Looking for sealed tapered roller bearings

[Stan the Man]

Just a thought about spindle bearings based on machines that I have serviced. Wood molders, made in Germany. Spindle speeds 6 to 8,000rpm. Tooling: up to 9" long solid steel 5"+ in diameter unsupported on outer end. Heavier tooling is carried on out board bearings. Tooling end of the shaft has two angular contact ball bearings that come as matched sets and are installed so the pre-load stack of spring washers force them against their deep groove sides. Very heavy spring washers. The other end is supported by a single ball bearing that has a sliding fit to the housing allowing all heat induced movement to move that end and not the tooling end. All bearings on the lower cost machines ($100K) are lightly greased when installed and have no means of adding grease. The bearings are protected from dirt by metal labyrinth caps. No rubber seals. High speeds, large diameters and rubber generally don't play well. These are well balanced systems and will run for many thousands of hours before needing bearing replacement. Fairly expensive bearings! It takes some special tools and a 20 ton press to service them. High production machines use oil mist lubrication systems.

I'm currently waiting for motor spindle bearings to come from Italy for a 20,000rpm spindle motor on an automatic edgebander. Luckily we keep a spare set of motors on hand. Odd bearings and they are on back order!

Thanks Larry interesting stuff, can't imagine why you would need a 20K spindle speed on an edge bander unless its trimming off the excess width of the edge as in say a router spindle then it makes sense.

 

[Cadillac]

This is the only tapered roller bearing I’ve ever seen with a seal attached to it. I’m a maintenance mechanic and these have been in a box for a long time. Havent Come across where they would be used but they do make them. These are timken LM-67000L-A
Is there no room to install a separate seal?

 

[Ischgl99]

This is the only tapered roller bearing I’ve ever seen with a seal attached to it. I’m a maintenance mechanic and these have been in a box for a long time. Havent Come across where they would be used but they do make them. These are timken LM-67000L-A
Is there no room to install a separate seal?

View attachment 404011View attachment 404012

Timken has those in a very limited number of bearing sizes, and the seal is only on one side. It looks like those are only available in inch series as well. I’ve never seen one and not sure where they would be used, but the catalog has sizes up to 2.6875” bore. Maybe axle bearings? The way the seal is installed it is outside the bearing dimensions, so I’m guessing that does not conform to ISO sizing specifications and why the European bearing manufacturers don’t do that in the metric size bearings.

 

[homebrewed]

Hi Hb.
Thanks for your reply, looking back at what I posted I should have said Wet Dry rather then emery , I will do that use the wet dry. I agree covering the bed of what ever machine you grind on is important to keeping things from going south with grit. I have another larger lathe I can use to make the modified pieces for the 7 x 12. I think I will use the plastic cover as a working model then machine two aluminum plates to replace the plastic.

Its funny you mentioned a two piece cover as I was also thinking along those lines. However I want to explore your idea of creating a well or reservoir for grease. There would be more then enough room to access the back side of the bearing cover behind the mounting plate of the chuck, then its just a matter of smearing grease into the reservoir and putting it back into position. Great Idea !!!

I saw a guy add two threaded holes to the top of the case, one directly over each gear1/4 -3/8th dia. big enough to visually inspect the gears as well as add lube via gravity then made two brass plugs to close them up. Another fellow added a larger plate over the top of the case with a padded surface to lay tooling on. Perhaps a combination of both ideas would allow inspection/lube when needed and a larger surface to lay your chuck wrench or other items as found on larger machines. So many options. LOL.

What mods have you done so far and which ones would you still like to do?
Stan.

As far as mods I've done, in addition to bearings they currently are:

1. A plinth to replace the compound.
2. I added a crank to manuallly drive the lead screw. It is attached to the right end of the lead screw.
3. A DRO for the Z axis. It's mounted behind the bed. I'm currently working on adding one to the cross slide.
4. I replaced the right hand leadscrew bushing block with a version that uses thrust bearings to remove lead screw backlash. I made it with my mill.
5. I replaced the saddle gibs (also called slide plates) with solid gibs that are adjusted using shims rather than the OEM overly-fiddly jack screws.
6. A cover plate for the apron gears. While I had the apron removed, I drilled and tapped some M6 holes for a future DRO mount for the cross slide.
7. I replaced the cross slide nut adjusting arrangement with a double nut design similar to the type seen on anti-backlash nuts for ACME screws. The nuts are solidly bolted to the cross slide, using shims to get them properly aligned to the feed screw. I made the two nuts by cutting an OEM nut in half.
8. I totally worked over the tailstock, which started out life as a POS (unfortunately a common occurrence). That included turning the fixing screw that holds the base to the top around so it can be loosened from the top (making it MUCH easier to adjust the tailstock), and milling the base/top mating surfaces so the top is level and aligned to the bed, both horizontally and vertically. I also replaced the tailstock hold-down nut with one that is tightened using a tommy bar (rather than the more complicated camlock design). It's simple and much easier to use than a wrench.
9. While I had the headstock removed for the bearing replacement job, I also shimmed it so the spindle was better-aligned to the bed. It's a little fiddly because shims rotate the headstock around its rather short width, while you're trying to achieve a small value about twice that far away on the other side. I had to resort to a piece of .0005" shim in the stack to get it right.

The first 4 items were a suite, prompted by a ball-turning tooll I got for the lathe. It's pretty inexpensive but I paid a price for that -- it replaces the compound so it relys on moving the carriage in small controlled steps to turn balls. I did that by adding the handwheel and DRO (there went the "bargain" part of the ball turner ). The carriage is moved by closing the half nuts and turning the crank. And then I realized that the combination was ideal for using a much-more rigid plinth to replace the compound....so I made one. I scraped the plinth and top of the compound so there was plenty of contact for an even more rigid setup. I also scraped the top of the plinth so tool holders also would be well supported. I do still use the compound for some things like cutting threads, turning short tapers and sneaking up on ID's and OD's where I need very precise dimensions.

Item #4 was prompted by my observation that there was a huge amount of backlash when driving the carriage with my hand crank. It was caused by a lot of built-in clearance between the shoulders on the lead screw and the bushing blocks. It wasn't a deal-killer because normal turning operations will take out the backlash, but sometimes it made it difficult to sneak up on a dimension.

I owned and used my lathe for years before doing any of these mods so don't feel like you HAVE to do any of this before you can start making stuff. The mods started to arrive as my confidence in machining grew.

Future mod plans (dreams?) include the cross slide DRO, telescoping lead screw covers and a retractable cover for the lathe bed. The latter is based on a scheme that only an electrical engineer-turned-hobby-machinist could think of....more fun than practical, but that's the nature of the hobby.

I don't turn threads often enough to justify ELS, and so far haven't encountered a problem that would be best solved by doing a CNC mod.

 

[Stan the Man]

Wow, sums it up nicely, Lots of improvements made on your end and I am sure you enjoyed doing most if not all of them. It's that personal satisfaction thing. I'm enjoying researching, learning and tinkering with my lathe.

I keep hearing and reading about the tail stock and problems people have. once I get the head stock back together and set aside I will turn my attention to mounting the bed to a more rigid surface. Then address the tail stock.

When my shop was fabricated on site, the frame was built from 2.5 x 2.5 x .078 square tubbing which they gave me a stick that was left over. My thought was to cut up several pieces and weld them side by side then taking some 3/16 flat sheet stock I have and sandwiching the tubing between the sheets to form a rigid base. Then bolt the lathe bed to it shimming and what not to square it up.

I don't know whether or not I would need to fill the tubing with say concrete or epoxy/granite mix. for additional mass. then I could ether keep the lathe mobile (sort of) for now and just clamp it to the work bench when I need to move it. then later dedicate a mobile base with draws, wheels and feet, still mobile but can also plant it rock solid when in use. Your thoughts.

 

[homebrewed]

Wow, sums it up nicely, Lots of improvements made on your end and I am sure you enjoyed doing most if not all of them. It's that personal satisfaction thing. I'm enjoying researching, learning and tinkering with my lathe.

I keep hearing and reading about the tail stock and problems people have. once I get the head stock back together and set aside I will turn my attention to mounting the bed to a more rigid surface. Then address the tail stock.

When my shop was fabricated on site, the frame was built from 2.5 x 2.5 x .078 square tubbing which they gave me a stick that was left over. My thought was to cut up several pieces and weld them side by side then taking some 3/16 flat sheet stock I have and sandwiching the tubing between the sheets to form a rigid base. Then bolt the lathe bed to it shimming and what not to square it up.

I don't know whether or not I would need to fill the tubing with say concrete or epoxy/granite mix. for additional mass. then I could ether keep the lathe mobile (sort of) for now and just clamp it to the work bench when I need to move it. then later dedicate a mobile base with draws, wheels and feet, still mobile but can also plant it rock solid when in use. Your thoughts.

I just have my lathe resting on a home-made wood bench. Not bolted down. I used some scrap plywood from our house-building project for the top. I really haven't noticed a vibration problem when using my lathe. The mill is a different story, I'd sooner upgrade the bench it's sitting on.

But more to the point, I really don't have any insights to offer w/regard to bench design....other than not to repurpose a wood potting bench, even it the top is made with 2x4's . Folks on this site have described lots of bench builds you can draw on for inspiration.

 

[Stan the Man]

Thanks Ill let you know how it goes.

 

[kopcicle]

Bearings , the struggle is real

Atlas 101.21200 Non Restoration

I'm still a little hung up on bearings. I have 7205 w/o seals and frankly don't care for the idea. So the parts keep coming in. The federal test indicator is a welcome addition. The old skool Starrett base is personal preference. I detest mag bases around magnetic swarf. The armature chucks are...

www.hobby-machinist.com