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vikingsword
12-20-2009, 05:10 PM
Hello all! I'm new here, and fairly new to the world of machining. I have a benchtop grizzly 9729 lathe/mill/drill that I use for fashioning guards for my custom knives but want to start machining lots more. In my endeavors in trying to make this machine as accurate as possible, I've aquired the gages and indicators needed, but I first want to start with a good machinist level, but I've noted that they come many lenths. So my question is, what would be the best length for my machine having a lathe bed of 31 inches? Regards, Wes

Davidhcnc
12-20-2009, 05:25 PM
Hi Wes
You do not need to level your machine.

uncle pete
12-20-2009, 05:56 PM
In reality you don't need a precision level, All they do is give you an indication of the twist or lack of, In the lathe ways. They do speed up the job but even after precision leveling a lathe bed you still need to adjust your shims or whatever other method your useing to take the twist out of the lathe bed. Measureing a test bar after useing the lathe to cut it between centers is still the final step as the lathe is checked under working conditions. I own a very expensive Mitutoyo level and still have to adjust for real world working conditions after useing it.

Pete

vikingsword
12-20-2009, 06:39 PM
Thanks guys! I have so much to learn. My dad, a master machinist, lives in northern Illinois, while I'm in Alaska. One of those times when I'd wished I'd taken the time to spend more time with him and learning from him.
Someone just recently gave me a cased set of Starrett indicator holders with a few pieces missing and slight corrosion so I have sent it back to Starrett for refurbishing and replacing of missing components. I' gonna enjoy using this set. WES

Black_Moons
12-20-2009, 06:55 PM
I have one of those precision levels.. cost me $100 and I think that was to much money. I show it off to people more then I actualy use it.

wierdscience
12-20-2009, 07:11 PM
I have one of those precision levels.. cost me $100 and I think that was to much money. I show it off to people more then I actualy use it.

Finally someone who is honest about they're level usage.:)

oldtiffie
12-20-2009, 07:21 PM
The key word/s here are "bench-top".

If the lathe is stiffer than the bench and/or if the bench is flexible and/or is loaded/unloaded periodically, and/or is not fixed rigidly to the floor/slab, all or most "leveling" may be to no avail.

Just set it up with a good (0.5mm/metre = 1/2,000 = 0.003 degrees = 1.7minutes) aluminium box-section machined all-over Carpenters level as well as you can.

Do as well as you can and see how the lathe performs. Absolute accuracy is NOT required. It only needs to be just a bit better than your work normally requires.

Same applies to any tool or machine.

Your Old Dog
12-20-2009, 07:43 PM
I have a 6" precision level that I enjoy using a bit. I don't use it so much as a level but as a comparator.

Understand that your lathe could be boltet do your wall vertically and still work just fine. The leveling that is important if across the ways from your gut to the wall. If both the left and right ends of the ways are not in agreement (level) the a full length piece of rod that has been worked from end to end will be thicker at the ends and thinner in the middle. That's why it's important to get your bed level so that no twist exist in the bed.

Mcgyver
12-20-2009, 08:14 PM
Finally someone who is honest about they're level usage.:)

hehe, for $100 they are definitely worth grabbing, they'll sit in their drawers for most of their lives and then bang, you need it and its there. I agree though it should be an acquisition of opportunity, not something on the must have list.

All my machines are leveled to one degree on another, most at the mechanic's level level of accuracy if only for coolant flow and the lathe of course gets the master precision level treatment in an attempt to remove twist. Recently I've been using my master precision level a lot in the area where they really shine; scraping machine tool ways

pcarpenter
12-20-2009, 09:20 PM
It's true that some of the little lathes don't need much in the way of levelling as their weight to rigidity ratio is such that they pretty much can't twist themselves even if on a not-so-level footing. I have one of the little 7x14 mini-lathes and this is one of the assets of these little lathes.

However, if the bed on your lathe is really 31" long, I would suggest that levelling it is a wise idea. The premise of levelling is not to make the machine level (in most cases). Rather, in most cases, establishing level from one end to the other is a way of insuring that there is no twist in the bed. Twist is a souce of variable error along the length of the bed.

The length of the level is not a big issue. The premise is that it is set on the cross-slide and then moved from one end of the bed to the other, checking for change as you go (often using parallels to avoid features on the surface). As such, it's got to be short enough to fit on the cross slide and not hit in the rear, in the case of a combo machine like that. Most of these precision levels are either 8,10 or 12".

I have a cheap import level and consider it adequate even though I borrowed one of the 12" precision Starrett levels when I set up my larger lathe. The lathe does not have to be absolutely level, but does need to reflect the same amount of "tilt" from one end to the other. As such, the level doesn't even have to be perfectly calibrated....just consistent.

paul

JRouche
12-20-2009, 10:50 PM
Hello all! I'm new here, and fairly new to the world of machining. I have a benchtop grizzly 9729 lathe/mill/drill that I use for fashioning guards for my custom knives but want to start machining lots more. In my endeavors in trying to make this machine as accurate as possible, I've aquired the gages and indicators needed, but I first want to start with a good machinist level, but I've noted that they come many lenths. So my question is, what would be the best length for my machine having a lathe bed of 31 inches? Regards, Wes

To answer your question. The longest precision level that you can afford. The longer of the same manufactures model is better. Thats why they go up in cost the larger they go.

Now back to reality. IMO you dont need one. None of us do. I have a few starretts in a few lengths up to 15". I got them for a penny on the buck.

So during my leveling of my lathe I tried some of my hardware store long levels, you know, the long I-beam aluminum construction levels.. Just to see if there was any gain by using the precision level. My own lil test.

The long levels worked great for the length of the bed. But the starrett level showed better on the short side, front to back.

But does that make the lathe cut any better? Hell no!!!!!

I am on a concrete floor which is plenty flat for my use. Heck, I think I could toss the lathe on a gravel bed and still make the cuts I am capable of.

The limitations for accuracy for me cant be contributed to the lathe or its setup. Ill take all that weakness. My skills dont come close to the limitations of the lathe. No matter what base its on.

But I do love tools. So I grabbed up some nice levels just cause. Not to make me a better machinist... That only comes with time.. JR