Missing Back Gear Tooth. South Bend 13 (pt6)
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- Опубликовано: 16 июн 2022
- When the back gear was engaged durring the small test drive I did prior to buying this machine, it made a slight knock per revolution of the chuck.
I guessed then that the bull gear or cone gear had a damaged tooth, now is the time to see what I could do to fix it.
Apart from a bit of a cockup I made when I started my first cut, the tooth would have been right on the money. OK… so I made a mistake by forgetting to check the milling machine was properly secured, but its done now. Lets see how long it lasts... 
Хобби
Absolutely phenomenal work (ignoring the whoopsie of course, but we are all only human). Can't believe after all these years of watching YT machining community videos that I have never stumbled upon your channel. I've immediately subscribed, toggled the bell on, and I am now anxiously looking forward to enjoying your entire portfolio of work. 👍👍😎👍👍
Hi, sorry i didn't reply, I missed your comment. But I thank you for your kind comments. Cheers
Great job on the repair, Paul. The method you used to index and cut the tooth is very clever! Looks like the gear should work a treat.
(Don't sweat the witness mark... Gives it character!)
Hi, thanks
Paul, I'm very impressed by your use of the involute principle to progressively cut the profile. I've seen other methods - base circle and tapes or wires, calculating offsets and using a slitting saw - but this is a new method to me.
Hi Bill, I’ve said it so many times - there’s always more than one way to skin a rabbit. regards
I zip-tied a spring to keep pressure up on the pin to disengage the back gear. Nothing sucks more than having a nice cut going and it just slows down and blows up an insert. On the other end of the spectrum, I have a bungie cord to keep the back gear engaged.
Hi, sorry i didn't reply, I missed your comment. Thank you I might even need to use that idea if I have problems. Cheers
Nice! As I am going through my South Bend 744 9a, I have found 3 gears that need attention, the two back gears and the bull gear. The small back gear is a loss, so I will replace that, but the bull gear is missing 2 teeth and the larger back gear 1. Now I will fret over whether to try and find those as used parts or whether to try and repair those 3 teeth for about a week before I do anything. Awesome video as always!
Hi. Thanks for watching, one thing I will say about this method of repair is that the tooth is not a precise shape, but it still works well, albeit a little noisy until it’s worn in, then it’s as good as new. All the best.
Smart idea to align the tooth using two blocks!
Hi, thanks
Don’t fret about the lill oopsy! It gives it character! good job on the fix, it should work great 👍🏻
Hi, I did wonder if zapping a little blob of weld on the top would fix it but I quit while I was ahead. cheers
Beautiful work
Thank you. regards.
Ciao Paul, this is Alberto from AB-SHOP Italy !! Stopping by from Paul, of the Knackler's workshop !!! Wow, i have to say wow in front at this work: this is your first video that i watch and it is the first time that i see this type of repair without a dividing head: really a great job also with a nice and clear explanation too!! From today Paul you have a new subscriber to your channel, me !! A big Ciao from Italy Paul, Alberto.
Hi Paul. the gear works perfectly well, my next video ‘an update’ will show up a few more horrors though. regards.
As an owner of several old lathes I know missing teeth are quite common, this really looks like a very do able method of repair, thank you.
Hi, you are very welcome.
That's a nice repair even with the oops.
Hi, thanks.
love this approach. in the past I have had some success welding in a new tooth and using slitting saw and 60° AND 45° cutters to shape. I will definitely keep your techniques in mind for future repairs
i hope you get a chance to do a follow up video in the future to show how it holds up also
@@craigtate5930 Hi, the slitting saw process is pretty much the same thing. Regards
HAHA MUNTED! Love that word.
Perfect repair though!! Oops and all.
Very good technique to line up the cutter without using a dividing head or special tooling.
This is why your channel is one of my few favourites!!
Hi, that phrase Munted is one I picked up in New Zealand, it sort of hits the mark nicely. cheers.
Lovely job.
Great video! I never would have thought of doing it like that.
I especially liked your single point dovetail cutter.
I destroyed a couple of change gears off my Atlas Lathe beyond repair so I found a involute cutter set on eBay.
They were not very expensive and I made some new gears from scratch out of brass. Way better than the original zermak stuff.
I have a rotary table I could tip up on its side to use as a dividing head.
Slotted the key way using the quill on the mill like a slotted.
Came out ok.
Worked great.
Great Job. This ist Dentist Work. Perfekt!
Hi, thanks, cheers.
A very clever way to repair a gear. Never seen like this before and can be done with seemingly little effort. I pay respect. Greetings from Germany, Raik
Hi, Thanks for your comments. Regards
WOW!!! This is fantastic!
Fun to see your approach! I would have gone for bronze braze but yours is better. The way you setup that gear on the mill is brilliant!
Hi, my first thought was to go and see a cast iron welder when he told me it will be £250+ to weld up the tooth I had no choice but to use plan B. Cheers
Your creativity knows no bounds. Thanks for sharing.
Hi, thanks for watching. cheers.
Excellant repair !!
Always a pleasure to see a new video from you - thanks!
Hi. you’re welcome.
Paulo, tu sabes que ese engranaje no quedo con la resistencia necesaria debido al error en el corte en la parte superior, hubiera sido más honesto de tu parte realizar nuevamente la reparación desde cero, hasta conseguir un resultado correcto y resistente. Saludos
Very nicely done
Hi, thanks
that is a great fix, realised with intelligent solutions given limited tools - kudos! I have the same problem - on a south bend back gear (10K in this case). I'm wondering how important the dovetail is, structurally - a square section would be so much easier ;) Also since there's no load on the top of the tooth, why would you not put the grub screw - or two in from the top? Did you consider brazing or silver soldering it in?
thanks for the upload, another trick learned !
Hi, glad you enjoyed.
really clever and good to watch
Hi, thanks
That was an ingenious repair Paul, you could call the cockup a makers mark. Would never thought of that myself, thanks for sharing.
Hi, Thanks David.
That is absolutely genius. Bravo.
Hi, thank you. regards
Lessons were learned but such a good job! Simple and efficient.
Hi, thanks for watching, cheers
Nice work
Hi, thanks.
Very nice👍👍 work
Hi, thank you.
Excellent! very clever
Hi, thanks.
Very clever. Thanks for sharing!
Agreed, VERY clever! Les
Hi, you’re very welcome.
First off I really enjoy the look, feel and pacing of your videos. There's a good serving of "meat" without a lot of "parsley" filler.
Next is the wonderful analysis and thoughts on how to place and hold items. As any machinist knows it's not about the metal removed but the setup details before the power is turned on. You really hit the bell with the setup details on this one. I learned a bit more than usual from this video which I hope I can remember when the need comes up in my own shop. The "trapping" of the gear with the blocks engaging the lower teeth is brilliant. Matched by the way you picked off the flanks to mill the new tooth.
Keep up the great work and I wish you many more subscribers. And yes, I think my stomach turned over as badly as yours when the tool took off sideways... A feeling only another machinist would understand I'm sure... .:D
Hi, Thanks, I’m glad you enjoyed the video, yes I’m surprised it didn’t bust the cutter too. Cheers
Interesting way of tooth repair; thumbs up
Hi, thank you, regards.
Hello Paul,
Great stuff... I really like the logic you followed, it worked well. See you on the next one.
Take care.
Paul,,
Hi Paul. Thanks I think quite a few people are going to try this one. regards
A bit more JB Weld on it and it will be fine.👍🏴
Hi. I just used up the last bit. cheers.
I love your videos thanks for sharing. The mistakes just remind us your human.
Hi, thanks
So what's a small mistake between friends ! 😁Very well thought out and machined and very informative.Thank you for sharing.
Hi, you’re welcome. cheers
Rustinox sent me. Great channel, and a great repair 👍 🇬🇧
Hi, glad you enjoyed it, cheers
i like your indexing system. will use it in fiture. had to coppy a gear that i couldnt get the tooth count in my rotary table without serious mucking about. ended had to buy one. could gave used your system and a nother gear as index wheel.....nect time.
Hi, glad you found it useful. Cheers
Brilliant!
Hi, thanks.
ΕΞΑΙΡΕΤΙΚΉ ΕΡΓΑΣΊΑ!!!
Hi Paul. Thanks for showing the method you used. Very good. Also for showing your mistake, which many would have covered up somehow.
Regards.
Steve.
Hi, thank you for your kind comment. Cheers
Niece repair Paul. Exactly how I saw my dad do it on a clock wheel only press fitted and filed to shape by hand.
Hi Tony, It just goes to prove that nothing in machine engineering is new. Regards
@@Thesheddweller Or sound engineering principles will stand the test of time.
Great work sir, hate moving the wrong wheel or just slipping up and making a nice fix into not such a nice fix, but looks like you caught it quickly enough to avoid catastrophic damage, could have slaped some JB Weld in that divot on side of that tooth, stuff is strong 💪, thanks for showing us that no one is perfect and we all make mistakes 👍
Hi, thanks and cheers,
Nice bit of work and really great technique. I have done a similar repair on a SouthBend, but tapped a few screws, brazed and filed to form. It is great to get it back into production. anyhow. enjoyed, cheers!
Hi, thanks. Cheers
Agreed, a good job well done. I drill and tap for a couple of grub screws, then bolt on a couple of thin plates, fill with braze and recut the teeth with an involute gear cutter or home-profiled fly-cutter.
One gear I had just had screws loctited in place and filed to shape. It never failed.
@@oliver90owner That sounds like a good idea.
Still a very good job and it works so I would call it a success .
Hi my thoughts exactly, cheers
Nice tooth repair, very incisive.
Hi, thank you.
An intelligent and pragmatic approach, but i bet it will always irk you when you see it.😉
Hi, thanks, I will probably forget its there I’m old enough for that to happen,😁
Clever solution.
Hi, thanks
Very different approach and something I would never have thought of.
Simply brilliant .
Regarding the cockup , as you had made the tooth from steel, what about using a mig and slowly carefully build it up without putting too much heat to mess up the JB weld.
And machine it again as before ?
Just a thought
Hi, thanks, I had considered that very fix, but I’m not prepared to upset the apple cart so to speak. regards
Excellent dentristy~!! I wonder why you didn't braise the tooth in
Hi, The reason why I didn’t Braze it in is mainly due to the risk of cracking the gear. The tooth can only be brazed in or one built up using brazing rod if the whole casting is first heated to a given temperature, then using a concentrated quality flame like using Oxyacetylene to stroke the rod in. I haven’t got such equipment. I hope this goes a little way to explaining why I didn’t do it that way. Cheers
You're right, Paul. For these low speed geas it doesn't matter much if there is a little damnage on the tooth.
Hi, true, very true. regards
Bozo visited your shop I see!
Who’s bozo?
Doh.. I’ve just realised what you mean. Yes I had a visit from bozo.. 🤪
nice one.
On the subject of the wandering cutter, no that the tooth is steel would it be possible to weld in the missing material and then machine it back again...just thinking out loud incase it had somehow made a mole hill out of a mountain
fantastic series btw thanks for sharing
Hi, yes it would have been fairly easy to weld, but the heat could have affected the resin bond and I didn't want that. cheers.
@@Thesheddweller that's a very good point , I suppose braising the tooth in. The first place might have worked but you still run the risk of melting it again if you weld.
Thanks for sharing
RightOn! (American for "FarOut"...)
Hi, Thanks. Glad you enjoyed the video. Cheers.
Well using a dovetail to repair a gear Ina bull tooth is brilliant! If I had seen this technique 4 months or earlier I could have repaired a broken bull gear for my company and saved then 20,000 dollars us in lost contracts and a new parts I would have been a hero, as it stands the welder tried to weld in a new tooth and cracked the entire gear.
oh well, next time I suppose!
Hi. Glad to be of service, cheers.
If you had the broken off segment of tooth do you think it could have been brazed back on and operated successfully? Asking for a friend.
Hi, the problem is, getting it done professionally is very expensive. Brazing is possible provided the main cast component is heated beforehand to try and prevent the component cracking, but I’ve also heard many stories of complete failure. cheers.
I'm sorry you did a great job, but it wasn't easier and safer to refill with cast iron electrodes or better still with AISI 309, it has perfect adhesion with cast iron and is workable.
What a huge job you did, congratulations
Hi, I don’t have a TIG welder and a nearby cast iron welding specialist was charging £250+ (€300+)to do the job for me. this was my safest and cheapest method, thanks for the info though. cheers
Well done shed dweller! :)
Hi, thanks
Brilliant method of indexing the gear teeth Paul. That out of the box thinking at its finest!
Was Heath involved in this ? 🤔🤔🤔
Cheers Nell
Hi Nell, well we sort of bounced a few ideas between each other his idea helped. A guy just the other side of town wanted £250+ just to weld it up. guess what, I’ve still got £250 quid in my pocket. cheers mate
@@Thesheddweller what is he, a dentist? They charge those sort of rates 🤣
Given the tooth was mild steel could you have tig welded a repair on the tooth with minimal heat?
Hi, I can’t afford a TIG welder. cheers.
@@Thesheddweller a machine shop with out a welder?
@@TheModelmaker123 Hi, I have a welder, I don’t have a TIG welder.
Nice repair!!!
Hi, thanks. Cheers
👍
😀
Gear Dentist 😉👍
Hi, i wish I had a dentists pension.
As the repair is mild steel, you can just fill the mistake with a blob of weld.
Hi, Its possible, and I did consider that, but I didn’t want to risk upsetting the apple cart. cheers
Warum machst denn weiter, nachdem dir bei 10.15 dieser Fehler passierte?
Hallo. Es tut mir leid, dass ich zu spät auf Ihren Kommentar geantwortet habe.
Nachdem ich so viel Zeit damit verbracht hatte, den Zahn einzupassen, konnte ich mich nicht mehr dazu entschließen, den Vorgang noch einmal durchzuführen. Vor allem, weil der kleine Schaden an der Oberseite des Zahns nur geringe Auswirkungen auf die Funktion des Getriebes hätte. Seit der Reparatur funktioniert es einwandfrei. Grüße
Never heard the term G clamp used before, are you sure you don't mean C clamp?
Hi, in the UK they are G clamps. cheers