My lathe came with a brazed carbide boring bar set, which I have used in a grooved quick change holder. I also have a larger index-able carbide boring bar with quick change holder. My current turning project is in acrylic, not steel or aluminum, so I think I will need to use HSS bits to get the rake and trail that I need. I am looking at the older style boring bars and wondering if the need the square clamping block or can I just use the quick change holder that has an alignment groove opposite to the screws.https://www.busybeetools.com/products/boring-bar-set-4pc-1-4in-5-16in-3-8in-1-2in?_pos=9&_sid=f9f301c14&_ss=r&_fid=44a32c44e
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Tool boring bars for HSS bits
- Thread starter ColinB
- Start date
Tool
ChazzC
Ultra Member
I have not had good success boring plastics with carbide insert tools. But I confess I have not tried inserts for Aluminium which are much sharper. They might work but I don't know that.
With what I do know, I would use old style boring bars that typically take 1/4" square bar HSS Blanks like the ones you linked.
Thanks. That's what I found on
How to Machine Acrylic: Get it Right the First Time! | Make it From Metal
Ok, so a slight deviation on the typical theme for a site called "make it from metal", but it's close enough, right? It seems like…
makeitfrommetal.com
I feel like I would get more bang for my buck, buying old school HSS bits. There's a lot more HSS to work with.
I'm thinking about using Aluminum inserts, but will probably order a traditional boring bar set. It seems like they will be more versatile, cheaper and suitable for the slower turning speeds that my lathe is capable of.
Aluminum inserts works beautifully in most plastics. When you speak of costs you value your time?
What lathe do you have ? I ran insert tooling in my southbend 9, it was worlds better than any hss I ever ground/bought
I've had good luck turning plastics with sharp uncoated carbides intended for aluminum" - Nylons, UHMW, Teflon (I think acrylic but its been a while). Some plastics just have their own characteristics so you may have to experiment with speed & feeds. Heat usually spells trouble so monitor that. Some people use a spritzer of water based coolant. I've even heard of methanol but haven't tried myself. You have to be careful with cutting tools big contact areas like large diameter drills or round-over tools because some plastics can get grabby especially with localized heat near the edge. Be careful with swarf too, they can turn into strings & then balls of strings
I usually turn acrylic using HSS cutter. I have good results if I grind a good radius (1/16") round nose on the end. The radius help reduce stress point on your parts. But if you anneal the acrylic after machining it won't mind sharp corners.
I sometimes need coolant, I then , mix some water and dish soap.
I sometimes need coolant, I then , mix some water and dish soap.
ChazzC
Ultra Member
ChemE Department Toolmaker always used water & liquid hand soap when machining Acrylic.