Cast Iron Pulley Repair: Brazing in a Broken Chunk, Turning True on the Lathe

Cast Iron Pulley Repair: Brazing in a Broken Chunk, Turning True on the Lathe
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[@masteruniverse3506]

It always amazes me how a "simple" job can require so much work to get it correct. Thanks!

[@dan-o9746]

That turned out great! I am amazed that when you took the clamp off the small piece to do the inside face, it remained in place when you got it up to brazing temperature. I figured it would push out of position when you added bronze or fall off when it glowed red. That bronze must be pretty stable at high temps. You're a master at it. Very skilled repair!

[@clydecessna737]

Good to see you looking much, much better.

[@paulputnam2305]

Fantastically Awesome Job

[@wallbawden5511]

Another nice repair nothing short of your best on all your work Cheers

[@jacquespoirier9071]

doing something is one thing, doing it right is another ball game excellent job on that repair very good video

[@componenx]

I have yet to come across a broken pulley sheave in cast iron. In my case, it's always zamak or some other non-repairable alloy. I did try brazing a zamak piece from an Atlas shaper once; got about half way done, added just a tad too much heat, and the entire section sagged. Love these repairs!

[@michaelkoch2109]

Thanks for showing! Best regards from Dresden!

[@mudnducs]

I love watching your brazing repairs

[@melshea2519]

Happy Friday Keith! Thanks for the awesome videos! 😊

[@jodyvanliew2514]

Very nice job as always Keith .

[@busman2000]

Merry Christmas Keith and I hope you have a Good New Year filled with good fortune , good health and happines for you and all those you love and care for.

[@RRINTHESHOP]

Great repair Keith, nicely done. Merry Christmas.

[@walterplummer3808]

Good morning Keith. Thanks for the videos and Merry Christmas.

[@joeromanak8797]

This proves once again that setup time often exceeds actual machining time. This was a well executed repair, as always. I liked it. 🥸👍👀✅

[@edsmachine93]

Very nice job Keith. From the brazing to the machining. I really like how you had taken the time to make a arbor. Definitely added a level of precision to the project. I noticed the pully had been precision balanced. As a person that does balancing, I am certain that the pully is very close to the original balance. Nice video work also. I liked the view over the top of the pully groove machining. Thanks for sharing the process. Have a great weekend everyone.

[@pilgrimm23]

thanks Kieth. You are in many ways....a master...

[@JonDingle]

Great work young man!

[@MrChevelle83]

kieth is around 60 yrs old

[@michaelsimpson9779]

Nice work Keith

[@peltona]

Great repair!

[@royd.mercer1727]

How fortuitous! You've never mentioned your talen of clairvoyance in the shop... because I needed to see this. Thanks for all y'all do!

[@pilgrimm23]

he has done that to me too.

[@gordonmcmillan4709]

Interesting to see balance holes drilled in the back face of the pulley when you turned it over.

[@MrChevelle83]

cast iron high speed pulleys are usually balanced. steel are much lighter and not always balanced. but sometimes are in critical situations.

[@JoTa8389-gu9vi]

I wonder if the repair took it out of balance a little

[@garys9694]

Sure did@@JoTa8389-gu9vi

[@PhilG999]

@@JoTa8389-gu9vi Probably, but given the relatively slow speeds involved it might be measurable but not noticeable...

[@elsdp-4560]

Thank you for sharing.👍

[@bulletproofpepper2]

Thanks for sharing.

[@johncloar1692]

Nice job it look like it turn out well good job on showing how to turn a angel on a lathe. Thanks for the video Keith.

[@scrotiemcboogerballs1981]

Great video thanks for sharing

[@jtg2737]

Damn, that came out better than what I had anticipated!

[@6NBERLS]

Most excellent.

[@robertlewis2]

Keith, you are a wizard with brazing repairs!

[@davehiggins5903]

Nice repair

[@tomswindler64]

Impressive job 👍👍👍😎😎😎

[@user3141592635]

Great job. I would however personally have coated the broken surfaces with silver-solder apart, or in two. Then apply flux, hold them togheter under heat and spring-pressure. Spring pressure so as to press them toghether with no disturbances. No machining, maybe some little, little filing. The gap of Silver-Solder, would just be a hair thin, and an extremely beatiful repair. This method is sometimes used in Gun-Smithing for broken parts. Just a little thin line of a darker colour of silver and copper, 0,05 mm thick. The more silver, the better, but I think 44% is good enough, and with a good brazing flux of cource. You do not have to prepair the broken surfaces, other than de-grease them. It is plenty strong, I have professionally performed burst-tests on details made out of copper, and this brazing-solder is way, way stronger than copper. Very strong and very ductile as well. Well in par with cast Iron or way, way better.

[@moosesmachinery]

In an application like this where the part is deformed, that may not be the best option. I do a bit of both in my shop, and silver soldering works best when you can easily fixture the part and hold it in place. I use a silver solder paste that is self fluxing. Apply to the parts, heat till it flows and clean up. It's pretty straight forward and easily done.

[@user3141592635]

@@moosesmachinery Silver-Solder paste is King, as well as soft-solder paste, but it is cheaper, to use a rod and separate flux. Just drop the heated rod into the moist flux now and then and apply it into the heat. It is the same as useing prepped silver-solder rods.

[@user3141592635]

@@moosesmachinery I suppose broken cast-iron peices are not generally deformed, but suites quite beatifully together.

[@SmartCNCs]

Great

[@geraldharkness8830]

fantastic work keith saved another piece!

[@flinch622]

You stumbled into a great question: what IS the proper angle? I tried a quick serach and...half the crap burped up was on pulley alignment. We've been using belts for so long, we barely ever think about it. It seems to me its actually... a variable, and that because the narrow section of the belt deforms differently depending on the radius of tha sheave. It seems anything between 32 and 38 degrees can work. Main thing is the high friction load area of the belt stays near the outer band - maybe 1/3 or nearabouts? Anyway, only the belt has 40 degrees [unstressed] and that for sure is wrong on a pulley. I was guessing 32 until your lathe proved 30 - that is a tight radius.

[@Andrew-so3vj]

Great video, Keith. But what is happening with the stoker engine? I really enjoyed watching you dismantle and prep that, but sure would love to see it progressed.

[@mathewmolk2089]

Anybody that knows me knows i get all up tight when anybody even suggests repairing cast iron with anything but cast iron gas welding. ,,,,,, Not there is anything wrong with brazing, but i make verbally un-delectable repairs with real cast iron filler. BUT-----lately over the past several months I have been experimenting heli-brazing with Phospher bronze, silicon bronze and aluminum bronze for things like broken gear teeth and motor brackets and I put a steel replacement end on the oil soaked chewed up cast iron horizontal band saw vise here. It seems to be working fine. Phospher bronze seemed to self flux all the crap out of the iron, ,,,,, I still fully pre and post heat in the furnace but it sure speeds things up and I am not getting burned and hurt as much as with the real thing. - You can see the repair from across the street. (never get away with it on antique restorations) but it is sure a lot easier then real cast iron . Kieth, you are converting me. ,,,,, Or is that corrupting me. ????? looking at that squeaky clean break in the pulley what do you think about silver soldering it? - Might even get away with a flap wheel on a die grinder to finish it. - OK....Too many beers after supper. (Got to cut out that Black Velvet too.....Just another bright idea from Cleveland

[@jrmintz1]

Fascinating! Sometimes you cut a thread relief at the end of a threaded section and sometimes you don't - when and why is it called for and when is it not? Thank you. BTW, you are looking positively slim! Congratulations, it's quite an achievement.

[@MrChevelle83]

its not that a relief is 'called for'. it depends on the type of thread and situation. when turning up near a large shoulder. a flick of the dial wont get the tool away from crashing. so a relief is need to just unlock the half nut which is easier to do in a snap reflex. in this particular case. the rod was the same diameter as the threads. so he. can unlock or disengage the half nut and roll the dial back to get the tool away from the bar without hogging into it with a full depth thread cut. he knows this lathe really well and has been cutting threads for over 30 years.

[@jrmintz1]

I see. Thank you very much.@@MrChevelle83

[@kennethstaszak9990]

Sometimes it depends on the application. Unless the relief is a radius it will create a stress riser. Some applications are under enough stress a relief could cause breakage.

[@TradeWorks_Construction]

I fully agree that braising is by far the best choice for cast iron repair. I’m not saying that welding is bad as there are many scenarios where welding would be just as effective. In general welding requires far less time but it requires a different touch than flame braising. I’ve done a lot of successful repairs on cast iron pulleys and I love the pre-fluxed rods. There is no easy way to teach it, you just have to experience it and experiment but the 2 universal things to give the greatest chance is good prep(grinding, fixturing, preheat) and SLOW gradual cool down. Personally I prefer burying my parts in clean white sand but a good large fiberglass blanket works and is cleaner. I’m sure this will always be a debated topic but I can confidently say: You hear all the time about a cast iron weld failing but you don’t hear anyone complaining about a solid braise.

[@mathewmolk2089]

If when you talk about "welding" cast iron, as in electric welding, I couldn't agree more, and there is nothing really wrong with gas brazing or non ferrous TIG, but there is only one way to PROPERLY repair cast iron and that is gas welding with real cast iron rod. - We have a reputation for antique cast iron furniture and very old machinery restorations and gas welding is the only way to make it look like it never happened. - It aint easy, and it aint cheap, but anything else aint right. ,,,, especially on 200 year old parts that are not getting painted.

[@stevecallachor]

I’ve eaten braised beef and onions but I’ve never eaten braised cast iron………Iron I’d probably more serviceable when brazed. Stavros

[@samueltaylor4989]

3 jaw puller strikes again!

[@johnpietros9439]

I’ve never ever seen it done any other way

[@maureenmillard4241]

I cheated and used JB weld still going strong!! Mal.

[@jimwinchester339]

Would have liked to see you fashion the tiny-button carbide tool.

[@currentbatches6205]

1:38 - Ever silver-solder CI? It wicks into seams really well, but never tried it on CI. 2:49 - That ring-finger nail had to hurt when it happened. 20:18 - Masking tape is real close to .005". Put some in there, you'll be able to tell when you are close to .005" of the larger or smaller dim.

[@chrisstott2775]

Why the need for the key on the arbor? I would thought that the pressure of the nut and spacer would sufficient to hold the pulley. We are not looking at heavy cuts and the cuts are near the centre of the pulley so not as much torque to consider. More curious than anything, is there something i am missing or not thought of.

[@Craneman4100w]

Could have indicated the angles too. Faster and more accurate than fiddling around to figure it out but that's our Keith.

[@butter262]

That finger nail is looking better.

[@paulmorrow5905]

question. would machining the front edge off completely. then pressing on a new front edge. then machining the profile back have been a another way to complete that task.

[@sjmazzoli]

👍

[@stevecallachor]

Break on the outside sheave tells you that someone used a bearing puller. Tch, Tch,!!!! No, no no!!! But………you could say it broke when it fell on the concrete floor after it fell off by itself. Fear not, I have done this more than once , so that’s how I know what happened. Stavros

[@garybrenner6236]

When will you start on the Stoker Engine?

[@AnvilDragon]

SAE V-belt 36 degree +/- 0.5 A bit suprised you would look on the internet for that.

[@TheJbh1103]

does the the length of the workpiece affect accuarcy

[@truracer20]

It would save on gases if you use your heat treat oven to preheat items that fit.

[@JFirn86Q]

What lens/glasses do you use to be able to see through all that huge yellow flare?

[@RambozoClown]

Looks like time for some new shirts.

[@Histandard2011]

Don't you have tons of expandable arbors you could have used?

[@jmptaz]

Keith, The lathe sounds a little rough are the bearings wearing out lol

[@jimforsyth2.]

Could this be sliver soldered

[@tomnorton8218]

As reply newbie I have a question. Why couldn't this pulley be chucked up in a 4 jaw and turned?

[@claygormish4884]

Needs to be true to the center line. Easier to make Arbor than align the center line of the bore in the four jaw.

[@MrChevelle83]

it could with no issue. but the arbor is faster and id use it too if i was machining this. but if all you have is the 4 jaw it would just need to be indicated in really well.

[@tedmiles2110]

Another of your first rate repairs! Sorry that you smashed your finger nail. Outch! TM long time viewer

[@wallaceknifeworkshomestead]

Good job! You look tired today.

[@lexpee]

It is nice job but why brazing and nog superglue. Years ago I had the same thing with a pulley. I glued the broken piece with superglue and it is still stuck. Why make it difficult when it can be easy.

[@ellieprice363]

Super glue would not make a good educational video.

[@MrChevelle83]

why dont you make a video on that and be the first machinist in the world to repair a high speed castiron pulley with super glue. then install it on the machine it goes on and put it to work so then we never have to braze one and machine it ever again????

[@lexpee]

I glued the broken piece with superglue and it is still stuck after 10 years. The drive pulley is mounted on the diesel engine to the alternator 230v 50hz 5000 watts. These types of broken pieces can easily be glued. ​

[@mikewatson4644]

I believe that he said the broken piece was deformed, probably when it was broken. Just glueing it in place wouldn't correct the deformation.

[@oldschool1993]

Just grip the pulley in the chuck.

[@rival9417]

Why didnt you just leave the arbor 5mm short and use a tailstock attachment to pressure hold the part? Much easier

[@davehulme3106]

Keith’s got plenty of time.When you have a customer waiting in reception you don’t have the time to make an arbor.

[@rossnolan2883]

😊😊😊😊😊😊😊

[@dangodbout7818]

That looks like a pulley on a belt driving knee mill

[@headgrinder-t7s]

If you worked for me I would fire you. You never take your hand off of the chuck key when it is in the chuck.

[@cornnatron3030]

as you mentioned that this would be a perfect piece for tig brazing would it not also have been a perfect piece to get more familiar and proficient with tig brazing

[@samuraidriver4x4]

On the inside it would have been a bit more tricky. Pretty tight space and alot of stick out needed inside of the groove. Oxy/acetylene is a bit easier.

[@cornnatron3030]

@@samuraidriver4x4 i get totally that its easier but if you dont try and practice it never gets any easier neither

[@mikewilson631]

I would have made a paste with flux and brass or spelter filings. Paste it onto the broken faces, cleaning off excess, and then clamp them together. Heat with a propane torch until you see the braze run all through the joint. I think you would have had fewer gaps (if any) and much less finishing work. Maybe just some hand filing and cleaning.

[@Digital-Dan]

SHould be said that the TIG brazing would have been much more instructive; I for one have never seen it done.

[@mathewmolk2089]

Just like gas - only get the part up to temp and try to keep the arc mostly on the rod and avoid melting the base metal. - There are a few vids on it.

[@charlesmiles9115]

😛😛😛😛😛😛❤❤❤❤❤👍👍👍👍👍👍👍👍👍

[@billywird]

🥸👍

[@jacilynns6330]

Something I will never understand is why people v out for brazing which makes the weld weaker. Brazing strength is strongest when it flows into the crack or lap weld.

[@robmacl7]

I don't know why the "braze welding" you do on cast iron is different, but it is. Big difference is that you don't heat to the temperature where the filler is fully liquid. I'm sure a big issue is how brittle cast iron is. There are usually missing parts that you fill in with braze. The vee may help to reduce stress concentrations in the repaired part by giving more brass between the parts act as a buffer. One possible problem is that the tensile strength of the braze is higher than that of the casting, so it can peel off. Veeing out gives a smooth surface on the cast, maybe less likely to re-fracture at the interface.

[@robmacl7]

Another thing about cast iron is that it has a lot of graphite in it, which is weak. If you look at a broken surface it is going to have more graphite exposed, which I think doesn't bond well to the filler. Anyway, the usual repair method gets rid of all the broken surface, so it seems that the broken surface is a problem.

[@ellieprice363]

When broken parts are clamped up tight with the edges perfectly matched the braze material cannot get into the joint. That’s why broken edges are always V’d out. Makes perfect sense to me.

[@millwrightrick1]

@@ellieprice363 Brazing is like soldering in that capillary action makes the metal flow into the joint. When the iron is hot enough the brazing will flow.

[@arazusaysbah6784]

@@millwrightrick1 No it won't. The hairline crack in broken cast iron is too small for the bronze to flow into.

[@carllatta871]

I love how you call everything cast iron when you know it's cast steel.

[@wesleymonske8103]

Holy moly , owie. There are easier way to know your left from your right.Ha Ha yeow! Be careful and wear gloves. Too late I know but be careful.

[@billmckillip1561]

👍

[@toms6213]

👍