Index 747 Mill Opinions?

[landrand]

Was wondering what the experts think about this mill that is for sale in my area? It's an Index 747 mill, variable speed, 230v 3ph, comes with 6" machine vice, #20 taper holders, collet chuck with collets. The seller is asking $2,500. I'm a newbie and think it would be fun to have one of these in my shop to play around with in my retirement.

Unfortunately, I don't know anything about these mills and I'd be buying it without any expert knowledge of what issues/problems to look for upon inspection. Any advice or recommendations would be greatly appreciated.

 

[eKretz]

They are good machines. I have that one's slightly bigger brother, an 847. And that's a QC30 taper, BTW.

Things to look for are going to be difficult if you're not very knowledgeable about the machines. I would run the spindle and listen. Should be pretty quiet and smooth. Check that the speed adjustment works well and that both low and high range work well. Run it at high speed for a while and see if it gets hot, stays cold or is warm. Should not get above 120° F. If it doesn't at least get warm to the touch, the spindle bearings probably don't have enough preload and may need replacement.

Some guys worry about backlash in the screws, that doesn't really bother me much, but it can give you an idea of the amount of use the machine has had if it's still on the original screws and nuts. Table way and gib wear is an important one but those are not super easy to check. Are you familiar with dial indicators? Got one with a mag base?

 

[landrand]

They are good machines. I have that one's slightly bigger brother, an 847. And that's a QC30 taper, BTW.

Things to look for are going to be difficult if you're not very knowledgeable about the machines. I would run the spindle and listen. Should be pretty quiet and smooth. Check that the speed adjustment works well and that both low and high range work well. Run it at high speed for a while and see if it gets hot, stays cold or is warm. Should not get above 120° F. If it doesn't at least get warm to the touch, the spindle bearings probably don't have enough preload and may need replacement.

Some guys worry about backlash in the screws, that doesn't really bother me much, but it can give you an idea of the amount of use the machine has had if it's still on the original screws and nuts. Table way and gib wear is an important one but those are not super easy to check. Are you familiar with dial indicators? Got one with a mag base?

Yes, I believe I have a dial indicator and mag base. I've slowly been picking up machinist tools at garage sales, antique stores through the years and probably have one sitting here somewhere.

I'll do some research on youtube to see if anyone out there has a video on how to check the soundness of a vertical mill.

 

[GregSY]

Excellent machines....that looks like a late production units as it has the later variable speed head on it. Your photos, of course, suck so it's hard to make any better assessment. If it is in good shape, it's a great mill.

 

[eKretz]

You can do a quick and dirty assessment by running the table to one end, and setting the dial indicator so that it's mounted on the saddle and registering on the table near the end of the saddle. Then grab the longitudinal axis handle or table itself at the end sticking out farther and pull away from and toward the machine (fore and aft, not side to side). Note the indicator readings at both extremes and get the difference. Then run the table to the middle and do it again. Then run the table to the other extreme and do it again. Compare those numbers derived from the indicator readings. If they're close to equal at all the places it's probably in real good shape. I'd expect to see up to a few thousandths difference on a machine in decent shape.
If you've got .030"+ difference it's extremely whipped. Likely will fall somewhere in between. You can do the same thing on the in/out axis by repositioning the indicator to suitable location and running the same tests.

 

[landrand]

You can do a quick and dirty assessment by running the table to one end, and setting the dial indicator so that it's mounted on the saddle and registering on the table near the end of the saddle. Then grab the longitudinal axis handle or table itself at the end sticking out farther and pull away from and toward the machine (fore and aft, not side to side). Note the indicator readings at both extremes and get the difference. Then run the table to the middle and do it again. Then run the table to the other extreme and do it again. Compare those numbers derived from the indicator readings. If they're close to equal at all the places it's probably in real good shape. I'd expect to see up to a few thousandths difference on a machine in decent shape.
If you've got .030"+ difference it's extremely whipped. Likely will fall somewhere in between. You can do the same thing on the in/out axis by repositioning the indicator to suitable location and running the same tests.

Thanks for the info.

I haven't physically looked at the machine yet as it's about an hour drive away from me. I'm trying to get up to speed educating myself about how to check on the condition first before I go look at it..

I understand that Wells Index is still an operating company in Michigan so I am assuming I would still be able to order parts. I need to check with Wells Index about that. If it needs new spindle bearings, is that something I would be able to replace myself or is it a difficult job to do for someone not familiar with vertical mills? I think it would be fun to refurbish one of these old mills and get it back into tip-top shape.

 

[eKretz]

Thanks for the info.

I haven't physically looked at the machine yet as it's about an hour drive away from me. I'm trying to get up to speed educating myself about how to check on the condition first before I go look at it..

I understand that Wells Index is still an operating company in Michigan so I am assuming I would still be able to order parts. I need to check with Wells Index about that. If it needs new spindle bearings, is that something I would be able to replace myself or is it a difficult job to do for someone not familiar with vertical mills? I think it would be fun to refurbish one of these old mills and get it back into tip-top shape.

Yes they are still making and selling machines. Parts are available. The spindle bearings can be replaced fairly easily by someone who is competent enough. Do some reading and you'll find all the info you need here as well as references to some helpful reading material. If you would even think about using a hammer, don't attempt the job.

 

[GregSY]

The odds the spindle bearing are bad are very low.

 

[eKretz]

The spindle bearings don't often necessarily go "bad" per se. But they certainly do wear enough to lose a bit of preload. I've replaced plenty of sets of bearings on Bridgeports over the years, as well as my own Wells Index. Most ops are fine, but with a loss of preload you'll start to hear a bit of chatter on larger cutters or buried endmills, etc. They don't have a whole lot of preload to begin with.

 

[landrand]

One other question. The Index 747 mill comes with #20 Taper Holders according to the ad. I talked to Wells Index and told them the mill has #20 taper holders and they didn't think that was correct. They said the machine would either have R8 or #9 Brown & Sharps. I'm new to mills. Can you explain to me what the #20 is and if this is good or bad? Thanks!

 

[eKretz]

One other question. The Index 747 mill comes with #20 Taper Holders according to the ad. I talked to Wells Index and told them the mill has #20 taper holders and they didn't think that was correct. They said the machine would either have R8 or #9 Brown & Sharps. I'm new to mills. Can you explain to me what the #20 is and if this is good or bad? Thanks!

As I already mentioned, it's not 20 taper. It's QC30. Whoever is selling it doesn't know what they're talking about. Call Wells back if you want and ask them about QC30. It's an upgrade they offered at additional cost, good taper to have. I have it on my 847 also. Holders aren't as common as R-8 and cost a smidge more.

These use a nut on the bottom end of the spindle to push the tools into the taper by pressing against the flange rather than a drawbar to pull them in from the top. If the spindle has a through hole you can get a manual or powered drawbar and use NMTB30 or any drawbar 30 taper also.

 

[tnmgcarbide]

NT#30 taper could be likely . if that's the case...good.
the good news is they are more robust than R8 tooling .. though you can buy a
set of r8 collets for $100 . an NT30 tg-75 collet chuck would cost a bit more initially
though is going to be more rigid and can support things like shell-mill arbors and
larger endmills..
good luck .
the index is a fine machine in the spirit of the TREE , XLO ,k+t GORTON, and cinci TOOLMASTER ..

 

[jcwright87]

As I already mentioned, it's not 20 taper. It's QC30. Whoever is selling it doesn't know what they're talking about. Call Wells back if you want and ask them about QC30. It's an upgrade they offered at additional cost, good taper to have. I have it on my 847 also. Holders aren't as common as R-8 and cost a smidge more.

These use a nut on the bottom end of the spindle to push the tools into the taper by pressing against the flange rather than a drawbar to pull them in from the top. If the spindle has a through hole you can get a manual or powered drawbar and use NMTB30 or any drawbar 30 taper also.

I apologize that this thread is a little old but I'm not sure who else to ask. I have an 847 also and Wells told me that my model may have come with a saddle feed from the factory. The only thing left is the reversing gears on the knee. I'll attach photos. I have found some photos on lathes.co.uk, but nothing for model 847. Do you have any ideas where to look or who to ask for info? I'd like to source parts or at least learn something

 

[Bill D]

Best photos I could find in a quick search. This one claims a power feed on the knee. Looks like a servo brand power feed to me.
Bill D

Machines Used | Wells-Index 847 Vertical Milling Machine with Power Cross & Knee Feeds

 

[eKretz]

A while back I ran into a guy in Chicago that was closing down his shop and he had an old 747 with a similar gearbox on it, but on the'X' axis feed. Not sure where to look for any info if Wells doesn't have anything.

 

[4GSR]

That looks like the leftovers from their early attempt to add stepping motors on the mill for CNC control. Their early attempt was not a very good setup so many people stripped it off the mill and made it a manual mill. That doesn't look like any of the power feed units I've seen over the years. Get your serial number and call W-I and get the scoop on what you have there.

 

[GregSY]

Whatever it is, it looks OEM. The pics Bill posted are aftermarket add-on.

Here is a pic of a pulley-head 847 with the factory X feed....very stout but also bulky.

 

[4GSR]

Whatever it is, it looks OEM. The pics Bill posted are aftermarket add-on.

Here is a pic of a pulley-head 847 with the factory X feed....very stout but also bulky.

That's the same factory X-feed As I have on my 645 mill. Maybe a tad beefer.

 

[ratbldr427]

Somewhere along the line WI supplied Servo feeds. I have all the original paperwork for my 887 and it came with Servo's on all axis. So my guess is they discontinued the ones like on your picture. The spacer between the dial and machine I think is a W-I part but the Servo feeds and clones will fit. I don't think Servo made the spacer/adaptor .
Mine is just like the one in Bill D's post.