Gear Dentistry: Repairing a Broken Gear Tooth
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- Опубліковано 21 жов 2024
- A viewer asked if I could help him by repairing a broken tooth on a back gear off of his South Bend lathe. Instead of brazing it up and cutting a new tooth, I decided to go at things a different route. This time, I milled the old tooth off and cut a pocket underneath it. I then machined some cast iron to have a piece that I could silver solder into the pocket to form a new gear tooth. The part was machined on the lathe first to get everything round again and then a new tooth was formed on the horizontal milling machine using an involute cutter and dividing head.
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Lesson learned. Looks like I will no longer use my backgear to remove my chucks... Thanks, another nice video Keith!
Whatever makes you think we don't like to hear you talk Keith?!! Its it your friendly and approachable style that makes your channel so enjoyable and so much fun to watch. Don't change a thing!!!
Keith - This project used several tools and machines. That is what I enjoy the most - lots of tools. Someday I would like to see a project where you use every tool and machine in the shop!!!!
Thanks for the comments on cheater bars/pipes. I was told long ago that a cheater pipe is a special tool used to bread the head off a wrench. Now I know a different way to use a cheater.
Something that I have really respected about you Kieth is that you take adequate time to both explain and “show” your work. This video, at least at the beginning seemed uncharacteristically rushed. You then make a comment that people don’t like to hear you talk, and I think that you are wrong. I like your explanations, and that you are thorough, yet you keep the video moving and hold the interest of your viewers. I have been critical of some of your videos in the past, but I remain an avid viewer because you are authentic. As I see you making subtle format changes, I ask that you please don’t stray from what has made you so well respected within the UA-cam creator world. Regards.
That looks like the best tooth on the gear now, Keith, well done.
Hi Keith,
I know you have said that this is a very busy time for you, so I appreciate your time and effort to produce and publish another video for us.
Thanks very much for all you do for your viewers on your channel.
Another nice learning what things do before he shares how to fix it, for these two this is really important in understanding what likely caused the break in the first place, what is needed to sustain a life after repair then repair it with that knowledge. This is why we watch Keith's videos other then we like him for being a nice and helpful man. It is funny must share when you do not own a surface grinder lake many tools you so want one, we want and must earn one someday. A great fix of that gear tooth. Great dividing head what a nice tough head. Lance & Patrick.
You did a great job Keith. You always do. I have finally begun using the old model 9C Southbend lathe I bought years ago and restored as best I could. It previous owner(s) did not take care of it and it has some missing teeth on the back gears. I repaired large gears years ago when I was a machinist and we'd drill and tap a line of holes, screw in bolts, cut off the head, then with a template made from the good teeth use that to hand grind/ file the profile of the "new" teeth.
Top notch work again Mr Rucker.
Always nice to see repairs to the older machines them just replace something and throw away history
That flux is GOOD stuff. I use the same in the missile parts I assemble. I use a silver braze material made by Hastings. All of our joints have to be flow tested as well as pressure tested for leaks then x-rayed for any voids. Mil standards require an almost perfect joint. Some are very small and have to be done under a microscope. We also do a lot of induction brazing. Good repair. Should last a long time.
Nicely done Keith!
Thanks for showing us another perfectly good way to carry out a tooth repair.
Keith, they make 56% & 45% silver solder in stick form, unfluxed. In case you were ever wondering. I use it going copper to steel in the HVAC industry. The pre-fluxed blue & orange rod are a mess.
Great work as usual Keith!
Great intelligent and effective repair Mr Rucker.
Thanks for sharing and best regards from the UK.
Missed that horizontal mill! Like the talk. You walk the walk.
Nicely done Keith, silver solder is the way to go on that job
Thank you Keith!
Keep talkin Keith, thats why I watch your videos. I want to learn not be entertained.
The amount of yak-yak versus hack-hack is about right to my mind.
People can skip forward if the talk is boring them. The rest of us like to be better informed/educated.
Why not both?
Great job!!!!! See you at the Summer Bash.
Great topic, Keith!
19:29 looked a little healthy for a clean up Keith! Than that blasted nick in that neighboring tooth, but it is better than it was when missing a tooth though! Not every job comes out perfect. I have a chip pan that is a testament to that! lol
A most useful video as I have a 9" South Bend lathe that is missong a tooth on each end.
Hi, I used to silver solder carbide to tool holders instead of constantly buying new. Anyway, I used sheet solder so the part settled fairly uniform. You can watch it flow. When I didn’t have the sheet or flat ribbon, I would just hammer the round stock flat. Just a little old time wisdom! ; D
Good video though! I enjoyed the gear shaping.
excellent video discussion/demonstration/build
Repairing tools is very satisfying.
Why did you not show a closeup of the repaired tooth?
Good stuff Keith now can you make another 100 of them LOL.
i have learned a lot by watching keith
G’day Keith, interesting choice of material I would not have thought silver solder was that strong, well done.
Cheers
Peter
Great repair Keith, should last as long or longer than the original teeth.
What a great way to repair that tooth! Again Dunkin Donuts coffee and an outstanding video from Keith! Boy life is good!
Thanks Keith!! 👍👍👍👍👍
I liked this repiar, different and well thought out.
Thx Keith
GREAT job on the implant. Thank you, thank you, thank you for the warning on removing an SB chuck. I have used the back gear in the past but not anymore. I found a piece of 7/8" hex material to put in the 3-jaw and will first try my impact wrench. If that does not work, then I will use a strap wrench around the cone pulley.
When adding braze/silver solder in a tight spot I've had some success hammering the end of the rod flat before using it. Ever tried that?
Good repair
Intetesting Repair video Keith. I recently visited the Hagley Museum in Delware. They have a water powered line shaft machine shop. One of the tasks of the shop historically was to maintain the mill machinery. There are several examples of gear teeth repair. I'm not sure if they brazed them in just as you have, but the teeth were fitted in and screws machined in from the end.
I LOVE IT!! proof that Rucker IS human! he missed his edit at 2:54 - Thanks for leaving that in! I LOL'd hard! best video yet!
Keith, I would have enjoyed seeing a closeup of the new tooth at the end, perhaps from a couple of angles. Great video!
Explain away. Its nice to know why it works.
Smart solution.
That is not a crown, that is an implant... Nice work! Thumbs Up!
Great job Keith 👍
Nice repair method!
That is a great repair, a bit more trouble than brazing it up
Outstanding repair.
Love to hear the how/why you do things.👍
Great vid... would love to see macro close up fotos as well...just to see the join between the two surfaces.... and silver solder...
Love your vids , make it look easy...!
Nice video - but did it actually work? I did few gear repairs most through brazing and none actually last a long time. Once a gear goes brazing stuff on and cutting new teeth is temporary fix. With steel gears I found tig welding and cutting it out works. Not sure whatever high nickel cast welding and cutting it would work well - maybe something to try?
Would have been good to see a close up shot of the repair? Looked like the tooth next to the repair was damaged as well, but since there was no close up we'll never know. That being said, it appeared to be a well thought out solution for fixing that gear.
Yeah I thought that too.
Is heat treatment an issue on cast iron? You got the gear red hot, is this a concern regarding it's strength?
thank you doctor.....this new silver is looken good
bling bling
This is a unique solution. I like it.
now i know why its so expensive $$ and worth it .machine/ tools, knowledge, time
Thanks for the video.
I agree keep explaining a person tends to learn more..
Love this repair strategy. Definitely stronger, cuz physics! Just an fyi, I noticed quite a bit of breathing noise in the audio. Not sure if you wanted that. Thanks for the great entertainment and knowledge!
I have shown concern for Keith's respiratory health in the past. He never got back to me.
@@jonka1 I was just pointing it out for quality reasons, his health is his own business.
HI KEITH ! I LIKE THE FILL AND CUT TOOTH. NEW WAY HAS TOO MANY OPERATIONSCARL
Great repair job looks good!
Watching in Alabama!
Nice job !
Our 15" Cincinnati lathe is currently down because of similar issues. We have a few gears on the way and since it's down we're repairing the cross slide play issue.
Keith, you're such a warm, affable guy that I don't like critiquing your work, especially when you got such great result on this project. But the most interesting part was the final tooth milling and for over half the film time, we were 6 feet away looking over your shoulder. Put us closer! Make us get our safety glasses on to avoid the flying swarf.
@25:08 onwards check out the damage to the adjacent tooth, also the burned off corners of two original teeth (perfect @11:10) This may be why we don't get any close shots. The truth denied is still the truth. I wonder what the trusting owner will say.
chris0tube
Hmmm Yes I sometimes wonder why I watch this man. My best excuse is that he often works on interesting items.
I did invite replies about the loose centre but yours is the only other observation and yes about the careless removal from the OD of the teeth.
Regards from Wales
Keith: Never too much talking; your explanations are very helpful in understanding the details of the repair process. Thanks!
THANK YOU...for sharing. Fantastic repair.
They use silver solder to attach carbide saw tooths in woodworking saw blades, and if I recall correctly it is used to solder carbide inserts to boring bars and such in metalwork world. Amazing stuff. And Keith, abom79 got some tooling from auction, hit him about some taps and such you might need since he is going to get rid of most of it.
Pro, thats great work their.
Great job, but not at everyone's reach! How much would you charge someone to do this and how much would a new cog (if it can be found) cost?
Yep, good work.
Good One.... Nice Idea....!
Congratulations.
Very nice job.
Nilton Polydoro
A1 repair. 👍👍
I'm curious, would milling in a dovetail joint for the tooth to slot into, mechanically trapping it in the shaft, been any stronger/secure or would that have presented any negatives or risks that would have made it not a desireable solution. Or would it have just been overkill?
An interesting way to repair a gear tooth. There are always more than one way to do anything.
Would you say it was quicker than brazing the new tooth on, which is the normal repair process?
Was it hard to reindex cutter to the gear tooth? I didnt see that part in video. Is that easy just align it inside good tooth?
How much would it cost to fix a few teeth on a bull gear for my clausing that I just bought?! I think it has 4 or 5 missing (I know a lot). But I have no idea where I can find a replacememt
Always enjoy your videos. Can’t thank you enough.
I have a request for you help repairing a Albrecht chuck part. (The spindle) I think it would make a great machining video.
Thanks!
Nicely done.
Thanks.
Great video. Love your work shop. Love your machines. I have a question. When you heat up the gear doesn't it soften it? Don't you have to re harden the gear? Thanks
So, did you charge at machinist rates or at dental rates?
Thanks for the video and process Keith. I have a SB 9 inch and the back gear was repaired by brazing in the past, prior to my getting it and you can tell by the clackety clack racket they may have used the wrong cutter. Do you happen to remember which cutter you ordered? DP? All that. I have some cutters but I am not sure they are correct. Thanks and I hope you and yours are all well.
Norm in Arizona
You might have a better chance of getting in touch with him if you email him. I haven't seen any replies from him in the comments section in a long while. Not saying that he doesn't or won't, but when I used to see him comment after first posting his videos....I just don't see it anymore.
Machinery Hand Book has the spec.
I have same problem with my sb9. Have same question as well!
High silver content solder has tensile strength of about 70,000 lbs while bronze is more like 30,000 depending on the tin content. Both repair methods are good and should be “as strong as” the cast iron
Nice to see someone actually repairing something for a change instead of just replacing.
Btw, what did you charge for that work?
Hum, that extra solder on the top of the teeth looked cold. Normally silver solder flows like water when you get it and the metal up to temperature and flashes around the joint by capillary action. You normally won't see a pile of silver solder like you seel piles of braze metal. The biggest blob you are likely to see is a drip of solder.
No, it wasn't cold, it changes colour, and I can assure you, it was correct.
I know, I've done loads of silver soldering!
The "extra " solder was just that. It had no bearing on the attachment of the tooth. The solder joint was solid where it counts. Nice repair. Silver solder is an extremely strong repair of cast iron. I would guess the added cost keeps it from being a common choice for cast iron repair, but there is no better way and all repairmen should have it in the toolbox.
Can you suggest a better way of removing the Chuck from out little lathes?
Keith, very nice repair. Can hardly see the new tooth. Should the threads on the chuck be kept lubed to prevent sticking?
Can never find what you need when you need it, when you no longer need it, that is all you will find. Lately it seems that everyone I've watched cut gears has had to order the cutter in. I'm beginning to think that shaper cutting gears with that rotation setup that JB From Oz demonstrated wouldn't be quite so tedious after all.
Love your channel. I can't help but wonder what changes in my life might have taken place if UA-cam had been around when I was a kid. I have a question. Since I see you generating a good deal of scrap metal, I'm wondering if you recycle it and if so, how? Thanks
Awesome, How much for back gear and mating bull gear teeth Repair on an old southbend!?
What happened to the clip of milling out the pocket?
It stopped a bit suddenly.
It's a smart tooth.
I suppose everything depends on how you look at it. "Silver soldering is brazing with silver alloy." Or perhaps brazing is soldering with brass. ;-)
Silver soldering and brazing are technically called "hard soldering". Hard soldering is the mechanical connecting of two pieces of material without a fusion connection and using an alloy that melts above 800 *F. below this temp it is called soft soldering.
The term brazing is an archaic term and really only applies to those repairs done with brass. In other words the word brazing is a description of the alloy used rather a statement of process.
Why is that soldered and not welded?!
A+ WORK
Cool!
I see a similar comment below, and will ask a different way. Is using the back gear the prescribed method for locking the spindle when trying to remove a screwed on chuck? I thought it was, but there is probably a way to avoid harming the back gear.
No! I like using a belt type strap wrench around the top cone pulley with even pressure blocking the handle and turning off the Chuck with an adjustable wrench on one of the jaws or if it is really stuck put a piece of stock clamped in the jaws and put the wrench on it You still have to be careful that you also don't break the locking block for the cone pulley when things are extremely tight. When reinstalling, clean threads and mating ends, very lightly oil and DON'T snap the Chuck on.
@@edwardkawecki8101 I very much notice you do not include smearing the threads with Never Seize. The copper coloured high temp version is grainy enough I can see reluctance there,but the silver coloured standard duty is very finely ground indeed. Am I missing something here ? As a mostly truck mechanic,Never Seize is standard issue,and makes a huge difference.
So would seem to me a bright idea. Comments ? Cheers.
Paul Manson I was also a heavy equipment mechanic/welder and believe in neverseeze but not on the thread of the Chuck or any of the precision parts of a lathe, mill, etc. Draws too much crud. Only a light wipe of machine oil. Just my opinion. Thanks
Neat, my profile photo is relevant!
I need to do this the bull gear on an old lathe I’m trying to sell. Everyone gets scared off by the 2 missing teeth.