Comm lathe questions

firebirdude · 04-10-2008, 07:24 AM

What makes one comm lathe worth $175 and one worth $35? I see lathes going for under 50 bucks with diamond tips all the time.

joe of loath · 04-10-2008, 08:05 AM

Quote:

Originally Posted by firebirdude

What makes one comm lathe worth $175 and one worth $35? I see lathes going for under 50 bucks with diamond tips all the time.

depends on the age, condition etc. new ones are easily £100+, while second hand ones can be found all over as people switch to BL for less than £50.

OTE_TheMissile · 04-10-2008, 08:13 AM

DO NOT BUY A DIAMOND TIP! Just because it's diamond doesn't mean it's better, I've heard more than my fair share of horror stories from guys who've accidentally cracked or chipped diamond tools, and then they're junk, and it's not very hard to do. The thing is, where a carbide tool will produce a poorer and poorer surface finish as it wears out, diamond tools leave a clean finish even when they're bad, so while it might make a comm look pretty, that's no guarantee the cut was true, concentric, or consistent.

Comm cutting masters might feel safe dropping $80 on a diamond tool, for the rest of the planet, using a $4-6 carbide tool, getting it resharpened a few times at a local machine shop, and tossing it when there's nothing left is the way to go. I bought 4 replacement carbide tools from McMaster-Carr some 4 years ago, and as of today I've only worn out one or two. I can still take them both in to be sharpened.

mr. losi · 04-10-2008, 12:22 PM

hold the phone....i have never gotten a carbide tip to cut right.....conversely i have had a diamond bit on my trinity lathe for over 10 years, never had a problem........

so i disagree, diamond is the way to go.......

LOSI BOY-MF2 · 04-10-2008, 01:59 PM

Quote:

Originally Posted by mr. losi

hold the phone....i have never gotten a carbide tip to cut right.....conversely i have had a diamond bit on my trinity lathe for over 10 years, never had a problem........

so i disagree, diamond is the way to go.......

I would have to agree, I've had some problems with a carbide bit and never had an issue with a diamond bit.
If your still turning comms the diamond bit is the way to go.
As far as the original question. some lathes are just built better they have some that are atomatic and some are manual some have V blocks while others have bearing, and some have better motors. In the end you will get what you pay for.