
Shadowdog500
Well-known member
Try here. http://www.vintagemachinery.org/
People can upload and download old manuals for old machinery on that site. Perhaps you will get lucky.
Ive never seen a boring bar that wasn't single point.
Chris
That looks like an inserted blade reamer. The photos are from a 1950s Pratt & Whitney cutting tool catalog. Note that the second picture shows the parts breakdown and says the blades are furnished unground on the OD and are to be ground by the user after installation in the body.
Attachments
rsanter
Well-known member
I have to question if this is even a boring bar. With the reaming heat it seems like it is a portable reaming machine. I could see how this would be used with a large weldamant assembly where they have a large assemble welded up of many pieces then due to potential welding warpage they will want to final size ream holes before bushings go in.
I have a boring bar for engines and it is a single point unit. Every one I have ever seen was single point. Then you hone to final size and to establish the cross hatch
Bob
I have a boring bar for engines and it is a single point unit. Every one I have ever seen was single point. Then you hone to final size and to establish the cross hatch
Bob
OccupantRJ
Well-known member
Whatever it is for, the best way to keep it accurate is to reduce the diameter by adjustment, then adjust back out slightly to get the backlash out. The next step would be to regrind all cutting edges on a machine like a K.O. Lee tool and cutter grinder. That would insure that all blades are equal radius from the centerline of the tool. Even when grinding standard milling cutters, the starting point of each rotation of grinding has to be started in a different location than the last grind, to reduce loping that will occurr when the cutter is used.