Vertex HV6 - Corrected Division Table plus universal dividing spreadsheet

Trying to cut a 1.5 Mod 13T gear, and produced two scrappers.

Thought that it was my miscounting the number of holes, but the second attempt still resulted in the final tooth being much thicker than the others. So it looked as if the increment was a little too small.

Spent some hours setting up a spreadsheet to check the Number of Turns and No. of Holes for the three Division Plates and the various Divisions.

According my calculations, the movement should be given by 6 turns and 36 holes on a 39 hole Plate, not the 6 Turns and 30 Holes shown in the manual. The slightly greater increment would be likely to make the final tooth thinner, and it is possible that the compiler read a 6 as a Zero.

There appear to be other errors, possibly merely typos. Has anyone else had similar problems?

Howard

Correct, for a 90:1 reduction and 13 divisions you require 6 and 36/39 turns per tooth.

Andrew

Thanks!

So, despite my misgivings, the Vertex manual does contain some errors, (found others as well) and my spreadsheet looks to be correct! Ah well off to turn up another gear blank to Loctite into place, ready for turning and gearcutting.

One day, I will get this job finished.

Howard

My Vertex dividing head chart (ratio 1:40) has a an error for 24t ,obviously a typo as it states 1 turn and 33/22 of a turn on a 33 hole dividing plate. You are going to spot the error though as it is impossible to do that. However, I no longer trust the printed charts without confirming the sums. Colin

After finding one error in the chart for the HV6 I went through the lot. Seem to remember there were a good few cockups so do check first!

Paul

It would be a service and help someone else if the faults could be reported to the makers. As long as the makers then made the corrections, of course. Has anyone had experience of Vertex in this regard?

Cheers, Tim

Is it possible for someone to post/print a set of new figures for us not so bright ones that find it difficult to do the maths ?.

The arithmetic for dividing heads is to take the number of turns to do 360 degrees (40) or (90) Divide by the divisions required keep answer in fractions. For 13 divisions this would be:-

90/13 = 6 12/13

Multiple the denominator 13 by a number that gives a set of holes on a division plate you have and multiply the numerator 12 by the same number.

For the above example the 13*3=39 and 12x3=36

Therefore 6 turns. 36 holes on 39 hole plate

For 40 turn head 40/13 = 3 1/13 if you have 26 hole plate the

13*2 =26 1*2=2 therefore 3 turns 2 holes on 26 hole plate

Use 3 for 39 hole plate which works 13*3=39 and 1*3=3

Which = 3 turns and 3 holes on 39 hole plate.

Tom

If someone can compile a corrected chart as a PDF, I'll happily put it up on this site.

Neil

Have E mailed my revised chart, as a WORD document, to Neil, in the hope that he can transpose it in to a PDF.

The Print out will be laminated for use in the workshop, and an additional copy kept in the folder with the Vertex manual.

My Spreadsheet for all the calcs, running to four worksheets, (One basic, and then one for each of the three Division Plates) is on EXCEL. Most of the results co-incide with the Vertex chart, but NOT ALL. It looks as if some errors are typos, and others, like the 13 Divisions one, of misreading handwritten figures (30 instead and 36 in this case)

If anyone wants this, it is for a 90:1, but can easily be amended for different ratios, (but check a few results against known "good" results, to be sure), send me a PM with an E mail address, and I'll forward it, (Its only 64Kb).

Unless Neil wants to put it on here?

Howard

If only this site could host other file formats than jpg then this could be posted as a working spreadsheet, with an option to change the worm wheel count. How about it Neil?

By the way Howard, recent versions of Word have an option to "Save As" PDF.

Howard's table is HERE

Thanks Howard,

Neil

.

Thank you both

MichaelG.

Thank you gentlemen for the rapid response , I have printed it and will get my daughter to laminate it . Ken.

Hello All, Good evening.

Are the hole counts for the plates supplied with a 40 tooth worm wheel conventionally the same as those shown for plates A,B,C in Howard's PDF?

I've got a BS0 head but it has a 40T wheel. The numbers of holes in the three plates that came with it happen to coincide with the A B and C plates Howard uses - is this accident or design?

Thanks in anticipation

Best rgds Simon

Accident, I think - I remember reading that one of the popular dividing heads was supplied with a set of plates with hole numbers better suited to a different ratio.

Neil

Regardless of the worm ratio what you need is prime numbers or multiple of primes working up from the bottom so the only differences tend to be which multiples you get. Some sets go for higher multiples if the plate is big enough to have room or mix them in a different way on the plates.
After the 3 in the table many suppliers also then did additional plates with primes working up from 51, 53, 57 etc

BTW while on the subject of errors the Victoria tables for differential indexing have a few errors so if you are using them to cut 201 and above call me - I think some gears have never ever been cut. Who wants 233 or 269 anyway?

Edited By Bazyle on 24/02/2016 21:50:15

The spreadsheet was made up for the Vertex HV6 which has a 90:1 ratio, but presumably, copying the spreadsheet, and substituting another ratio for the "90" in the formula, would produce a set of results for a R T or D H with that particular ratio.

Today, using the figures from the spreadsheet, I have produced a fairly good looking 13T gear, so one calculation seems to be right!

Howard

Just come across a website with a spreadsheet that can easily be used for any plates and any division. It uses a novel but simple way of presenting the info to show the multiple options. Choose the 'Threads......' download and the dividing tab .

It is just Excel so you can fiddle with it. It shows 270 holes on a 39 hole plate so you can modify it to do the divide by 39 and show the full turns and parts.

off top-ic he also has a gear ratio calculator but it assumes you have ALL the gears from 20 to 100.

Edited By Bazyle on 27/02/2016 12:55:14

Printed off the pdf but unfortunately, it still contains the same error for 13 divisions - i.e. 6 Turns + 30/39 and not 6 turns + 36/39.

The other two errors I am aware of on the original Vertex instructions for 7 divisions and 40 divisions are corrected on the pdf.

Regards

John Shepherd

Edited By John Shepherd on 27/02/2016 16:55:50