G4003G tooling

ryno85

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I've just upgraded from a Harbor Freight 8x14 to a G4003G. I never had any decent carbide tooling, but I've been looking to buy some for the new lathe. I did have some 1/2" HSS before which I've put in the tool holder and set to the center line, and it looks like there would be enough room to use 5/8" tools, but just barely. I wanted to see what everyone else is using.

On a related note, I can't drop the tool holder all the way down without unscrewing the knurled knob so far that the locking nut almost comes off. This doesn't seem normal, like maybe the stud is too short. Does anyone else have that issue?
 
The 5/8" tools could also be ground with the cutting edges below the outside 5/8" dimensions, and it is also possible to mill the bottoms of the tool holders shorter. The studs are usually threaded in quite deeply. You might be able to pull the stud out, clean out the threaded hole and the stud to get rid of any oil, and then Loctite the stud in with it not screwed all the way in. That would give you more height for the knurled nut.
 
I think I'll probably just stick with the 1/2" tooling. I'm trying to not modify anything on this lathe. That's part of the reason I bought it; I spent more time modifying the old one trying to get it to work well than I did actually using it.
 
I think I'll probably just stick with the 1/2" tooling. I'm trying to not modify anything on this lathe. That's part of the reason I bought it; I spent more time modifying the old one trying to get it to work well than I did actually using it.
1/2" tools are more than adequate for your lathe. The BXA "XL" holders can hold 3/4" tools, and the bottom of the slots are lower than the other holders. Those holders would hold your 5/8" tools, if you have any. If not, it is probably not worth buying any, the 1/2" tools are plenty rigid enough. The real advantage is to be able to fit other tooling bought used at good prices. FWIW, I am using some 3/4" insertable tooling with BXA XL holders on my 13x40, and I find them much more rigid, and the extra mass seems to help stop vibration and chatter. They are also often cheaper to buy used than smaller ones.
 
I finally got my 220v outlet finished today and had a chance to run the break-in and make some cuts using the 1/2" HSS tooling I had. Like you said it definitely seemed rigid enough so I'm going to just stick with 1/2". What style of inserts are you using? I've been looking at CCMT. I'd really prefer CNMG or WNMG since you get more cutting edges on each insert, but from what I understand these "smaller" lathes don't have the power for those inserts.
 
CNMG and WNMG are usually used in negative rake tool holders so you need power and rigidity to use them to full effect. The CCMT/CCGT inserts are positive rake inserts intended to cut with lower cutting forces so they work better on smaller lathes. Most of the CCMT grades will work with steels at about 200 sfm so your lathe can hit the speeds they require until your work piece diameter dips below 1/2" or so. With the CCGT's, you need speed and you won't hit it unless your work piece is about 1-1/2" or so but I've found that even at lower rpm's, the serious positive rake of the CCGT's cut pretty nicely.

AR Warner also sells CCMT inserts in HSS if that interests you. I haven't tried them yet, though.
 
A few thing to consider, although CNMG and WNMG have more edges, does it really make a difference in the long run at the hobbyist level? A CCMT insert can last me 3-6 months and I pick them up for around 2-6 dollars each. As Mikey outlined, the negative rake tool holders in general do not perform as well in small lathes with less Hp. There is also a wide range of inserts with different coatings and edge profiles, so although the holder may be negative or neutral rake the insert edge can be highly positive. In addition, usually the larger the insert holder, the wider availability of inserts, they are much more plentiful and less expensive on different auction sites. Do not buy generic no-name inserts like Cobra, etc., they are cheap and they do not last. I buy name brand inserts such as Kennametal, Iscar, Korloy, etc. and they work much better. But you need to know a bit about the insert types, coatings and profiles. The cutting speeds are more for production level machines, I routinely run my inserts at 1/4-1/2 the rated SFM with great finishes and no cutting issues. Part of this is also the rigidity of your lathe/holder. CCMT insert holder is considered a neutral holder (second letter defines the holder rake), WNMG insert holder is negative.

My everyday insert for cutting steel is a CCMT, and I use both CCMT and CCGT inserts. For softer materials I use a WNMG holder with highly polished uncoated carbide inserts with a sharp positive edge. They cut great, I usually change the cutting edge every 2-3 months so an insert lasts a long time. If one breaks, takes no time to replace it and I do not need to reset my tool holder position or DRO position setting. I have a wide range of other insert holders for different profiles, all my other insert holders are neutral "C" type holders which seem to work well on the lower power lathes. I use different inserts depending on the material, the depth of cut and the type of cut (heavy, light, interrupted), but usually for my CCMT I usually use a single insert type (from Kennametal) that has a wide cutting performance in most materials. I have attached some notes I put together.

The G4003G should be able to take a BXA holder, so 5/8" tool holders would be more optimal if it fits. If you had a 13 or 14" swing you could use 3/4" holders which can give a bit more rigidity providing your lathe is also more rigid.

On the QCTP holders you should have enough adjustment for the full adjustment height on the tool post, it might be the brand you have. Otherwise make your own threaded adjustment posts that are taller.
 

Attachments

  • Lathe tool holders and inserts recommendations.pdf
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I am assuming your tool post is BXA because you are having trouble getting the 5/8" tools low enough. The 4003 lathes are sort of on the borderline between AXA and BXA fitting from what I have read, no personal experience. All my insertable tooling is triangular, TPG, etc. I would like to get some CCMT tooling, but do not seem to need it very badly so am waiting for a great deal before buying.
 
Thanks for the responses everyone, especially mksj for the document. All these different insert types are pretty overwhelming. I guess once you find the one that works for you it's just a matter of finding the best price.

I think I'm going to go with a 5/8" CCMT tool. My toolpost is the BXA that came with the lathe. I was going to be making some more tool holders on my mill, so I can just mill the slot a bit lower if needed.

Any recommendations for a threading toolholder? I see there are two types; one holds the bit flat and the other vertical. Is one better than the other?
http://www.shars.com/1-2-rh-mtvo-tri-lock-tool-holder-1
http://www.shars.com/products/index...ool-universal-external-threading-toolholder-1
 
A G4003G with BXA should be able to use 5/8" shank tools just fine without any modifications needed. My PM1236 can even use 3/4" shanks with oversized holders.

What brand BXA tool post & holders are you using? Can you post a photo of your issue?
 
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