Regrinding a Hardened Dividing Head Worm Screw

The worm screw in my trusty Walter UTA 100E dividing head was damaged by corrosion, which I didn't notice until I recently checked it's indexing accuracy. This worm is dead hard and the corrosion quite deep, so reconditioning is probably only possible by grinding. However, grinding that worm screw is not as straight forward as cutting threads on the lathe. So I came up with a grinding setup that borrows some parts of my Deckel D-bit grinder. This setup is used on my EMCO V13 lathe. Also I had to figure out particular angles and the necessary lead screw gearing ratio, avoiding rare gears which I don't have.
The reconditioned worm is now probably as good as new and ready for another 50 years of service!

[@jimsvideos7201]

The process was engineering, but the result was surely art.

[@robinadair8631]

I love a quiet beer or two with you and Stefan... Conversation would be fascinating.

[@anengineersfindings]

:D Very kind of you Sir, but knowing Stefan and myself, the conversation would probably be rather silly and comical.

[@LikeFactoryMade]

Maaan, this video is awesome. Never saw so much engineering skills in one video! ❤️

[@fletcherbraylen7361]

you all probably dont give a damn but does anybody know a trick to get back into an Instagram account? I was dumb forgot the login password. I appreciate any help you can offer me

[@majorjason9640]

@Fletcher Braylen Instablaster ;)

[@fletcherbraylen7361]

@Major Jason thanks for your reply. I found the site thru google and I'm trying it out atm. Seems to take quite some time so I will get back to you later when my account password hopefully is recovered.

[@fletcherbraylen7361]

@Major Jason It did the trick and I now got access to my account again. Im so happy! Thanks so much, you really help me out!

[@majorjason9640]

@Fletcher Braylen glad I could help :D

[@arnljotseem8794]

Superb engineering work. You seem to always think outside the box. Thank you for taking the time.

[@davidtaylor6124]

Wonderful! The whole time you showed the grinding I was wondering how you were going to address the new 'A to B' ratio, or if it wasn't necessary. Onto part 2!

[@DavidSmith-ib5jl]

I have enjoyed your videos and your attention to details is incredible. I don't think there are too many people who have such a commitment to the quality work you do. By the way right after I saw this video I when to Craig's List and found a Maximat Super 11 for sale and drove 80 miles and picked it up. I have a Compact 9 which was a lot of fun for an retired guy. I did use to make a 1/8 scale steam donkey engine and a three truck Shay which runs on propane.

[@anengineersfindings]

Thank you for your kind comment, Mr. Smith. Glad you find my videos interesting. I hope you are happy with the Super 11. The Emco Machines are surely not at the level of, say, Schaublin but I am really happy with mine. ATB, Alex

[@Biokemist-o3k]

The dividing heads are so expensive and to have them be so far out is very disheartening. I am going to build my own so I can control my own quality. I am building my own tool post grinder and we shall see how it goes. Thank you for sharing the video.

[@udowillkomm1173]

Das ist schon grosses Kino, was Du hier immer zeigst....danke Alex.

[@Jimmy_McGinty]

Das war beeindruckend. Ich finde es richtig toll wie du komplizierte Prozesse verständlich vermitteln kannst,

[@brucewilliams6292]

I am in awe of your mastery of machining. Well done.

[@RRINTHESHOP]

Very nicely done. I was wondering about the increased backlash, next part, nice. Beautiful fix.

[@philiphahn1804]

I wish I could sketch half a nice as you! And a very ingenious setup. Thanks for sharing!

[@captcarlos]

Amazing ingenuity. I may have to rethink my aversion to tool post grinding. Thank you for showing us.

[@Aleksandar_Sladic]

Beautiful setup! Love your ingenuity & showing that even highest precision job can be done very simple using the most basic equipment. I definitely believe this is what it's missing in this over complicated world. Thanks for sharing your skills! Best regards, Alex

[@anengineersfindings]

Thank you Sir! I particularly like your expression "overcomplicated world".

[@ralphgoings2120]

Enjoyed, great solutions to difficult problems. Waiting for part 2.

[@joemiller105]

You're videos are very interesting, looking forward to part two.

[@russellforrest1730]

Genius improvisation!

[@lukaszpanfil1911]

As always marvelous work. I'm waiting for next episode. In the same time it inspires news ideas in my head. Thank you!

[@fredgenius]

I'm blown away!!! Thanks, you inspire me to greater things.

[@SailingYachtDreamcatcher]

Excellent content, as always! Thank you!

[@garym1550]

Beyond excellent! You have set for yourself a very high bar to meet, if not exceed, in the other half of this repair. Looking forward to your delivery.

[@Engineerd3d]

Man Stefan was right, this video is well worth watching. Awesome work.

[@HP_rep_mek]

Very impressive as always👍 I really like the Deckel grinder spindle being used on the lathe🙏, I will probably borrow that idea sometime😇

[@rprichard8452]

You got some mad skills brother! My math is 1st grade (school grade that is) compared your’s, and I’ve been a machinist since 1972.

[@TheKnacklersWorkshop]

Hello Alex, Very interesting video and great to see you reusing/repurposing the equipment you have in your workshop (The Deckel)... Take care. Paul,,

[@benrivenbark]

Wonderful content as always. I am always looking forward to anything you make. I'm kind of surprised to see you didn't cover the ways on your lathe when grinding, but I'm sure you took that into account.

[@tooltimechris7217]

Really nice project! Job well done!

[@guyloughridge4628]

This was a wonderful video. Your math skills out outstanding and your solution for a problem was equally outstanding. Keep making videos. Your KZbin content is very much appreciated

[@anengineersfindings]

Thank you Sir!

[@kevinrblodgett]

Excellent content, looking forward to part two

[@hereticswissery9010]

Excellent work and video as always

[@tomsemo8186]

Excellent video. Glad i found your channel.

[@petera1033]

Thanks Alex - interesting job and solution(s)

[@mudnducs]

Very nice job young man. 🙂

[@janzimmer5128]

Danke für das informative Video, echt interessant was doch alles machbar ist.

[@queuing89]

Excellent work

[@roylucas1027]

Great video. Skills way above my level, but very interesting. Take care.

[@benz-share9058]

(20:45) I always wear safety glasses when I watch your videos! Thank you Alex for the instructive and enjoyable video. I look forward to part 2.

[@anengineersfindings]

;D

[@anengineersfindings]

:D Next time you'll probably need safety shoes too!

[@andyZ3500s]

This has to be one of the oddest set ups I've ever seen. Great results, I am heading to part two.

[@josealcaraz1575]

In the Olympus of my God Stefan Gotteswinter there is a new God, I love his work, I undoubtedly learn a lot, although I see everything with the google translator, it is evident that he has great dexterity in the technique of metal scraping, I would give anything for a video of him giving a detailed class.

[@anengineersfindings]

Thank you, that's very kind of you Sir. I hope not to disappoint you in the upcoming videos.

[@ran0mize609]

Erstmal wow, super gelöst und um da zu folgen raucht einem echt der Kopf :) Die Tangens Methode findet heute direkt ihren Einsatz Vielen Dank

[@SamEEE12]

Tidy job, the enthusiasm and good humour is infectious :-)

[@anengineersfindings]

Thanks, glad you find my attempted humor not mind numbing.

[@stonecraft745]

Man du bist in Chiprag!! Glückwunsch!

[@peirossmallhomemachineshop5364]

Awesome retrofit of a dividing head. Congrats ... from Genf :-)

[@woodscreekworkshop9939]

Beautiful work! 👍🏼😳

[@wktodd]

Watching with interest . I have a small rotary table with a similar (worse!) problem.

[@rodneykiemele4721]

Ingenious idea

[@Tonioostendorp]

Great work!

[@3ltrchris]

Great video, interesting work arounds. You should have a lot more than 5k subs.

[@wktodd]

Patiently awaiting part 2 ;-)

[@nathanquinlan2719]

Actually I subscribed because you are the person to take apart delecate machinery for fun. ;)

[@weldmachine]

I did not come here so much to watch you grind the Worm Gear. ( even though i still watched the whole video, LOL ) But came here to find a great new channel to subscribe to. Looking forward to watching more of your work. Peter.

[@madinatore]

looking forward to part 2

[@thomasstover6272]

Savaged beast soul soothed. Thanks!

[@marianodiaz461]

that is a very good Idea!

[@AlexCNC]

Awesome work!

[@anengineersfindings]

Danke Alex!

[@jawadibrahim2367]

Beautifully done, quite an inspiring endeavor. I hope I can pursue hobby engineering sometimes in the future because I too wish I could try and make cool looking -scrap- parts :-D

[@jpgarcia90]

this is nuts, I love it

[@jimsimpson8663]

Hi Alex, that was a good way to solve this problem ! I like the way you modified the lathe ! I have modified my lathe to cut a scroll (spiral) to make a 4inch scroll chuck using external jaws from a small (2.5inch ) chuck I already had

[@anengineersfindings]

Awesome, I'd really like to see your setup! Cheers. Alex

[@jimsimpson8663]

Hi Alex, thanks for your comments . I will need to contact you via email so I can send you pictures of my lathe set-up. My email address is. [e-mail] I live in England

[@adrianfernandez1806]

exelent job my friend

[@sma11]

WOW, great problem solving.

[@Molb0rg]

good video, sweet reuse parts at hand, and making new jigs. what I was missing is setting the angle, was important for the job and sure options are available but still interesting how it was done in your case. protractor and sine plate - yeah, but what u mention - eh? So for less knowledgeable guys, it was an interesting piece of information missing there.

[@thanos_vgenis]

Excellent, many thanks!!

[@guywihn1658]

This was wonderful!.. thank you

[@mykedindeal]

Oh boy.You're good👍

[@dsalafydsalafy1799]

great content.....!!!

[@turningpoint6643]

As always Alex extremely interesting and very well thought out problem solving. I think I now have to move your channel up into the top 5 I know of on YT. And I'm very much looking forward to part 2. It's an interesting accuracy problem to solve with what's available in a home shop to build a new worm wheel from scratch to the accuracy level that Walter head requires. No doubt Emco would have had some high accuracy specifications on that V 13 lead screw. But have you figured out how to map the unavoidable errors that might be present from new and in it's current used condition? Since those worm threads were so short then that's a big help and may make any errors that might be present become insignificant and any pitch error would of course be reduced by your dividing heads worm and wheel ratio. Moore Tools in there book Foundation's of Mechanical Accuracy go into some detail of the issues they had while trying to produce "perfect" hardened, ground and lapped feed screws for there jig borers and grinders. And while they could measure the screws and nut's lead/lag errors into the low millionths of an inch, they were unable to completely solve the problem prior to the invention of high accuracy dro's and then later cnc. But I'm sure your possible lead screw errors must have been something you had already known about and considered.

[@AJR2208]

That was excellent Alex, but way too short (excuse my selfishness here). The technical planning and setup is not so simple, but you really made it look that way - well done. It's good you can reproduce you own worm wheel to match this. Looking forward to part 2. Stay safe and well :)

[@seppmittermeier3444]

Servus Alex, sehr interessant!

[@anengineersfindings]

Danke Sepp! Herzliche Grüße!

[@machinenutdel6764]

Most enjoyable

[@robinadair8631]

Even better! 🙂🤣😁 (Thank you for your reply)

[@paulmace7910]

Wow. Just wow.

[@6NBERLS]

Most excellent. A little beyond me though.

[@thiagosanchez4453]

Impressive 🖖

[@lrakschmidt2880]

Thanks so much for letting us look over your shoulder. Quite a treasure. I am wondering if you have done anymore scraping of steel? - the trick you came up with is a valuable addition to the art.

[@anengineersfindings]

Thank you! Scraping jobs come and go occasionally, however nothing proper like a whole milling machine reconditioning ;)

[@greglaroche1753]

Thanks

[@francoismaltais7798]

Ha, that nasty number Pi always get in the way! You have fun, we have also, thanks alot!

[@francoismaltais7798]

And a number 2 is following! What a treat you give us!

[@ran0mize609]

π = 3 Take it or leave it ;)

[@anengineersfindings]

:D Sometimes Pi=3 would make life much easier.

[@SteveSummers]

Nice work, I dont know if I would have been brave enough to attempt this.

[@anengineersfindings]

Thanks Steve, but you cannot say you not brave enough if you have a wife who threatens to cut you ;)

[@mpetersen6]

Nice work. The limitation here of course is just how good is the lead screw. One time I had to install new bearings on the 4th axis of a Veryical Machining Center (K&T 400). As luck would have it the main bearing was in good shape (a Kadon roller bearing with the rollers inclined at 45° with the rollers alternating their orientation. The main problem was the seal which was letting in coolant. After putting the table back in the worm screw needed to be put in. K&T did something really clever. The Worm Screw was made with a Variable Pitch that allowed for setting the lash in the worm drive to the required specifications. It's too bad that a screw like that is not used in dividing heads. Not that it would have helped here.

[@darrenfloen2693]

Hi Alex. Exceptional work! When can we expect part 2?

[@anengineersfindings]

Hi Darren, thanks, won't be too long. Another month or so, sorry, currently I'm quite busy with other jobs.

[@darrenfloen2693]

@@anengineersfindings Thanks! (and more V13 videos please)

[@pyrobeav2005]

"Hope you're all wearing safety glasses!" I'd be lying if I said I didn't squint and flinch at the sparks...

[@DrKnow65]

How is the accuracy of the lathe lead screw as it is the "master" for what is now ground into the worm gear? I suppose the positional accuracy of the dividing head will let you know the condition of the lathe lead screw... I suppose it then becomes a challenge of metrology to isolate where error is induced. Very professional content, glad I'm subscribed :)

[@Gottenhimfella]

I guess the initial running of the indicator along the thread showed there was very little accumulation of pitch error, but the regular cyclical error (I guess) might have been due to the mating faces on the thrust bearings on the lathe's leadscrew not being sufficiently orthogonal... I assume they are plain bearings as usual.

[@sblack48]

That was fucking incredible

[@DonStinger]

Nice Job and a really nice video! A bit of constructive criticism: I hope that you set the flank angle on the spindle housing of the deckel spindle and only showed the method on the tool post for video purposes. Otherwise you have to hope for a parallel surface on the quick change tool post an putting the swivel fixture exactly parallel in the holder. The axial runout of the original worm is unknown. You measured the combined deviation of the worm screw and the setup on your lathe. Meaning the pitch deviations of the gears and the lead screw. You can however still check the pitch deviation of the reground worm screw statically against you Heidenhain dro. Would be really interesting to see. Greatings from a german colleague ;)

[@reiniertl]

Awesome work and great explanation. Only complaint, not protecting your lathe ways during the grind.

[@sebastienlambert1976]

The reason why you got 25 micron is because you measured it on the tread face, so it is not a real runout. And because of the angle of the tread you get a bigger movement . 😊

[@ZeRo8625]

Stefan gtwr sent me here 👍

[@nefariousyawn]

That was incredibly satisfying to watch. Did you run the indicator on the screw after you finished grinding it?

[@Molb0rg]

oh yeah, that is another thing missing in the video - would be interesting to see

[@akfarmboy49]

lots of corrosion on that worm gear, new worm unavailable?. very interesting project. it reminds me of a factory that built navel ship gun factory tour i was on 35 years ago. they were grinding 6 foot radius gear quadrants with dual grinding wheel swiss made grinding machines custom made. i always enjoy your projects. you are using a cupped wheel, I was expecting you would use a flat face wheel. or you tip your grinder to make grinding wheel face parallel tooth face? I might get one of those D model tool and grinders not the original .

[@Ryan-dz3jo]

Fantastic video and thanks for sharing the caculations, I expected you to have the late ways covered while grinding, maybe not a concern?

[@Gottenhimfella]

I guess with a high quality CBN wheel there is very little release of abrasive media, also he arranged it so the spark stream was away from the bed, but like you I was still somewhat surprised. Especially at the end, with the conventional wheel...

[@Gottenhimfella]

On reflection, even the debris from the steel workpiece would be highly abrasive because of its hardness...

[@craigwalker3256]

holy fuck you're a genius!!

[@bigwave_dave8468]

Top notch work! Is there any reason you did not consider using a VFD drive on your V13 to slow the spindle? I have a Super 11 (little brother to the V13) and the origninal motor was wound as a 3 phase motor which works fine under VFD operation. At the 55RPM gear setting, I can lower the drive frequency to significanly lower RPM. Just for fun, I set the VFD to give 10 RPM. It appears to work without issue.

[@Elektronaut]

Spannend! Wo ein Wille da ein Weg ;-)

[@keithbr9530]

Remember to cover slide ways when grinding !

[@rickoshea8138]

Nice! Don't you mind grinding dust fall onto the lathe bed?

[@chrisstephens6673]

Who can say anything better about your video than 👍👍👍👍👍👍👍👍👍👍👍👍👍👍👍👍👍👍👍?

[@ArseniySorokin]

Great project! One question though - why making this screw from scratch would be so diffucult (in comaprison to grinding it)? You already got the correct pitch - couldn't you just make a new screw? Or the worm gear couldn't be salvaged anyway?

[@anengineersfindings]

Good question, however, the worm wheel is not salvageable in my opinion.

[@thiagosanchez4453]

🤯

[@FCleff]

Savage beast with soothed heart here..........brilliant, brilliant, brilliant but my personal Butt-O-Meter hit 11 just from watching! One question; any fear of the HARD "unobtainium" and aluminum oxide dust resulting from the chamfer operation getting into your V13's nooks and crannies?

[@accuracymark]

Yes, was concerned about the decrease in pitch diameter with regrinding. Did ever consider a spray type weld built up and then grind to sec?

[@Gottenhimfella]

The centre distance of the dividing head wormset is adjustable to take up wear, and in any case he is making a new wormwheel, so he can make its teeth thicker by the same amount he took off the worm.

[@anengineersfindings]

@@Gottenhimfella Perfectly right, at least that's the plan!

[@manusholm3536]

im curious about the rope drive belts. can you mabe send me some close up photos. im intrested in making some from scratch for several aplications.