Milling machine purchasing help please

[T.Hoffman]

I am looking at buying a milling machine for home use. Currently at work I have been tinkering on an older Jet model that does NOT have z-axis table feed. So every time you want more clearance for putting in a drill chuck or working off my angle plate, I have to break the head loose and raise it up. What a pain.

I have been on the Jet website and have looked at some of their models that would fit my application. I was wondering if I could get some more opinions/options of what else I should be looking at for manual machines that have vertical table feed. Does Bridgeport make a smaller manual machine? Pros or cons of the Jet equipment is also appreciated.

New or used? How can I tell the condition of a used machine (besides appearance)? Is there a way of checking bearing wear? Table drive screws?

Thanks in advance for any help-

[This message has been edited by T.Hoffman (edited 11-05-2001).]

[C. Tate]

I have seen several Jet mills that are very nice and do not cost very much. I have a Sharp, Bridgeport and Excello. The Sharp is a import from tiawan and the only difference beteween it and the Bridgeport is some chrome on the ways and $5000. The Jets I have seen are almost identical to the Sharp and are probably an excellent choice for HSM. If you find an Excello buy it they ooutclass anything I have seen.

The world of used anything is a minefield. If you go to a reputable dealer they usually offer a thirty day return policy. If you go to someone's shop and the machine looks like crap it probably is. If it looks well maintained then it probably is.

Use an indicator to check the spindle runout.
Extend the spindle it's full length place indicator on the inside of the taper and pull on the spindle in several directions the spindle should not move more than .0005". Rotate the spindle it should have less than .0005" T.I.R. Check table play the same way put indicator against the table push and pull you should get less than .001" movement when adjusted correctly. Remember that gibs can be out if adjustment on the table which will give bad readings so take some tools to make adjustments.

Good Luck
Chris

[1erful]

I did some research, and with a little help from some "spies" on the inside, I then ordered a Grizzly G4027. It is on sale through an ad in HSM for $3795.00 or from Grizzly's Christmas catalog for $3895.00. If you order one be sure to give the ad number from the HSM ad. An interesting piece of information that I learned is that the factory that makes the Grizzly G4027 also makes the machines that are sold by a number of machinery catalog companys. They have a "M" in the front of the column and the knee. Some companies even paint the "M" in a contrasting color. WALT

[SGW]

Check out the used machinery buying tips at www.mermac.com.

What size are you looking for?

I've got a Jet JVM-830 (no longer sold). It's a pretty good machine, all things considered. There isn't anything about it that makes me annoyed when I use it. It would be nice to have a Bridgeport but...the JVM-830 is about 2/3 B'port size, which fits a lot better in my cellar.

Bridgeport may still sell the M-head B'port with Morse #2 collets, which is somewhat smaller than the "standard" B'port, but I'd get something with R8.

Jet currently sells a couple of smaller mills, the something-836 and the something-830, I think. Either of them would probably be good. Of coure, if you can fit in something larger, go for it!

One thing I have learned: machines that "look just the same" in the pictures but are of significantly different prices are NOT "just the same." There are reasons why one import that "looks just like" another is priced a thousand dollars more. Stuff you can't see that matters, like quality of bearings. So be wary of only comparing lists of features. Quality is elusive, but go for quality ahead of a long list of features.

Another thing to watch out for is monsterous table sizes on small machines. Some of the cheaper mills advertise this "feature." The machines aren't big enough to provide proper support for tables that big, so when the table is cranked to one end or the other they deflect significantly.

[Randy]

Walt's post brings up a question. I believe the "M" on the column means that it's made of Meehanite, a brand-name cast iron that's supposed to have superior properties of rigidity, vibration damping and whatnot. Does anyone know anything interesting beyond what's in their website? I'm looking for scuttlebutt here. Like, is there any problem with counterfeit Meehanite? (Counterfeehanite, maybe?)

[This message has been edited by Randy (edited 11-06-2001).]

[SGW]

Meehanite is a patented manufacturing process for cast iron (see http://www.meehanite.com/ ) that's supposed to produce a more uniform product, but I would hesitate to attribute any significantly superior properties of rigidity or vibration damping to it. One can also get high-quality castings without using that particular patented process and which might in fact be better suited to machine tool use, so I wouldn't necessarily consider "Meehanite cast iron" a benefit. It might be...but I don't think it's automatically so. For instance, a Meehanite casting may have a fine, uniform grain and be relatively soft. Those are nice characteristics if you're machining parts from it, but for your milling machine table you might do better functionally with a cast iron that was harder.

The fact that a company advertises "Meehanite castings!" may be more a function of the marketing department than anything else.

[JimH]

I have the smaller Jet Knee mill,JVM-836 (8 inch by 36 inch table). I too would like a good Bridgeport, but $ $ $ $ $ $ $

I am adding a motor to drive the quill feed and am planning on adding a VFD and 3 phase motor to expand the speed range.

For a good price check with Alley Supply Co. They are listed in HSM. Price usually includes shipping.

www.alleysupplyco.com

No association other than have talked to them about a new Jet lathe. Very helpful.
Jim

[T.Hoffman]

Thanks for the info tips.

I have looked at the Jet JTM-830 and JVM-836 series machines on their website (and spec sheets), but have not had a chance to see them up close.

I have heard that a manual Bridgeport will be coming available through work, but not sure of buying something used. But I know that machine hasn't got a lot of use over the years. hmmm.......

What sort of travel specs on the table and head are considered 'necessary'? I have talked to a guy at work who has an older Jet (not sure of model) that does not have enough room between the head and table to do some things.

I like the specs of the JVM-836 the best so far, but that is just on paper.

[SGW]

My JVM-830 has about 12 1/2" max between spindle and table. If I pile up a rotary table and the work and add in a drill chuck, it gets pretty tight. So far (in 16 years) I've always managed to find some way to get the job done, but it sure would be nice if I had a couple more inches in there. I keep threatening to make a riser block for the column, but I haven't done it yet.

The manual B'port would certainly be worth a serious look. I think the two Jet machines you're looking at are pretty good, but the B'port is definitely better. It's going to be better quality overall, the table is going to be bigger, it has power downfeed, and on and on. If you can fit it in your shop, and it's not beat up, I'd probably go that route.

[MR E]

I haven't heard anyone mention auctions.
With the economy the way it is there are a lot of machine shops selling out.I have been to several sale lately and I've seen B'ports mills with powerfeeds selling in the $1200 to $1800 range.The tooling and accesories are going just as cheap!