HSS or Carbide inserts fot lathe turning????

Coincidentally ive just noticed a user hear (tomG)has posted a new video on youtube about grinding cutters, looks good and he explains the angles with large sized models, very sensible)

you can find a thread he has a link to his utube vids by searching for "Using a Corner Rounding End Mill on the Lathe"

apologies i noticed it in my google+ feed on the tablet and have no idea how to get a direct link to the youtube vid from their :-0

Stuart
 
stupoty said:
Coincidentally ive just noticed a user hear (tomG)has posted a new video on youtube about grinding cutters, looks good and he explains the angles with large sized models, very sensible)

you can find a thread he has a link to his utube vids by searching for "Using a Corner Rounding End Mill on the Lathe"

apologies i noticed it in my google+ feed on the tablet and have no idea how to get a direct link to the youtube vid from their :-0

Stuart
Click to expand...

Hey Stuart- good catch!

I forgot Tom posted that! I believe this is a direct link:

http://youtu.be/0MAeOnobFIs


Bernie
 
I actually watched Toms video on tool bit grinding while I was at the docs office yesterday. (free WiFi). I still thought it was going to be a simple job. I just have to be patient.
 
You may have a catch 22 goin' on. If the material you're cutting is too hard, you'll need carbide to cut it. With a 6 inch lathe, (not familiar with that model) you may not have the rigidity required for carbide. Recently I tried to turn a torch cut piece of plate while making a collet drawbar. The HSS bits just would not cut it for more than a few seconds before dulling up and squealing. After three sharpenings in fifteen minutes the message even got thru my thick skull. Carbide blew right thru it. You can make your machine a lot more rigid by rigging up a way to attach the tool holder directly to the x-slide eliminating the compound. I did that on my old worn out Logan and it made a world of difference. Another thing that breaks carbide is touching the tip to the work to zero your dials before starting the cut. This often chips the very point of the insert and can be overlooked if you're not paying attention. Carbide needs to be pushed kinda hard for good cuts and doesn't like to be babyed with shallow DOC's and slow feeds. Good luck.
 
Have used those LMS carbide inserts. Have chipped them. Also have
chipped brazed carbide.

Taken .060 cuts, on soft steel, 1020. This is with brazed carbide.

I seem not to chip as much running carbide, 720 rpm and higher. Chip more
570 rpm.

This is with 9x20 and G0602 lathes. Use HSS for threading.

Would recommend Tom's advice for beginners, use HSS. Use carbide for stellite shut off
valves for oil rigs, and others, like machinists use at the Borg and Wagner Corporation.

My 2 cents.... Charl
 
Here is a Stellite cutter. Ground this and was hard on my grinding wheels, several years
back. I think originally its an insert or something, as it came in a bag of used cutters.

Have not found any metal it can't cut.

Charl

back.JPG front.JPG
 
Sounds like your main problem is that the pin is too hard. If I was designing an escalator, I'd use hardened pins. Best to keep to softer material until you have more experience with your lathe.

I've taken to keeping a small triangular file handy when I'm looking for stock (read in scrap). If the edge of the file easily cuts into the metal, it is soft enough to machine. If the file, which is very hard, won't cut into the piece, neither will HSS cutters. Carbide might, but then you need the rigidity mentioned above.

Charl is the first one I've noticed mentioning cutting speed. In the past, I've murdered a lot of cutters, both HSS and carbide, by not understanding about proper cutting speeds and feed rates, based on the material being cut.
 
Funny you mentioned that. I tried to run a file over some HSS cutters that I picked up at an estate sale. None of my files would even scratch the surface. I thought I'd be able to dress then up a bit........ NO DICE! I'll get some pictures up in a little while. My battery is charging.
 
To touch up the cutters you will need an abrasive stone. Either a fine diamond hand lap, or a fine india stone work great. Both are available for around $10.
 
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