Gear Train Calculator

[CalumParticipant @calumgalleitch87969]

Many of you will have seen this in the Lathe gear calculation thread, but as I've now started to adapt it for my own and perhaps other's use I thought it might be useful to give it its own thread.

My aim is to produce a simple, one page webpage that can be used to calculate arbitrary gear trains for a lathe with two compound stages. Features I have added are

• Ability to set an input ratio (where the incoming drive from the spindle has already been ratioed down, and/or fixed wheels provide an initial gearing – my lathe does both!)
• Ability to specify the first driving wheel for those with a fixed first wheel, so the user does not have to scan through rows of useless output

To use the webpage, go to **LINK** and you can simply fill in the details and run it on the webpage, or you can also save a copy on your local machine – it requires no other files nor an internet connection, it runs entirely locally.

The next two features I intend to add are the ability to input any available quick change ratios, and the ability to distinguish between trains with acceptable error and trains with no (theoretical) error.

I'm more than happy to add features, etc, if anyone would find it useful. I would be interested to know if there are other common layouts that it would be useful to accommodate.

[CalumParticipant @calumgalleitch87969]

A simple HTML-based calculator

[Hairy PeteParticipant @hairypete39644]

Here's one I made earlier. (8 years ago! where did that go?) It was an exercise in learning about html and javascript. It might provide some inspiration for you:

http://www.zen142641.zen.co.uk/LeadScrew.html

No guarantees – it is what it is. If it works for you, great. If not, ignore it.

[CalumParticipant @calumgalleitch87969]

Thanks Pete, that's very nicely laid out. I might have to steal some of your ideas! Like you, although in theory I know HTML and JavaScript, it's rarely used, so I'm learning as I go and it's a useful project for working these things out.

[SillyOldDufferModerator @sillyoldduffer]

I like it, especially the graphic identifying A,B,C,D on the banjo.

Nit picky suggestions:

If source and warranty are considered important, I suggest a hyperlink or button rather than 'View Source', because the latter is too techie for most. Anyone knowledgeable enough to want to look at the source can crack that on their own, but the Warranty should be as simple to find as possible.

As all up to date engineers are metric (discuss!), I'd prefer a natural metric interface rather than converting to TPI. Perhaps a button that switches between TPI and pitch?

Mildly useful if the table had columns showing actual TPI and pitch as well.

Advanced topic: not all gear combinations will fit on the banjo, and it would be good to highlight potential time-wasters. For example, one of the solutions for 12tpi is 35 80 60 70 which engages two large diameter wheels. To identify misfits the maths would have to compare relative diameters derived from the number of teeth. I think it's possible but could be wrong!

Bugs/Features:

Gear sets containing duplicate gears tabulate duplicate results. Try 20, 25, 25, 30, 35, 40, 45, 50, 55, 60, 63, 65, 70, 75, 80, 85. Duplicate results should be removed from the table.

Take a gold star Calum – nice work.

Dave

PS Gold star for Hairy Pete too.   Is this like buses?  You wait 3 hours in the rain and then 3 turn up together!

Edited By SillyOldDuffer on 19/07/2021 14:08:06

[Roderick JenkinsParticipant @roderickjenkins93242]

Calum,

I applaud your effort, particular the fact that your program is completely stand alone and platform independent. I would caution against trying to make your program too universal. My own attempt written in visual basic in Excel is specifically focused on my own particular needs to calculate long leads on a Myford S7 with add on gear box, metric conversion set and loads of change gears. Too specialised, I suggest.

My advice would be to add another pair of gears like Hairy Pete has since most lathes can accommodate this. The option to select 4 or 6 gear trains would be good but clearly six gears gives a better chance of a closer result to the desired pitch so if a 4 gear train won't get close enough then a six gear train is worth a try. I suspect specifying the order of the gears is going to be too difficult since there are so many variations in banjo size and configuration. Letting the user know which are the drivers and which are driven is probably the best you can do. The user can work out which to put where on their own particular lathe. Give the user some options with a list of results since lesser accuracy may be acceptable if the better result won't mesh. I hope these thought are some use.

Regards,

Rod

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