Author Topic: Metric Version of W Lindsey's Rotary Beam Engine  (Read 304 times)

Offline bwal

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Metric Version of W Lindsey's Rotary Beam Engine
« on: November 02, 2017, 08:42:40 PM »
Good Morning,

Early this year I received a copy of the Mr Lindsey's Rotary Beam Engine plans.  They are in imperial which I have attempted to convert to metric.  I'm wondering if anyone has a metric version of the plans?  I would like to see how I went.  I did the conversions over a couple of nights and while I'm sure I was consistent I may have rounded up or down on occasion.

I will be using BA and Metric threads instead of imperial as well.

Thanks Ben.

Offline MJM460

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Re: Metric Version of W Lindsey's Rotary Beam Engine
« Reply #1 on: November 02, 2017, 09:44:57 PM »
Hi Ben,

I don't have any version of those plans, looking forward to seeing your build.  I have chosen to go metric with all my tooling.  When I design small parts I often compare with the detail on published plans.  I find that you have to be careful to not only convert dimensions of the metal bits, but also check the remaining clearances between closely spaced holes and so on, sometimes the accumulated differences mean there is no remaining clearance, or perhaps just not enough tolerance for a slight position error. 

So sometimes you have to round down to the nearest tool size, sometimes up, but always check clearances as well as the part size.  The threads you use will make a difference to the overall look, and sometimes metric nuts look a bit oversize on a small model, but I have found this is also apparent if you look at a full size metric machine if you are familiar with looking at imperial threads.  Unless you are trying to make a truly authentic historical machine, you soon get used to seeing the proportions of what you use.

And sometimes you can still only get imperial size materials, so you are faced with just using it, or extra machining to get the size you want.

I have collected a series of 1 mm pitch taps and dies to give me a finer thread option for parts when there are only a few threads.  But I suspect I will eventually end up with a few ME sizes when those 32 or 40 tpi threads are just right for fine adjustments, or to allow connections to some purchased fittings.

MJM460
The more I learn, the more I find that I still have to learn!

Online b.lindsey

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Re: Metric Version of W Lindsey's Rotary Beam Engine
« Reply #2 on: November 02, 2017, 09:51:04 PM »
Ben, to my knowledge, noone has converted these to metric. It should be pretty straightforward, and fasteners shouldn't be too critical so use what fits and looks good. Will be following your progress.

Bill

Offline bwal

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Re: Metric Version of W Lindsey's Rotary Beam Engine
« Reply #3 on: November 02, 2017, 11:22:06 PM »
Hi,

I'll just push on then.

I find that you have to be careful to not only convert dimensions of the metal bits, but also check the remaining clearances between closely spaced holes and so on, sometimes the accumulated differences mean there is no remaining clearance, or perhaps just not enough tolerance for a slight position error. 

That's what I'm more worried about.  I'll probably find a few mistakes I've made in conversion and not allowing enough or too much tolerance along the way.  Only means more shed time!

Thanks anyway.
Ben.

Offline bwal

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Re: Metric Version of W Lindsey's Rotary Beam Engine
« Reply #4 on: November 02, 2017, 11:24:11 PM »
PS,  when I say converted I mean I did the sums on my phone at night whilst listening to my wife watching tv and wrote it all down next to the imperial figures on the drawings.