Checking for twist? and tool holders and inserts, Jet BD920W

C-Bag said:
Is there a reason you don’t just pull your tool post and set your level on the carriage while you run the carriage down the ways? That’s what I did.
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It sounds too simple. LOL. So, is what you’re saying to put my level on the compound up by the headstock, check it there, and then hand crank it down to the other end of the Ways where the tail stock is? If so that’s the easiest thing I’ve heard so far. I just didn’t think you could do that because it would throw the level all over the place. especially if I use the precision level that I should be getting shortly
 
I forget where I saw that, but to me it made real world sense. Now I’m not a machinist, I came from auto and engine machining. But the deck of the carriage of the 9x20 is a nice machined surface. The only thing that can change is the twist of the ways because the carriage is the same no matter where it is. It is too easy. And to over think is too alluring. if I was going to be doing work for NASA I’d not have a 9x20. Good work can be done on it but it is firmly in the hobby class. And to loose sight of that can make you crazy. Like the old adage says you can’t make a silk purse out of a sows ear but you can still make a pretty nice purse :)
 
I use the cross slide as a platform for the level and, at least in my experience, it is more accurate than using blocks on the ways. I can get my lathe leveled within a few tenths this way and I can get it the rest of the way, to zero, with a 2-collar test.

It works.
 
C-Bag said:
I forget where I saw that, but to me it made real world sense. Now I’m not a machinist, I came from auto and engine machining. But the deck of the carriage of the 9x20 is a nice machined surface. The only thing that can change is the twist of the ways because the carriage is the same no matter where it is. It is too easy. And to over think is too alluring. if I was going to be doing work for NASA I’d not have a 9x20. Good work can be done on it but it is firmly in the hobby class. And to loose sight of that can make you crazy. Like the old adage says you can’t make a silk purse out of a sows ear but you can still make a pretty nice purse :)
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I think because, as you say I’m overthinking this way too much and i’m trying for perfection on this hobby lathe And watching too much YouTube. The ways of the bed are machined very nicely and speaking with jet I know they’re hardened and ground. I’m just going to do my best throw some chips and see what happens thanks again for all the input
 
Larry$ said:
Please take my comments with a grain of salt, I'm no expert, just an opinionated old man.
Small lathes usually are not very powerful or ridged. Inserted carbide tooling generally runs best with enough force to overcome the eased edge that is there to limit chipping. There are inserts made with sharper edges specifically for overcoming shallow cuts on a small lathe, buy those. There are many advantages to HSS tooling. Easy to grind to any required shape, cuts freely requiring less power and less force. Cheap! You can also buy HSS inserts, not cheap. Given the cost to buy a box of 10 name brand inserts and their associated quality tool holders and all the different configurations you will need, you are talking a lot of $$$. Get an 8" bench grinder, G or H Norton wheels a star & a diamond (for shaping the wheel to other than flat) dressers.
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LOL Larry, I'm taking it with a grain of salt LOL. any advice to me at this point is good advice. thanks. I narrowed it down to putting these grizzly tool holders in the cemetery. I will be buying the A.R. Warner 3/8'' 3 tool kit#8 with HSS inserts. At least it is a starting point because I don't feel comfortable with the 1/2''x 1/2'' holders in an OXA post. I believe there is just too much overhang.

I have an 8'' bench grinder, an will look into G or H Norton wheel with a diamond dresser. someone else gave the advice to get HSS blanks and grind as neccessary which I thought was a great idea .
 
Cadillac said:
I have a jet 9x20 also and one way to check the ways is to use parrallels. They will fit on the ways and you can check twist. Another way would be just put the level on the carriage and move the carriage back and forth.
As for tool holders and qctp size I have axa qctp on my 9x20. For the most part I use 3/8 tools. I use carbide and hss tooling. If going carbide use ground inserts that are sharp.
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Thanks, Cadillac, I wish I had posted this earlier because had I known I was going to have to change to 3/8'' tooling I would have kept the AXA.

Someone told me the same about putting a level on the ways and running the carridge back and forth. I thought that was just too easy of a solution. will be doing that sometime today or tomorrow. thanks
 
markba633csi said:
Beginners seem to have more trouble with insert cutting tools than anything else. Do yourself a favor and get a small bench grinder and some HSS toolbits and grind your own tools the traditional way. Or, if you simply must use inserts, try to find some high positive rake types. They give great results on small lathes, comparable to or better than sharp HSS tools.

I have a small lathe also and like to use Kennametal CCGT 3251 style high positive inserts, with a homemade holder
They are diamond-shaped with a hole in the center. You can often find them on Ebay. Two flavors to look for are:
KC5410 for aluminum and other non-ferrous metals, can also be used on steel
KC730 for steel and stainless, can also be used on non-ferrous
-Mark
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Hi Mark, I have an 8'' bench for quite a while now as a am a woodworker for years, along with being a grease monkey.
I got the metal bug now. grinding sounds great as has been said to me by a few members already. Thanks so much for the info and direction, Jay
 
mikey said:
I use the cross slide as a platform for the level and, at least in my experience, it is more accurate than using blocks on the ways. I can get my lathe leveled within a few tenths this way and I can get it the rest of the way, to zero, with a 2-collar test.

It works.
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Thanks Mikey, now I just need some cutters so I can make a test bar and 2 collars. LOL
Also, I was trying to find your article on grinding tools that someone suggested, could you please send me the link as I can't find it. Thanks, Jay
 
Hey Guys, I know I replied to all of you but I don't see my replies. I want you all to know that if for some reason you don't see a reply it's probably something I did wrong. Please let me know if you don't see a reply to your comments, and I will respond again, and thank you all for your HELP!!!, Jay
 
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