Recent content by Misterg

Excellent work! I found this post after seeing a video about this engine in a tug-boat. If anyone wants to hear the hypnotising sound of the original, I'd recommend a watch (the dialogue is in Dutch, but that doesn't really matter - there are subtitles, anyway). I am delighted that somebody...

What an excellent idea. I've been working on a parametric template model in F360 using exactly the same method to generate it. I reckon your 40T gear only needs ~35°of useful rotation to cut an 8mm thick blank with 6mm over-travel, so some of the templates can be truncated a lot.

Yes - it should be possible to truncate the template - I'm trying to get my head around just how much of the template would be needed. Some travel is lost at the start because of interference between the rolling follower and the edge of the template, and some over-travel would be needed for the...

I came up with the same numbers for lead as you (4.95 & 2.47"). I presume you're looking at CF's plans where the shaft is shown as 4.375" between shoulders and the support block is 2.5" long (giving a max of ~1.8" movement). If you look at any pictures of the jig, the shaft is longer than...

I've found another discussion that goes into more detail on cutter choice with an exact(?) calculation which includes the pitch diameter of the cutter: https://www.model-engineer.co.uk/forums/postings.asp?th=109176 Seems the consensus is that the N/Cos^3(a) approximation is 'close enough' in...

Found it, thankyou! :) Here: Login (Please let me know ASAP if it's not the done thing to link to other forums, and I'll edit the message while I still can.) I can follow the logic of your explanation, thanks very much. Trying to calculate it is something else! I see from the spreadsheet, the...

How does one chose which # cutter to use for this technique? I had assumed that it would be the one for the actual tooth count (#8 for 12 T in this case). The other possibility I had in mind was the cutter should match the tooth count of a spur gear the same PCD as the helical (24 x 0.610 =...

I'm only familiar with the technique in theory - I haven't done it (yet). If it's any help to cross-check your numbers, I've calculated the pitch diameter as 0.610" (so your blank diameter sounds about right). The angles look correct (to me). The only missing information is the lead on your...

In that context, I would take it to be a contraction of 'head' (as in SKT HD for 'Socket Head')

No worries! - I spent a little while trying to enhance the image to be able to read it, but it just doesn't work like it does in the movies... :D

Nice. What does the lettering cast into the base say?

Not <$20, but less than $80 or $90 $34.83 Delivered Generates a huge spark (20mm+ in air) and works in my little hit and miss engine (although I did kill one Hall sensor). They also deliver to UK / Europe (it is £28.21 delivered to the UK).

There's a Youtube channel called 'Learning Turning Metal' where a guy called Andrew Whale has documented his builds of a few Stuart Turner engines. He is / was a relative beginner, so makes a few mistakes, but he *tells* you about them (rather than trying to be a pseudo expert). I think it gives...

I doubt that anything needs modifying - this is the exact purpose of "Reference Dimensions" - they appear in brackets on prints (or with the suffix 'REF' depending on drawing standards). I can't speak for all CAD programs, but both Creo and Fusion360 allow them.

I like that a lot! You've just sparked off a whole load of ideas :)