By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Jan 24th

Making split bronze bearings [ silver soldering ]


All Topics | Latest Posts

Search for:  in Thread Title in  
David K21/03/2019 20:52:16
258 forum posts
259 photos

I need to saw a piece of phosphor bronze round bar in half and then solder it back together before machining to size for the split bearings.

My question is, do I put flux on the mating surfaces before clamping together or leave them clean , clamp together and then just run flux along the join.

When the piece is soldered I will need to turn the diameter down so I presume the solder will need to penetrate the join so it stays in one piece.

roy entwistle21/03/2019 21:21:08
1224 forum posts

I wouldn't silver solder. Ordinary soft solder should be OK


Brian H21/03/2019 22:17:35
1746 forum posts
112 photos

I agree with Roy, soft solder is best.


Hopper21/03/2019 22:58:19
4784 forum posts
105 photos

One way is "tin" the two halves with a thin layer of soft solder than clamp the two halves together and heat until solder melts again.

Paul Lousick22/03/2019 04:51:01
1501 forum posts
572 photos

Soft solder is good enough. Thats how I did the split bushes on my engine. Apply flux to all mating surfaces and heat until hot enough to solder. Touch joins with solder and it flowed to all surfaces.

See my post on MEW at click here


Speedy Builder522/03/2019 06:42:27
2081 forum posts
145 photos

If the mating surfaces (After boring) are big enough, superglue can sometimes be sufficient.

JasonB22/03/2019 07:32:57
18659 forum posts
2049 photos
1 articles

I quite often use soft solder paste, apply a little to one face, rub the two together so they are both coated and then heat.

For larger bearings I'll tin (flux heat apply solder and wipe off excess) then put the two tinned surfaces together with some flux and heat again. See this post

vintage engineer22/03/2019 09:13:15
254 forum posts
1 photos

The best way is to use solder paste. Machine both halves flat, coat with solder paste, heat up till it melts then wipe off with a piece of leather. This should leave you with a couple of microns of solder on the bearings Now clamp the two halves together and heat up to fuse the two halves together. If you use too much solder you will have to shim the bearing after cleaning up.

Ian S C22/03/2019 10:31:08
7468 forum posts
230 photos

The way I make con rods with bushed and split big end, bore the hole to take the bronze for the bush, fit the piece of bronze, either a light press fit or Loctite, drill and tap for the big end bolts, now split the bearing and fit the bolts, bore the bearing to size. Usually I drill the bronze before fitting if its been in the lathe to take the OD down to size. Not too practical for main bearings, but one thing is, the bearing can't rotate in the housing, it's oval on the OD.

Ian S C

JA22/03/2019 12:31:32
962 forum posts
52 photos

My attempts at using solder and glues failed so I made a proper fixture to hold the halves. This allowed the ends to be faced in addition to the boring of the bearing.

A little bit of thought and accurate machining is required.

bearing fixture 2.jpg

bearing fixture 1.jpgJA

Andrew Johnston22/03/2019 12:55:12
5635 forum posts
652 photos
Posted by JA on 22/03/2019 12:31:32:

My attempts at using solder and glues failed so I made a proper fixture to hold the halves.

Same for me; the solder joint either gave way when machining, or the bearings required a serious amount of heat to melt the solder - not easy. Depending upon the bearing I made a simple jig:

Crankshaft Bearings

Or made a jig plus the actual bearing housing:

boring crankshaft bearings.jpg


David K22/03/2019 14:05:54
258 forum posts
259 photos

Well thanks for the replies, certainly given me something to think about.

I was worried that the solder on the mating surfaces would compromise the final bearing size

but I see this is not the case.

I will get some solder paste and give that ago first , will let you know how it goes.

Brian Oldford22/03/2019 16:55:09
684 forum posts
18 photos

With any soldering operation cleanliness is next to godliness. Make sure you use sufficient flux to prevent oxidisation of the solder.

roy entwistle23/03/2019 08:33:58
1224 forum posts

David After you've bored the hole and turned the outside don't forget to mark the halves before you split them so that the correct halves go back together and the right way round


Rik Shaw23/03/2019 10:08:19
1355 forum posts
369 photos

For historical accuracy split brasses are a nice touch but I will make mine differently. I shortly need to make 4x PB journals for the crankshaft on my current Double Tangye in progress. They will be made from solid bar, no splits, no soldering! The feed spigot on the oil cups will stop them rotating.

The only splits found on this model are between the CI standards and journal caps. The completed journals will be slid onto the crankshaft then the standard caps will be fitted holding the crankshaft in position.


JasonB23/03/2019 10:19:27
18659 forum posts
2049 photos
1 articles

A lot depends on the layout of the particular engine and crankshaft/pin. With disc cranks and separate pin on the Tangye solid bearings are possible but they won't work if you need one in the middle of a double throw crank or your big end bearing fits between two webs of a solid crank.

What I often do where it is possible to slide the bearings on is to make them as split ones but don't unsolder them, makes it easy when taking the engine apart and reassembling and less chance of mixing things up. The main advantage is if you do get wear or find your fits are a bit slack it you can simply melt them apart at a later date and treat as split ones.

Rik Shaw23/03/2019 11:20:12
1355 forum posts
369 photos

Quite understand what you are saying Jason and I understand that not all crankshafts are equal. However, and as you point out, the DT design does allow for solid journals. My only other engine also had journals from solid. Maybe I'll try another model in the future with the split variety but until then it will remain a "pleasure" to come.



CuP Alloys 124/03/2019 08:41:48
249 forum posts

Hi David.

Paste is an expensive solution to the problem although the technique is sound.

Use a paint. It is cheaper, easier to apply and you will use less of it.

Readily available from any good supplier.



BW24/03/2019 12:24:23
249 forum posts
40 photos

Why do people want to split a bearing and then solder it back together again ? WHat is the improvement that is gained by doing this ?


JasonB24/03/2019 13:14:43
18659 forum posts
2049 photos
1 articles

You don't actually make it and solder back together. You solder two pieces of bronze together and then ream or bore the hole before melting them apart. two main reasons:

1. A split bearing can be tightened to take up wear.

2. On a typical one piece crankshaft you would never be able to fit the big end bearings if the bearing was solid with a hole in it. No other way to get something like this

To fit around the middle of this

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Eccentric July 5 2018
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest