How to Use a Dividing Head

[@mikemichelizzi2023]

Sounds like you have a denominator stuck in your throat...

[@zedo5851]

Hi trying to figure out how to calculate the plate I would need for 40:1 dividing head have to make a 32dp in a 13.5" diameter blank. Comes out to be 432 teeth I come up with a 54 plate move 5 holes per tooth. Or 0.09259 angular indexing? Please shine a light on this for me thanks in advance Zed

[@abdullahnaeem1129]

Want to purchase a deviding head

[@SteveKravetsky]

Just watched the how to use a dividing head video, since I bought my first new one yesterday, and need to set up for drilling a shaft at 45 degree increments. Knew NOTHING about, we are still wet behind the ears ! Me and my brother ,ages 63 and 62, have 2 years of light milling experience. Spent 2 hours watching and writing down. Should be able to do now. VIDEO WAS AWESOME !!! Thank you so much for !!!! Messed up getting links to formulas, will try again. GOD BLESS YOU FOR YOUR HELP !!!

[@t.d.mich.7064]

I learned all this in High School machine shop back in the early 60's. Used the knowledge several times through out my career in the shop also, as well as tying the head to the table lead screw through a gear train to cut helical spirals. Not used much any more. Thank you CNC

[@richardjackson4280]

It's been awhile since I've used the dividing head. Thanks for the refresher course. I haven't used one since my first machine shop job in 95. I have been spoiled by the CNC 4th axis. I was looking at dividing heads for the house and I ran across this video. Thanks for making it.

[@BladesIIB]

Thanks for the clear and concise video. I have a new dividing head coming this week. I have not used one for 25 years and this was just the quick refresher I needed.

[@micdal22]

I had no idea what a Dividing Head is, and after watching this video I am fully enlightened. Thanks a lot for a beautiful explanation.

[@CaptainSwoop]

Incredibly helpful and well explained ... Thanks! I really appreciate people like you who take the time to share their knowledge. I'm a 74 yo newbie and had no trouble following your tutorial. Maybe because I've just bought one and hang'n to give it a run. Greetings from Australia.

[@NickandMildred]

What a clear and concise description . Thanks for that , I can’t wait to get a dividing head and give it a go...

[@morkbov]

Gee. If I could clic 10 times on the LIKE button, I would have done so. Thanks for this very straight forward demonstration.

[@brucewilliams6292]

You always do a great job of describing how to get things done. Thank you.

[@RealJohnnyAngel]

Thank you so much. We just went over this in class and the old vhs was just an absolute Whirlwind of numbers thrown at us, but without clear visual explanation of the process.

[@ianjaymanolong443]

Thank you for the well explained video. Helps me a lot.

[@StuartdeHaro]

You're very welcome. Thanks for watching!

[@campbellmorrison8540]

Excellent thank you, I have just bought myself an indexing table and Im feeling more confident in giving it a shot having listened to this video cheers

[@StuartdeHaro]

I'm glad it helped. Let me know if you have any other questions. Thanks for watching!

[@campbellmorrison8540]

@@StuartdeHaro Thank you Well I have had a go with mine and the first pattern I needed was 7 holes. My head is 90 turns/rev and the only plate I have divisible by 7 is 21. so that gave me the fraction 6/7 or for this disk 18/21 BUT when I went to set the sector arms they could not be rotated that far apart without hitting the back of the other arm so I had to move the sector arm 1 hole past the position of the sector arm, what a pain. I wonder if you have similar problems for 7 holes?

[@StuartdeHaro]

@@campbellmorrison8540 Did you try rotating them both directions? You should be able to close them almost completely. Usually they have a bevel on the edges of each arm and that should be the inside edge.

[@campbellmorrison8540]

@@StuartdeHaro Thank you for your response. Yes I did. The bevels do face each other in what I will call the closed position. If I fix one arm at the zero hole on the 21 hole plate and then move the other arm around clockwise I can not rotate it far enough to get the beveled edge to the 18th hole. I could align the arm with the high side on the 18th hole but this limits the ability for the hand crank pin to engage although that is what I ended up doing and moving the second arm back a little ie using the bevel side for the start position and the non bevel side of the second arm as the finish position. From what I can see it only seems to be a problem with 7 holes what I may do is make a 7 hole / 21plate specific arm that is fixed just for this but its not like I need 7 holes very often.

[@StuartdeHaro]

@@campbellmorrison8540 Well that sounds inconvenient, but your plan sounds good to me. Good luck and let me know how it goes.

[@miguelcastaneda7257]

Good simple explanation...Great video..last time I used one was I'm trade school decades ago ..they taught with all the math that confused us all...your walk though is very good

[@p.m3735]

Excellent video, I have a dividing head that I now know is 60 to 1 , great information 👍 Thanks

[@engelbob8402]

Thanks Stuart. This is timely info for my yet to be used dividing head. Good explanation.

[@edwardkendall3905]

Great, clear explanation. Actually, that’s pretty much true for all your videos. Thanks

[@eddietowers5595]

Do more dividing head videos. I’ve worked in a shop that never used dividing heads, just rotary tables and spin indexers, for the most part. The shop was converting to all CNC when I left. There were literally a handful of manual machinists, at the time, and I never learned CNC.

[@timlovett2673]

What a great video. Easy listening voice too!

[@StuartdeHaro]

Oh stop! You're gonna make me blush!

[@marcmckenzie5110]

Stuart, I much appreciate your channel and learn from a born teacher. As a future topic my request is a piece that compares, contrasts, and explores the best uses of these similar fixtures: spin-index collet, indexed spin jig, and indexing rotary table. I understand how each one works, but it seems their function can overlap, and some clarity of use and application would be most helpful!

[@StuartdeHaro]

Nice idea, Marc. I'll see what I can do.

[@frankmora8336]

enjoyed the video, you presented very clearly. Understandable

[@hkruczek8725]

Thanks for this lecture, its been very informative.

[@tropifiori]

Thanks, I came across and old Brown and Sharpe Dividing head nd have sort of figured some of this out . This was helpful. Thanks Frank

[@StuartdeHaro]

I'm glad it helped, Frank. Thanks for watching!

[@billdlv]

Good explanation Stuart.

[@jonasanyaka780]

Good practical teaching

[@qcnck2776]

Thanks so much for the handouts!

[@aguycalledlucas]

Thanks for the video-very clear explanation.

[@adamzimmerman3356]

Great vid. Totally get it now. You r the best.

[@astiwahkiastitonto8393]

Is there any teal calculation for finding the milling cutter and depth of cut?

[@StuartdeHaro]

Teal calculation?

[@astiwahkiastitonto8393]

Sorry! I meant to write real calculations

[@rexnemo]

@@StuartdeHaro Yes he's milling a duck . There is a branch of math for calculating how to mill ducks it is called Teal Calculation . 🦆😁. I'll get my coat .

[@doughales6625]

Well done explanation. Thank you!

[@rogerdeane3608]

Excellent tutorial, thank you.

[@wayneg2139]

Great vid learned a few things. I'm working on building a Gingery book #6 dividing head with a 40:1 ratio. I hope to be able to cut change gears for the Heavily modified Gingery lathe I built. Before anyone replies to malign the Gingery lathe it is being built solely as a hobby, just something to have fun at. It works very well. I'm using it to work mainly cold rolled steel. It is capable of very heavy cuts for such a small lathe. (UP TO 1//4" deep in a single pass) The castings for it are aluminum from old engine pistons.

[@teddy0663]

Wowzers this was a great video going to save this for later🎉

[@tuffymartinez]

Thank You Stuart de Haro... Loved your show. Most I was familiar with. I recently volunteered to help a shoe repair shop. He had a very old & beautiful German stitching machine that stopped working. The old & worn micarta sacrificial gear finely gave out and stripped. For 3 months the repair work was holding the shoe with one hand while cranking the drive wheel with the other. The broken gear was 2" in dia. with a 96 tooth patterns. I could not figure out how to find a 96-hole pattern and I still do not know. I was able to find a nylon gear of exactly the same dimensions on eBay. It is a common gear used in RC cars and in Drones (I got LUCKY!!!). The machine is fixed and is working fine BUT I seriously wanted to know how to hit 96 holes? any suggestions? I was half way through laying out a 96 hole plate & use it on my spin indexer but found the nylon gears so did not need it. Stuart any thoughts would be very much appreciated. Thank You .... Tuffy

[@StuartdeHaro]

You wouldn’t necessarily have to have a plate with 96 holes. Since it's an even number it will reduce quite a bit. If your gear ratio on the dividing head is 40:1, your fraction would be 40/96. The lowest common denominator is 5/12, so you just need to find a plate that will allow you to make 5/12ths of a turn, such as 10/24 (10 holes in a 24 circle) or 15/36 (15 holes in a 36 circle). If you don't have either of those in any of your plates, 24 holes is a whole lot easier to make than 96! I hope this helps. Thanks for watching!

[@tinaliebe5118]

Man I wish I Listened to my math teacher back in the day 🧚🏻‍♂️

[@StuartdeHaro]

Same here. Got any questions that need clarification?

[@johnstrange6799]

I'd sure like to have one, but it's the kind of thing that can (and by "can" I mean "must") wait. Thanks for the video :)

[@ClownWhisper]

Okay is there a rule of thumb do you always keep the handle pin on the right hand side of the dividing arms but I guess that isn't so because as you turn it it will change to the left hand side I need to learn how to do this I absolutely have to learn how to do this and I have dyslexia which doesn't just affect reading and writing but affects spatial orientation so I'm going to have trouble with this. Once I get it down I'll be very good at it because I have to do it and I'm very stubborn but I am going to make a lot of mistakes I went out and bought a great big chunk of delrin and one of nylon and I'm going to slice it up into gear blanks to practice on that way I won't be ruining a bunch of crap. I live near an alto steel company they discount oddball cuts of delrin for like $0.50 a pound believe it or not so I get that kind of stuff for next to nothing so I'll be able to practice like crazy and I won't wear out gear cutters either. But this is something that I have to do any advice would be greatly appreciated

[@rexnemo]

Don't think of it as being to the left or right , it is more about backlash . So if you turn clockwise and then try to correct going too many holes by going back a couple of holes then the accuracy is lost . What we were told on our apprenticeship was to go right back and then repeat the turns . So if you have to for example go five holes on a thirty plate , which is 1.5 degrees , then clockwise or anticlockwise will give the same result in an opposite direction so it works either way . If however the handle slackens up then you have got backlash and need to go back about half a turn and then start again to move in the direction you want . I hope this helps ? Good luck .

[@melgross]

Great vid. But there’s an error about the Ellis head. It does indeed allow you to free spin the spindle. I would have to go and look at mine, but one of the two set screws on the flat of the top of the head is loosened. When loosened by the right amount, you can tilt the wheel down, which disengages the worm and allows the spindle to freewheel. Reverse to put it back. I suppose it’s possible for one of the generations of those heads to not have that feature, but I don’t know of any.

[@ArnoduPlessis-n2v]

How do you work out the holes on the indexplate for example if you have a 36 teeth gear on a 40.1 plate

[@StuartdeHaro]

@@ArnoduPlessis-n2v In this example, your fraction would be 40/36 which reduces to 1 and 4/36 or 1 and 1/9. That means 1 complete turn of the handle and then 1/9 of a turn. You just need to find a circle on your plate that is divisible by 9. For instance, if you have a 27 hole circle 1/9th of a turn would be 3 holes. I hope this helps. Let me know if you have any other questions.

[@mrmerkin6203]

Excellent! Thanks.

[@RockingJOffroad]

Stuart, I didn’t see you mention anything about locking down the worm gear before cutting. It is important!

[@captcarlos]

Hi Stewart, that dividing head looks like it needs some loving... Good explanation, thank you. I could look after her for you......

[@StuartdeHaro]

Thanks for the offer, but the college probably wouldn't appreciate their stuff going missing.

[@ironhead65]

Very clear, thank you!

[@GeneralChangFromDanang]

How would you recover and figure out where you were if you accidentally bump the sector arms while rotating it? Asking for a friend who will probably do this in the future at some point.

[@StuartdeHaro]

Tell your friend to pay attention to where the arms were at the beginning of the movement, so if he does bump the arms as he turns past he can put them back where they belong. If your friend is still nervous about it, put a mark on the plate with a grease pencil or something else that's easy to remove. Recovery after the fact is tougher. You could try moving back to the previous cut, making sure to remove the backlash in the gearing. You can verify with the cutter or an indicator as needed. Thanks to you and your friend for watching!

[@wajih9219]

Hi Stuart, This is pretty late and probably unhelpful, but you mentioned there was no way to disengage the worm from the gear, I do believe on that model, the set screw on the right (in relative to the shot you were speaking about it), you can turn it back, and then push the indexing plate forward, in a nodding down motion, and the worm would move off the gear. You probably knew that and just said that cause it’s easier but I hope it helps somehow! Best!!

[@StuartdeHaro]

I did not know that. Thank you. That is very helpful.

[@wajih9219]

@@StuartdeHaro yup! I love your channel btw. You are one of the most entertaining and informative ones!

[@magnusklahr8190]

Very good explation!!

[@jimpritz4169]

Sorry to be commenting on an older video but I have a question for you. I'm new to this dividing stuff so please bear with me. I have a faceplate that will thread on my dividing head after the chuck is removed. With this set up can I use the dividing head as a rotary table?

[@StuartdeHaro]

Hi Jim. Yes that would work, although it isn't going to be as low profile as a real rotary table. You also won't have degree marks on the table (unless you add them) so you'll have to do everything by angular indexing. Let me know if you have any other questions. I'm here to help.

[@lesthompson5907]

I have a 60 to 1 small gearbox . can I mack a dividing head out of that?

[@StuartdeHaro]

You could. You just need to figure out how you're going to mount the chuck on the output side and come up with a dividing plate, handle, and sector arms (not strictly necessary ,but helpful) for the input side.

[@jonludwig8233]

Thanks for the content Stuart! Could you do a video on how to align the dividing head on the mill? There are several videos online about indexing but not so much about getting the dividing head set up properly...

[@StuartdeHaro]

That sounds like a good idea. I'll add it to my list. Thanks for watching!

[@z-collector7518]

Thank you! Very useful.

[@StuartdeHaro]

Thanks. I'm actually going to post another one soon on getting one of these set up in the machine. Keep an eye out for it.

[@tomherd4179]

Clear video, thanks. I use mine so seldom I have to refer to my notes for a refresher. QUESTION; while watching your video you mentioned "dials". I was wondering the best mill tool to scribe a dial (being held in the chuck/indexer) using a vertical mill. Perhaps a thin small slitting saw?

[@StuartdeHaro]

They make engraving bits that are long and pointy D-bits (round bits that are ground to half their diameter). You could also take a broken endmill and grind it into a drag bit. Think about this like a shaper operation. You grind the bit so it will scratch the line in. The spindle wouldn't run in this case. You just orient the tool so it will cut and bring the table up to where it just scratches. I hope this helps. Thanks for watching!

[@tomherd4179]

@@StuartdeHaro Like the shaper idea. My mill has a DRO so limits could be set for the travel. THANKS!

[@tomherd4179]

@@StuartdeHaro Forgot to add - yes I have broken end mills :-(

[@matthewwarburton4492]

Hi can you help me please. I'm trying to cut 112 teeth into a wheel. With a 1:40 denying head with no look. The dividing plates I have are. A:15,16,17,18,19,20 B:21,23,27,29,31,33 C:37,39,41,43,47,49 Thanks Matt

[@StuartdeHaro]

I didn't see this comment until today. Sorry. Your fraction would be 40/112 which reduces down to 5/14 of a turn so you would need a hole circle that is a multiple of 14, which you do not appear to have. You can make a plate yourself. I recommend using a higher number multiple like 56 so it will be more useful for other divisions.

[@stevelescom4336]

What plate do I need to cut a 53 tooth gear on a 90 to 1 rotary table ?

[@StuartdeHaro]

You would need a plate with 53 holes (or a multiple of 53) since that is a prime number. The fraction is 90/53, so that means 1 complete turn of the handle and then 37 holes in that 53 hole circle. Of course, it could also be a 106 or 159 circle, but getting that many holes in the plate would be a tall order.

[@stevelescom4336]

@@StuartdeHaro Thanks for the info ..

[@rickstride7269]

sir, my gear reduction is 5/1.. bolt head has 6 divisions. 5 divided by 6 = .83 is it 8/10s of a turn seperation of sectors arms? thanks rick

[@StuartdeHaro]

That's a very low gear reduction. I would double check that before cutting. Regardless, 8/10 isn't going to turn out correctly. 5/6 is equal to 10/12, 15/18, 20/24, etc. You have to find a hole circle that maintains that 5/6 relationship.

[@rickstride7269]

Mfg by Kearney & Trecker, mod. K. Its called a universal spiral dividing head. I have a Bridgeport mod. J2 . Just want to perform basic functions. I don't have a driver to sync, for cutting spiral gears.. I hope the 5:1 will work. Thanks rick

[@JoelOPinto1]

No links. A question: based on your sheet, which row of holes (16, 18, 19, 21, 24) I would use for a 90:1 ratio 40/4?

[@StuartdeHaro]

You actually wouldn't need to use the hole plates at all. You would just turn the handle 10 times.

[@sas949]

Brilliant explanation, thank you very much

[@TomChame]

Excellent, thank you. I'm trying to decide between the type you've got in the video and a BS-0. I have enough Z to handle either. As I understand it the BS uses mostly proprietary attachments, tables, tapers, ect. I'd appreciate your opinion or pros/cons between the two.

[@StuartdeHaro]

Whatever you get, the principles are the same, so as long as it will hold your parts and fit in your work envelope, you should be good to go.

[@12345NoNamesLeft]

I can't seem to save the documents, only open them in google docs, but cannot simply save as a pdf. Settings OK ?

[@StuartdeHaro]

I'm not sure how that works. I'll check and see if there are any settings that I need to change.

[@BiddieTube]

At google drive page, on top right, click the Arrow that is pointing down. If no arrow, use save page as from browser, choose pdf. From browser, choose Print, and print as PDF. There may be others, depending on what you have, and you may not have these options also.

[@12345NoNamesLeft]

@@BiddieTube None of those options have worked for me. The address of the links end in "view" That makes me think it's view only permission.

[@BiddieTube]

@@12345NoNamesLeft The URL's end in /view for me also. But I have all above mentioned save capabilities using Brave browser on windows 7 pc. Most, if not all phones, pc's, mac and Linux equipment has "Screen Capture" and save capabilities. Try that option if all else fails. Or log in with a pc and save the files. Whatever you are using though should be capable of saving the PDF files. What kind of device are you using? Another option, if you have a google account, you must if commenting here, then click the Recycle icon at the top right to "Add to your drive", then download if from there.

[@sino-atrial_node]

Thank you

[@ShopperPlug]

is this similar to an ultradex?

[@StuartdeHaro]

I'm not familiar with that so I googled it. I saw a lot of rotary tables which can have dividing plates like this. The principle is the same. You just need to know what the gear ratio is.

[@StuartdeHaro]

@@ShopperPlug that's what the Google told me as well.

[@aniveshchaturvedi9886]

how can I do 1 Degree 45 minutes on (means 206hole on plate),please reply

[@mbogo123]

Hi Anivesh - Following Stuart's approach, if your dividing head's gear ratio is 40:1 then That'd call for a plate with 103 holes, which you might have to make. 1.75º (1º + 45/60º) is actually 1/would be 7/36 of a rotation (7 holes on a 36 hole circle): 40/360 + 30/360 = 70/360 = 7/36. Let us know if that works?

[@dudekulaakbar3094]

Please explain calculations if dividing head.

[@StuartdeHaro]

Do you have a specific calculation that is not already covered in the video?

[@wktodd]

hmmmmm, to me diffential dividing requires a dividing head with moveable plate and gears such that the number of divisions is the difference between the gear train and the conventional plate divisions . Differential division gives the possibility of dividing prime numbers (eg 127) without specific plates . This type of universal head can also be geared to the mill's axis to allow spiral and cam milling.

[@StuartdeHaro]

It's probably a nomenclature issue. I've always referred to that as compound indexing. Thanks for the reply! Time to go check my details and make sure I'm not a total idiot!

[@wktodd]

@@StuartdeHaro could be Stuart, but my Elliott DH manual refers to geared adjustment as 'differential' and, if you think about it, there is little that is differential about simple plate-hole dividing

[@mbogo123]

Great video! Bill or Stuart, can you say a little more about how to accomplish larger prime numbers of divisions? I'd like to make a 127 tooth metric transposition gear for my lathe, but it's not clear to me what I'd need or how to get that number of divisions.

[@wktodd]

@@mbogo123For a 127T gear, my Elliott requires a 39 hole plate, a 56T gear on the spindle, and a 24T on the plate driver shaft , and what ever intermediate gears to connect the two .The handle os then indexed 13 holes for each tooth. The 13\39 would give 120 indexes but the gear train retards the plate to subtract the fraction of a hole to give the extra indexes. If you think about it, the handle only ever makes40 revolutions while cutting a gear to cut more teeth it has to make more stops so the job that the gears do is change the spacing by moving the plate backwards to add teeth or forwards to reduce the number.. Most universal div heads will need similar settings.

[@mbogo123]

@@wktodd thanks! I asked Precision Matthews about 127t on their BS-2 FULL UNIVERSAL DIVIDING HEAD and they told me it wasn't possible, that I'd need a plate with a 127 hole circle. Good to know that at least some universal heads can do larger prime numbers of divisions.

[@buddhimanivantha6719]

Thanks

[@StuartdeHaro]

You're welcome!

[@abdullahalmasry6165]

thank you too much

[@AB-yu2tj]

I would like to know how to cut hellical gear with dividing heads.

[@StuartdeHaro]

In order to cut helical gears, the dividing head needs to be geared to the table so as the table moves the dividing head does too. This gives you a spiral. This is a pretty simplified version of the process, but hopefully it gives you the basic idea. Thanks for watching!

[@AB-yu2tj]

Thank you for your reply,. I seen some videos on it, but none really explain much. already, purchased the dividing head and gears. There are multiple angles involved, little confused, though I think I am getting it. Now I am trying to figure out how to connect the deviding head and gears with 1" shaft and bores to the 5/8" shaft of the x axis of the on the mill.

[@StuartdeHaro]

It definitely is not an easy setup. It's one of those that takes you all day to get right and then 10 minutes to machine. Helical gears were generally cut on horizontal mills with universal tables that could be angled, but a vertical mill with the head angled works too. Check out Ivan Law's book on gear cutting if you haven't already. Good luck! Take a video and shoot me the link when you're done. I'd love to see it.

[@AB-yu2tj]

Thank you for your reply. I figured they'll be a bunch of trial and errors. The way it's looking it might be awhile before I start it. I will look for the book you mentioned. I have not looked at the book yet. thank you. My camera that I was planning to do videos on was taken. I might have a new one by the time I start the helical gear. Happy holidays.

[@danielerasito7088]

Still confuse about the selection of the holes

[@StuartdeHaro]

Let me know what is confusing you and I'll try to help.

[@le3045acp]

love your videos i dont see the links

[@StuartdeHaro]

I'm putting them up when I get home from work today. They should be up in about an hour.

[@StuartdeHaro]

They are up now.

[@mariojacob363]

How about 50teeth sir

[@StuartdeHaro]

Pretty easy. Your fraction is 40/50 or 4/5 of a complete turn (assuming you have a 40:1 gear ratio). You just need to find a hole circle that is divisible by 5. For instance, in a circle of 20 holes, you would go 16 holes. That's because 1/5 of 20 is 4, so 4/5 of 20 is 16. Let me know if you have any other questions or need any clarification on my answer.

[@mariojacob363]

@@StuartdeHaro tnx,I'll check if there is 20hole circle plate

[@StuartdeHaro]

@@mariojacob363 It doesn't necessarily have to be 20 holes, just anything divisible by 5 so you can get 5ths of a turn. If you have a 25 hole circle, you'd move 20 holes for 4/5 of a turn. 30 hole circle you'd move 24, etc.

[@mariojacob363]

Yes,I know sir,but inoerder not to make 25 holes,I just do it ,in 20hole,plate plus 16, because we have 20plate hole circle,can it be done

[@mariojacob363]

We have 15hole plate also,

[@jamiebuckley1769]

wow its a good thing i know what your talking about since i own a dividing head and have used it many times but 4 the newbie you would have left them scratching there heads wondering exactly what you just said lol. there are charts on the internet wich simplifies and takes out the figuring it out wich makes it easyier for the newby.

[@colefournel5701]

i wasn't even tired at the beginning of this. 11 min later i need a nap

[@nealblackburn8628]

differential indexing is when you put some extra gearing in betwen the dividing plate and the output shaft what you are describing is plain indexing or simple indexing ...good video otherwise

[@nealblackburn8628]

you are using the word differential indexing when you should be saying indirect indexing.....differential indexing can only be performed on a universal dividing head and involves adding more gears into the process

[@biggreasies537]

Yes, it is obvious that he doesn't have a clue about what differential indexing is, it is a method to allow the indexing of prime numbers, it does require having a universal dividing head, where the spindle can be geared into the worm with change gears, best reference is the Brown & Sharpe book, "Practical treatise on milling and milling machines"

[@mariojacob363]

Gud dy