Wells Index 847 Milling Machine

[Provincial]

I bought a Wells Index 847 milling machine off Craigslist in August. I only now have it up and running, but not installed in it's permanent location. I operated it under power before the purchase, so I knew that it operated well.

It was being run on a VFD that wasn't included in the sale. Fortunately, I have 3-phase power and the seller had kept the 480V controls. I had to replace the fuses and heaters so it would run on 240V.

I installed a DRO kit that I bought off Ebay. It seems to work very well, and is probably the same kit sold by Grizzly and others for more money. The manual is in Chinglish, so it is nearly worthless. It had no installation instructions, so I looked at directions on the internet and adapted them to this system.

The machine came with the vise in the photo, a 1-1/4" end mill holder with an end mill in it, 1/2 and 3/8 collets, and various end mills, boring bars, and stuff. Not bad for $1,000.00 loaded on my trailer, and only 8 miles from home.

It isn't new, but is doesn't have much wear except for the X-axis lead screw, which has .180 backlash in the worst spot. I have plenty of R-8 tooling already, rotary table, dividing head, and other tooling, too.

This will be a fun toy, about 1,000 pounds heavier than a Bridgeport.

The third photo shows my installation of the Y-axis scale.

 

[larry_g]

Maybe you'll get lucky like me and find the lead screw nut loose, as in not tightened down in place. That is a good looking machine.

lg
no neat sig line

 

[MushCreek]

I love Index mills- built like a tank. I think they're still around, so you might be able to get a lead screw. Check to make sure everything is tight and properly adjusted first, though.

 

[Provincial]

The backlash is twice as much in the middle of the travel than at the ends, so I'm sure there is a lot of wear in that area. For now I'll just pay attention to keeping the tool working against the screw and use the DRO for locating.

I've located a source for threaded rod to splice into the old screw. I might go that route.

Thanks for the encouragement.

 

[Oregon rock crusher]

Nice looking machine Provincial. Wells Index is a pretty good choice for a BP style verticle and 1k is a damn good price. I almost bought one once but I think it had a cat 40 taper. Good that you have plenty of R8 tooling for it and it is super easy and cheap to find more when needed. They definitely expand the range of work you can take on in your shop. congrats. Ed.

 

[Provincial]

Thanks Ed! The Cat design tooling is harder to find, and not cheap like R-8, but it is a stronger design and better for heavy work. Not a reason to turn down a machine, unless you don't need the strength, and/or have the R-8 tooling.

This mill was at Cross Creek Golf Course.

 

[Oregon rock crusher]

This mill was at Cross Creek Golf Course.

Well that's pretty close to me. I'm just over the hill near Buel. I often see carts and occasionally mowers for sale there but didn't know Tim was holding out any machinist tools. I'm kind of loaded up on milling machines now anyway and really should thin out a few. Glad you found it. Ed.

 

[metlmunchr]

You can pretty safely assume there's no wear on the screw at the extremes of travel, so that indicates roughly half the wear is in the screw and half is in the nut.

The screw is 5 pitch like other US made turret mills I assume, so you've got .100" of material and .100" of space from one point on a thread to the corresponding point on the next thread. If half the wear is on the screw, then what you have left in the most worn area of the screw will look about like a razor rather than an acme thread and the threads in the nut will look similar. I've made several screws and nuts for mills and a bunch of crossfeed screws and nuts for large lathes, and this isn't unusual.

You really should replace the screw and nut before using the mill much, especially in the power feed mode. If a piece of the remaining thread breaks off in either part, it can jam the screw and nut together to the point where it takes hours to free them up and get them apart. Had that happen in the past and its no fun at all.

Best source I've found for the materials is Green Bay Manufacturing in Wisconsin. They have most every imaginable diameter and pitch combination up to about 2.5" diameter. Its best to use the 4140 rod as the finish is super slick to the point where it looks like its been polished. The hardness is around Rc 28-30 so it machines nicely for doing the work on the ends. http://www.greenbaymfgco.com/ACME-threaded-rods.php

Green Bay also makes various acme nuts in a number of different configurations and materials. You just have to look and see how Wells made their nut and decide whether its easier to take a stock nut and modify it to fit, or just make the nut from scratch. Either way, 660 bronze will work fine. No need to go to difficult to machine materials like aluminum bronze as the loading isn't high enough to require it. Sometimes you have to use some ingenuity to figure out how to replace the nut as most of these types of mills have the X and Y nuts combined in one casting. A couple times I've been able to bore out the original nut and thread the hole, and then chase a matching thread on the OD of a standard available nut, and use red loctite to assemble it. Just depends on how the parts were made originally, and I've never done this for a Wells Index mill.

Since its obvious the nut has significant wear, it would be mostly a waste of time to replace the screw without replacing the nut as the worn and distorted thread form in the nut will begin to eat on the new screw immediately.

Green Bay's website doesn't have prices listed but I've found them to be far more reasonable than any other supplier for similar quality products. They also sell by the foot where most others like MSC or McMaster sell in standard lengths that tend to go from a little too short to way too long for an X axis screw in a full size turret mill. Their selection of nuts is more extensive than any other mfgr I've found as well.

 

[larry_g]

You can pretty safely assume there's no wear on the screw at the extremes of travel, so that indicates roughly half the wear is in the screw and half is in the nut.

The screw is 5 pitch like other US made turret mills I assume, so you've got .100" of material and .100" of space from one point on a thread to the corresponding point on the next thread. If half the wear is on the screw, then what you have left in the most worn area of the screw will look about like a razor rather than an acme thread and the threads in the nut will look similar. I've made several screws and nuts for mills and a bunch of crossfeed screws and nuts for large lathes, and this isn't unusual.

You really should replace the screw and nut before using the mill much, especially in the power feed mode. If a piece of the remaining thread breaks off in either part, it can jam the screw and nut together to the point where it takes hours to free them up and get them apart. Had that happen in the past and its no fun at all.

You are correct in what you say however Wells-Index ; http://www.wells-index.com/vertical-milling-machines.php , is still in business and the 847 is current production so checking with the mfg for parts would also be called for before making a decision on how to fix this machine.

lg
no neat sig line

 

[Provincial]

Thanks metlmunchr! I'll check Green Bay out.

The nut is a casting that has a flange for bolting to the saddle. I'll check to see if there is enough meat to thread a bronze nut in there. The nuts are still available from Wells Index. so that is an option. Another option is fabricating a new nut from steel, since steel allows a thinner wall thickness to accomidate the bronze nut.

OEM parts may be a better option when all factors are considered.

 

[22george]

I bought the gears that raise and lower the knee on my 847 from Wells-Index. They were cheaper than anywhere else I could find on the web that sells 847 parts. The people at Wells-Index were great to work with.