$#!&%# Boring Issues!

[ronzo]

Hmmm, guess I better turn in my card because I always finish a bore by taking several spring cuts in both directions. It takes the spring out of the bar resulting in a precise bore and produces a nice finish. The only caveat is that the bar can sometimes chatter on the way out due to the extra cutting edge in contact with the work, but that can normally be remedied by shifting the rpm a bit. I'm curious as to why are you so vehemently against the technique.

Tom

I agree 100%. If you get the desired results do it. I do it all the time and have been for the last 65years.


Ron

 

[Richard King]

Hmmm, guess I better turn in my card because I always finish a bore by taking several spring cuts in both directions. It takes the spring out of the bar resulting in a precise bore and produces a nice finish. The only caveat is that the bar can sometimes chatter on the way out due to the extra cutting edge in contact with the work, but that can normally be remedied by shifting the rpm a bit. I'm curious as to why are you so vehemently against the technique.

Tom

The cutter he has pictured looks like it could be dragging and the chips coming off it don't look like they are being cut smoothly or with small curls or even a sting. I just zoomed in on the pictures the way Tommy Brooks showed me, (hit ctrl and the + ) and the tip looks chipped a little or off color) The experienced machinists here all know about push away and vibration To me the less push away or spring of a tool the less work and no guessing on the size when it finally straightens out, right? We all like to take a finish pass or two measuring as we go. This has been a learning experience for many of the readers interested in boring.
We have to bend a little (pun intended) on our advise I think.

A wise man on here told me recently it is difficult to type what your trying to explain and reading what is trying to be explained can be taken wrong. Sometimes and we have to give the benefit of the doubt when we are both trying to help someone on here. No need to confront each other if our opinions or ideas don't exactly agree. Tom that is why your movies are so good. Take out the conclusions or guessing at what we are typing. Thanks for your contribution to our industry.

I discovered many years ago when I was talking to a Journeyman Machine Tool Rebuilder who worked at Garrett in Phoenix where our company was sub contracting a rebuilding job on a Gleason Curvic Couping Grinder. He had got his Journeyman card at Pratt & Whitney and he hand-scraped with a hook motion taught by Moore and on the East Coast and I used the German or Swiss Method, you push and lift. He respected my technique and I respected his as we both were able to accomplish the job in the same amount of time.
Thanks everyone for your idea's and help. Rich

 

[clevinski]

The cutter he has pictured looks like it could be dragging and the chips coming off it don't look like they are being cut smoothly or with small curls or even a sting. I just zoomed in on the pictures the way Tommy Brooks showed me, (hit ctrl and the + ) and the tip looks chipped a little or off color) The experienced machinists here all know about push away and vibration. Thanks everyone for your idea's and help. Rich

Hi, Rich,

FYI, the tip was not chipped, but I understand why you thought so. I kept checking it myself for exactly that because it does LOOK chipped. It is some type of discoloration.

What I learned in getting this done is a LOT about push-away, carbide and boring cutter geometry. Thanks to all for the education!

 

[benmychree]

What prompted my comment about not boring on the way back out of a hole, is that in all my contact with long time journeymen during seven year work in the shop that I served my formal apprenticeship in, which was a sizeable busy place with lots of men working, this was never done; if you took a spring cut, you returned to start of the cut and ran it back in. One factor that may have effected it is that most of the machinery was pretty well worn and misaligned and just plain sloppy; feeding back out may have caused the cut to deepen due to the carriageracking on the ways, this is especially a problem on flat way machines as opposed to vee ways. Although they are not seen in industry, this particularly applies to the Atlas lathes, especially with wear and tear. In the shop above mentioned, we did not have any flat way machines, but all of them but two newer American Pacemakers were quite worn out, the wear down on the ways and carriages required approximatly 1/8" of shims to bring some of the tooling on center, and the tailstocks had about 1/16" of shims between the base and main casting. When feeding close to the chucks, the tools would dive in and cut significantly undersize, and it was a challeng to do acceptable work, which was possible, but at a cost of extra time to compensate for the inacuracies. On these lathes it would have not been possible to feed / bore on the way out.
A little controversy can be good for a forum such as this as long as it does not result in the personal attacks that plague the other sites that we have all visited and have been repelled by, and it was not my intent to attack others, but to state my opinion as to what I have experienced and have been taught along the way by competent professionals in my trade, which I have followed for 49 years and counting.

 

[Tom Griffin]

Thanks for the clarification. :thumbsup:

As Ronzo pointed out, "If you get the desired results, do it" and I heartily agree. You should never be afraid to try something new in machining. Whether it works out or not, you will always learn from the experience.

Tom