Lathe Boring Bars

[Phil3]

Paddy,

Wow, I very much appreciate your time and effort to provide such helpful information. The Front Page sentence that reads, "If you are tired of the drama, nastiness and elitism on other machinist sites, you have reached the right place"! is really true.

You wrote that a boring bar is the preferred method for a straight, true hole. If the reamer follows a drilled hole that runs out, the reamer can't fix it. Where might a reamer be used or be superior to the boring bar? Small holes that a boring bar can not reach into?

You asked what tool post style & size does my machine have. I use the Phase II AXA size QCTP. The boring bar tool holder has a bore of .75" with a sleeve that can hold a .625" bar. This is it here. http://www.littlemachineshop.com/products/product_view.php?ProductID=2283&category=

You said the HSS bits are always made to be removed, resharpened and replaced. I think this is where I am way of base. Consider this image from Borite.

http://www.boritemanufacturing.com/hi-speed_tools

Those look to me like solid ONE piece bars. That is, once the cutting edge is worn down and resharpened enough, it is at the end of its useful life. I don't see anything that can removed, resharpened, and replaced. Maybe it is the image that fails to show me how this works.

What is the proper name of the boring bar with the removable bit and set screw?

It would appear that a boring bar with indexable HSS insert would work well for my machine. I am not sure that exists. That would be a tiny piece to hold and sharpen.

Thank you.

Phil

 

[Maglin]

I have the Shars SCLCR 3pc. set. I like it but even the smallest bar still requires a large starting hole. When in a pinch you can also make one out of an old broken end mill and your grinder. I recently had to bore a hole to a shoulder in some aluminum about 1" and was around .350". I had a 1/4" drill blank and made a boring bar out of it. I was very very surprised at how well it cut. I only gave it .008" of clearance since it was already a very small piece of HSS. The surface finish was as good as a reamer, but I did have to take light cuts so it took me a little while. I had to start with a drill 2 sizes down for that just in case.

I've been thinking about getting the Maritool solid carbide bars or a set of the Everade bars. I've head great things about both and both have their different uses.

 

[Tony Wells]

To be honest, I won't use HSS if I can do it with carbide. If it's a one-off, or large corner radius or something like that.....sure, but otherwise, carbide for me. Inserted. I hate grinding.