Grizzly Lathe Opinons

[Caroline]

Hey Everyone-

GRT has saved up all of our milk money over this past year and we are now looking to buy ourselves a brand-spanking new lathe. We're considering buying a Grizzly Lathe, shown here, but we have no idea as to whether this company or their machines are reliable and will take the beating our team is sure to give it.

If anyone has comments or experiences (positive or negative) with Grizzly lathes or Grizzly tools in general, please share with us. If you would like you can email comments to ebruhis@gunnrobotics.org . Thanks!

Sincerely,
Caroline
Gunn Robotics, Team #192

[Andy Brockway]

I have not had any experience with the Grizzly but this link discusses most smaller lathes.

http://w3.uwyo.edu/~metal/makers.html

A search for home metal working will give you additional sources.

Good luck!

[Matt Reiland]

I bought my own machine for my basement, and got a Smithy 1220XL Ltd with CNC upgrade package. It is cheaper than the one in the picture also it is a 3-in-1 machine, a mill, drill press, and lathe. What is your budget? For $5000 you can get a CNC 3-in-1 machine that will do just great, otherwise (If I only knew then what I do now) buy it used. Most of these larger machine tools last 30 years easily. Some of the machinists here have bought equipment like bridgeports from places like plastic prototype shops with little if any wear on a 1 or 2 year old machine for pennies on the dollar (Its all written off from the original owner)
One of our schools just bought an Emco CNC machine which is really slick and includes a protective shroud to keep people from getting hurt

[Lloyd Burns]

The only metal lathe I found on the grizzly site was a 7" x 12" machine. There are two things you want to check: quality and size.

There are a lot of these machines imported into North America, made across the Pacific, in many cases. Some of them are excellent sources of rough castings to make a lathe, and preassembled to save including instructions on how to assemble them. The ground surfaces on some need filing to break the really sharp "flash", and the slides need to be checked that they don't tighten as you screw them from one end to the other. Gearboxes may leak a treat around the shaft ends, once 'home' and filled with oil. Your example has inch and metric dials - but the threads for the slides are one or the other, and the dual dials are hard to get used to.

As to size, in your 7" x 12", the first number is the outside diameter of the largest workpiece that will fit over the ways below the chuck, but this is not usually machine-able, because the tool must be held by the holder mounted on the saddle: to machine close to the chuck, the saddle must slide under the workpiece, or the tool must extend around the outside of the work.

If you wanted to bore a hole in a disc, the jaws of the chuck would probably have to hold it on its outside edge, and if the radius of the disc and the length of the jaws' upper step exceed 3.5", the jaws will hit the ways.

This 7" diameter might not be big enough for some of the things you might want to do, but it be ok for much of what you need to do, though you may need to have access to outside machining for a few bigger pieces.

The 12" distance from head to tail stock may not allow much more that 10" of useful length. If you were trying to turn the end of a shaft longer than that, the diameter of the hole in the headstock spindle (which turns the chuck) limits the maximum diameter of the shaft. It might get cramped in there.

You pays yer money ...

As Matt points out, used equipment can be a good deal, if you have someone with experience to check out the 'gem' you are considering. You may even find auctions in your area, and you might get a bigger machine for the amount you have to spend.

You've probably seen some of the "equipped" teams with machines like these at First events: my guess is that these are what they could transport, that they usually use much bigger machines before the "ship date".

And new or used, buy as many accessories as you can afford when you buy your machine, because they may not be available for your machine when you need them, down the road.

Another machine tool you might consider is a mill: there are many small, inexpensive mills out there, looking like reinforced drill presses with a long moving table for your workpiece. Used on workpieces that are non-cylindrical, they can make flats and slots (even key-slots in some shafts), and make sides of things parallel.

[dlavery]

Caroline -

Like (way too) many things in life, a reasonable answer to your question must be based on how you answer this: how much are you willing to spend?

Here are a few things to think about before you buy your lathe.

- Many of the lathes sold by Grizzly, Harbour Freight, Enco, MSC, Smithy, and others as "their" brands really all come from the same sources, and they just stick their labels on the machines. Most of the lower-end lathes and mills come from either Taiwan or China. Find out where the machine was made - there is a BIG difference in quality. Many of the Taiwan imports come from Rong Fu, and are good, solid machines (high quality castings, good precision on the ground surfaces, solid pulley/gear covers, etc.). Many of the Chinese import machines tend to be copies of the Rong Fu designs, but with lower quality (blowouts in the castings that have been filled with Bondo, flat grinding on the lathe ways with no oil-retention scraping, cheap sheet metal covers, etc.).

- Buying your lathe is only the beginning of the investment. Unless you know how (and have the time) to make all your own tooling, plan on spending AT LEAST as much as you spend on the lathe for the additional tooling you will need. Things like backplates, 4-jaw chucks, cutting tools, tailstock chucks, free centers, collet sets, tool post fixtures, center indicators, tailstock die holders, cutoff tools, toolpost grinders, knurling tools, etc. all add up fast.

- Make sure you know (or can find someone who knows) how to set up the machine. It is not as simple as opening up the crate and tossing it on the stand. The lathe has to be mounted on a VERY solid support (think about really big slabs of concrete), and preferably bolted to the floor. To get good performance and precision, it must be very accurately leveled in all dimensions, and the lathe bed checked carefully for twist and spindle alignment. This is a straightforward process if you know what you are doing, but probably not something you want to try if you have never seen it done before.

- If you have someone on your team that knows what to look for (any retired - or active - machinists on your team?), consider buying a used lathe. If you know what to look for and can avoid getting scammed, you can get some great deals on used machines. I picked up the 12x27" lathe that I have in my shop as a used machine for 20% of the original purchase price, and all the basic-to-moderate tooling came with it. I knew the person that owned it, and knew the entire history of the machine, so it was a good deal. eBay has some nice deals, but be sure it is a machine that you can inspect before final purchase.

- If you can, get a lathe with a quick-change gear box. Most of the larger models have them. You will save yourself lots of time and frustration associated with dealing with change gears if you get this option (and save a lot of re-training time as student operators change from year-to-year; it is a lot faster to teach someone how to use the gearbox than it is to teach them how to change the gear sets).

- Same thing for the toolpost - get a quick-change version if you can, and one that allows easy adjustment of the tool height. It will make life much easier.

- As a general rule, bigger is better. Get the largest lathe you can afford and fit in your shop. The larger machines will have larger chucks and spindles, hence a larger rotating mass during cutting operations. The larger rotating mass acts as a big flywheel, making for smoother cuts. The larger machines also provide more rigid support for the toolpost and tooling, reducing chatter.

- I know I will get some disagreements here, but I recommend you stay away from combination machines (lathe/mills, lathe/mill/drills, etc.). In my experience (and that of a lot of people I have talked with), these machines are designed to do too many things and to cost too little for the careful design they really need. As a result, they don't do anything really well. I have never been happy with the accuracy or precision of any of the combination machines I have used.

There are lots of on-line resources and discussion groups you can use to find out more information and get a lot of help (both before and after you buy). Here are a few resources to check:

7x10minilathe - Yahoo Groups board for owners of the Chinese 7x10 minilathes marketed by Harbor Freight, Grizzly, etc.

9x20Lathe - Yahoo Groups board for owners of the imported 9 x 20 Lathes sold by Jet, Enco, Harbor Freight, and others.

Bench Mill/Drills - Yahoo Groups board for owners of metalworking mill/drills made by Rong Fu and the knock-off clones (but includes a lot of discussion on lathes as well)

Machinists's Workshop - check the "general" board for info on lathes and other tools

Metalworking Web Sites - good index of metalworking tools and suppliers, with lots of links to additional information and resources

-dave

[Jeff Rodriguez]

I know our school bought some grizzly machines, a planer, sander, and something else. The teacher loves them and uses them all the time. He says they're quality machines. thats about all i know about them.

[Matt Reiland]

Caroline,

Maybe you could post a little more info on what you want to do with the lathe and it may help some of the people recommend one to you.

dlavery: I agree that a $3000 3in1 can't hold the tolerances that say a $25,000 bridgeport can but I definately won't go way out on a limb and say they are totally junk, especially if you don't have the space or money for a 2500lb professional machine (with gigantic concrete slabs!!! mine sits on a Craftsman professional 1500lb platform). If the machine caroline is looking for is used for 'light duty' with reasonable precision especially for a first robot, many of the smaller machines could do it. Many people are impressed with the parts my CNC machine cuts out of aluminum, while they may not be perfect they are more than good enough for our First robot and soon to be Battlebot.

See you knew somebody would comment

[Caroline]

Matt-

We mainly machine aluminum and plastic on our lathes, and the stock is usually a small diameter (under 2"). However, there are the instances when we need to machine steel and larger stock. Our machines are put under an unusual amount of abuse, seeing as we have 50 student members.

In terms of quality and precision, one thing I found with tools in our shop is that many times we design parts based on the quality of tools we have. For example, before 2001 we would never design a part that needed very precise milling done on it. However, we bought a new bridgeport mill in 2001 and suddenly the parts we designed had much lower tolerances, since we knew it was now feasable for us to machine the part.

The hard thing is that we are unsure of our budget as of right now. Our fundraising efforts have just started, so we're unsure of the amount of money we want to spend. However, if we can find a good, reliable machine for a reasonable price we'll probably look to buy it.

-Caroline