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Universal dividing head

Here is just one of the stumbling blocks on any mill. This is the first page of TWELVE pages from Cincinnati - each entry is another four gear ratio - the reason for this being the LEAD has to be a near as possible to being correct to suit the helix angle(s) of the helical pair

About 2800 entries in this document

Cincinnati Leads_01.jpg

Good stuff here from 12 years back on a K&T

Helical Lead? 30T drive gear K&T



Related chapter here starts on page 291

A treatise on milling and milling machines .. : Cincinnati Milling Machine Company : Free Download, Borrow, and Streaming : Internet Archive

Have fun
 
My mill is 5 tpi so it would be 40 divided by 5 gives me 8 so i believe my helix lead is 51in. So i guess i would 51 by 8 use that and figure out my gear change
 
Mr. Buckingham wrote this down for us in his related book - might be helpful

Helical Math A.jpg

Cincinnati says this for 51" even - but they are talking 4 TPI table screw

Gear A is 51
Gear B is 24
Gear C is 48
Gear D is 22

And no, I don't know exactly where those four gears fit :D

Here are some quick shots from instruction side and from around 51"

20200731_145509.jpg20200731_145551.jpg

If it turns out that way, gears for 63.75 lead in these tables do a 51" lead on a 5 pitch table screw, and the gearing for that is

A = 55 teeth
B = 22 Teeth
C = 51 teeth
D = 20 teeth
 
I know the Cincinnati mills table leed is 4tpi. .250 on the dial the gears i figured out on my mill having 5tpi if i did it right are 103,24,42,28 i would have to make the 103i still have to install the universal head and go 1 to one and count the revolutions on the table to one revolution of the dividing head for the leed
 
Mr. Buckingham wrote this down for us in his related book - might be helpful

View attachment 295447

Cincinnati says this for 51" even - but they are talking 4 TPI table screw

Gear A is 51
Gear B is 24
Gear C is 48
Gear D is 22

And no, I don't know exactly where those four gears fit :D

Here are some quick shots from instruction side and from around 51"

View attachment 295449View attachment 295450

If it turns out that way, gears for 63.75 lead in these tables do a 51" lead on a 5 pitch table screw, and the gearing for that is

A = 55 teeth
B = 22 Teeth
C = 51 teeth
D = 20 teeth

i wounder how they figured that one it would be interesting to see all the nomenclature
 
were does the 1.25 come from just trying to understand


Cincinnati's tables are based on 10 (.25) times 40

Your 5 tpi mill is based on 8 (.2) times 40

8 times 1.25 is 10

Just a way to be able to use the Cincinnati tables to find gears that work with a 5 tpi milling machine to generate the leads you want
 
Cincinnati's tables are based on 10 (.25) times 40

Your 5 tpi mill is based on 8 (.2) times 40

8 times 1.25 is 10

Just a way to be able to use the Cincinnati tables to find gears that work with a 5 tpi milling machine to generate the leads you want

I figured it out what you did thanks for the reply i will still have to make a couple of gears so are you machinist by trade i worked in a job shop for 10yrs ran cnc but now i do refinery machining iam making a gear for a lathe right now i made several spur gears this will be my first attempt on a helical gear i have s an old Cincinnati mill book coming it is from 1951 it might be the same one you mentioned thanks again for the help 😀
 
Stopped being paid to be a machinist in 1972. At 80 years of age now it is just a fun past time that keeps the gray matter functioning. Here is the old coot standing on his 15,000 lb Jig Bore
DCP_1135.jpg

Was in Sedro Wooley in 1992 buying a 1935 Packard Super Eight. :D

I figured it out what you did thanks for the reply i will still have to make a couple of gears so are you machinist by trade i worked in a job shop for 10yrs ran cnc but now i do refinery machining iam making a gear for a lathe right now i made several spur gears this will be my first attempt on a helical gear i have s an old Cincinnati mill book coming it is from 1951 it might be the same one you mentioned thanks again for the help 
 
Probably when you get right down to selecting gears you will have to do some experimenting

The reason for this is what was scanned and sent to you probably only applies if you had the type of "driving mechanism" shown on that scan

Looking on Page 341 here was an eye opener - this is from the days (1916) when the gear train was out in the open - no "driving mechanism" involved

A treatise on milling and milling machines .. : Cincinnati Milling Machine Company : Free Download, Borrow, and Streaming : Internet Archive...

Just look at the entry for 4.040 lead (at the top of the page 341) - it says entirely differing gears compared to what it says for that same lead on what was scanned and sent to you
 








 
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