As for a book reference, there's always this:
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| How to Pour New Journal Bearings https://www.rypn.org/forums/viewtopic.php?f=1&t=37776 |
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| Author: | softwerkslex [ Tue Mar 03, 2015 5:41 am ] |
| Post subject: | How to Pour New Journal Bearings |
Would someone provide instructions or a link to instructions for pouring and fitting new journal bearings? I am also interested in rod bearings, but would the steps be the same? Thanks. |
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| Author: | Dave [ Tue Mar 03, 2015 9:45 am ] |
| Post subject: | Re: How to Pour New Journal Bearings |
If I understand you what you want is to reline a brass with babbit? First, build a mandrel that the brass clamps on to and will act as a mold for the lining. It wants to be a bit smaller in the axle diameter than the desired size to allow for machining if you plan to machine the fit - if you plan for it to wear in, try for a match in size to the axle. Next, clean the old metal off the brass shell. Use soot from an oxygen deprived acetylene torch to coat the mandrel so the new metal won't stick to it. Clamp the clean bearing shell to the sooted mandrel and do a bit of judicious preheating of the brass - just something like you'd get in your oven baking a ham. Melt the new metal and pour it in until it is full, it will of course get a bit smaller as it cools. When cool, separate the brass from the mandrel and, if you did it right, the lining will be on the brass and not on the mandrel. Now, you can machine, scrape, or otherwise do a bit of final fitting of the brass to the axle and to put in whatever grease or oil passages you desire. If you plan to run it in, try a dose of Time Saver lapping compound at first to speed the wear in process - it laps then turns into an innocuous substance that is no longer gritty and abrasive. Rod brasses are something similar, but with the caveat that you will want to machine the final ID and make sure you do not alter the length between centers on the rod in the case of unadjustable sleeve brasses. Split rod brasses are like small axle boxes in the way you line them. There are good books about blacksmithing and machining that can go into greater detail, but this is the basic process. Your mileage may vary. Good luck - and don't overthink it. dave |
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| Author: | softwerkslex [ Tue Mar 03, 2015 12:39 pm ] |
| Post subject: | Re: How to Pour New Journal Bearings |
Yup. Recommend some of those books? What is the trade off in machining to fit versus wear in? I imagine labor time is a factor. |
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| Author: | Dave [ Tue Mar 03, 2015 3:30 pm ] |
| Post subject: | Re: How to Pour New Journal Bearings |
Machined bearings generally start cool and stay that way until something goes wrong. Run-in bearings only fit loosely until they seat on the axle, so for a time the size of the bearing surface is not as large as the final finished surface, so it can run a bit warmer for a while. On the other hand, both actually run in to a final fit, so......if you have good machines and good machinists, there's no loss to putting them to use. If not, just plan on a couple break in runs with light load. Home machinist and blacksmithing web sites have a lot of links to reprints of old books and new books also - I can't recommend anything in particular, since all I have are old books found in a lot of laces over the past 3.5 decades or so. I think there is one publisher that specializes in this kind of thing, don;t know the name offhand, but he has small foundry books and such as well out there. I'm sure you will find it if you search a little. dave |
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| Author: | hamster [ Tue Mar 03, 2015 3:40 pm ] |
| Post subject: | Re: How to Pour New Journal Bearings |
There are some really good videos on YouTube that show all the steps to pour babbitt bearings. Here's one about the steps and the actual pour. https://www.youtube.com/watch?v=wZh2VZbqQiI And this series, starting with: https://www.youtube.com/watch?v=LKmwi2QR3Ug is about the repair of a large very old chop saw including enclosed babbitted bearings. Very similar to what you want to do. |
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| Author: | fairmontdave [ Tue Mar 03, 2015 3:50 pm ] |
| Post subject: | Re: How to Pour New Journal Bearings |
Lindsay Publications was the Company that reprinted old technical books, but Lindsay retired in 2104. They do show up on eBay quite frequently and are usually inexpensive (under $10 or so). A lot of the older books can be found at you local steam show/threshermen's reunion, or at the Cabin Fever Expo in York, PA in April. When I was in the cement business, we used to pour bearings for the cement grinding mills that were over 3 feet across and consumed 250 or so pounds of Babbitt each. The melting was done in a crucible with a rotating arm over a coke furnace with a blower to get a higher temperature. I think we used Stonewall Babbitt...has a picture of an Indian on each ingot. The former comment is correct, just make a mold of what geometry you want, make sure it is sealed up with no cracks and pour the molten Babbitt in gently. I think it melted about 275 degrees, each Babbitt will melt differently depending on the composition of that particular alloy. I remember that the crew used to wind a piece of manila rope about 1/4 or 3/8 inch diameter around the mandrel in a "X" pattern to create a grease passage/groove. |
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| Author: | Howard P. [ Tue Mar 03, 2015 7:02 pm ] |
| Post subject: | Re: How to Pour New Journal Bearings |
While we're on the subject, I've always wondered how the babitted bearing surface on AAR-ARA plain bearing brasses is machined. One does not see tool marks in the soft metal surface-- how is that done? I recall seeing old ads for something called a "journal brass reconditioner" machine, portable and designed for use at RIP tracks. Some sort of shaped tool and a broaching-type movement of same? Howard P. |
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| Author: | Dave [ Tue Mar 03, 2015 9:22 pm ] |
| Post subject: | Re: How to Pour New Journal Bearings |
You wouldn't want to broach across the bearing surface, but in the direction of the turning of the axle - as you would in a lathe, or a mill, so there is no chance of a transverse problem with the bearing interrupting the oil flow across the surface of the journal. Many were not machined, and more scraped in after machining, although I personally think that's overkill for railroad tolerant technology. dave |
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| Author: | Howard P. [ Tue Mar 03, 2015 11:07 pm ] |
| Post subject: | Re: How to Pour New Journal Bearings |
I've used a scraper and scraped in/fitted in plenty of brasses for plain bearing cars, but I was wondering about how the babbitt surface is made so smooth, hard to think it's machined after pouring. Howard P. |
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| Author: | mjanssen [ Wed Mar 04, 2015 12:16 am ] |
| Post subject: | Re: How to Pour New Journal Bearings |
It is more common to see bearings centrifugally cast and precision machined in industry today as engineers and mechanical people expect very high contact areas and aesthetics. Like a contemporary automotive bearing, these do not need to be scraped or bedded-in. Typically, however, most legacy designs allow for the less than perfect contact areas that come with traditional techniques. If you are pouring or reworking an adjustable journal bearing, or a bearing half, Timesaver can be used. http://www.ws2coating.com/timesaverlappingcompounds.aspx |
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| Author: | stephenpiwowarski [ Wed Mar 04, 2015 12:40 am ] |
| Post subject: | Re: How to Pour New Journal Bearings |
Dave, I think the book you may be thinking of is "How I Pour Babbit Bearings" by Vince Gingery. It's still available on Amazon. Steve |
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| Author: | Dave [ Wed Mar 04, 2015 12:57 am ] |
| Post subject: | Re: How to Pour New Journal Bearings |
Thanks Steven....I don't think I've heard of that one but based on the title it should be pretty applicable. dave |
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| Author: | S. Weaver [ Wed Mar 04, 2015 11:41 am ] |
| Post subject: | Re: How to Pour New Journal Bearings |
After backer spec and prep, we do a rough pour and then custom fly-cut the babbitt for the journal. This may seem like a little overkill, but our bearings just have to work from the moment of installation. Rule of thumb oil clearance for us is 0.015" Your mileage may vary ... |
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| Author: | wilkinsd [ Wed Mar 04, 2015 1:46 pm ] | ||
| Post subject: | Re: How to Pour New Journal Bearings | ||
As for a book reference, there's always this:
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| Author: | softwerkslex [ Wed Mar 04, 2015 2:45 pm ] |
| Post subject: | Re: How to Pour New Journal Bearings |
I am too young to get that joke |
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