Mike R

managed to muck up the pic attacment - here it is.

This is reminiscent of the iterations I've gone through trying to design the head and cylinder for a uniflow type diesel.
You could very likely reduce the quantity of liner in the head to just the amount below the spark plug hole, only really need ~4 threads worth to give full strength.
Could even think about sneaking in an oring between the liner and head - drawn poorly below only on the plug side with the black lines my suggestion.

Nice shop.  I really like your little horizontal mill!  It would be just the ticket for fluting locomotive connecting and coupling rods, plus a bunch more period correct details on models, without eating up all the space in the shop like most horizontall mills.

Thanks for folowing up Jason, as Mike notes, good to hear he's ok, and wishing him and his family member the best.

Curious if anyone knows if everything is ok with https://modelengineeringwebsite.com/Index.html - David Carpenter?
Been a few weeks since the last website update.

Quote from: gbritnellHow about this Chris. I'm not an electronics guy but someone who is could use an Ardino like they did for the rotary table drive with stepper motor.

On another forum someone made an arduino driven attachment to cut helical gears, but is using a gear hob to do the cutting.



https://www.homemodelenginemachinist.com/threads/vw-beetle-1-4-scale-motor-model.37873/#post-437054

I have found the "disadvantages" of turning off watch history quite manageable.  One little thing that helps is if you do like a video and think you may want to watch it again, just click on the like button.  That puts the video in your "liked videos" list and is that much easier to find again. Apparently it also helps the creators in some way. Really good videos get saved to a playlist, you can create different ones - "live steam", "Model Internal Combustion Engines", "Home casting", etc.
As I said, you remain in control of what is presented to you to a better degree (still not perfect but such is life).

My easy solution, turn off "watch history".  That way you get absolutely no suggested videos when you log in.  Then treat it like a library or the web in general and search for the things you want to see, not the stuff their algorithm is programmed to feed you.  The only retraining required is on your end (how you behave), not theirs!

You will still get a sidebar of suggested videos after watching something, then its up to you to decide if you are going to continue to watch or go back to the shop and build something!

I will need a gear pump if I ever get around to making a multi cylinder diesel so I dropped a few dollars on one of these VW transmission gear pumps that seem popular with the hydraulic RC model crowd.

The first thing to note is that its already pretty small, not quite tiny and model engine sized but getting close.
It would fit in a 45mm cube (just under 2"), its actually only 37mm deep not including the boss for the shaft or the screw heads.
And yet it could probably be shrunk even more for model engines.

made up of 17 individual pieces total including fasteners, washers, gaskets and pins.

The example I received has 16mm diameter gears and they are 5.80mm wide, and if I counted right have 19 teeth.
They ride on 8mm diameter shafts.
The gear centers appear to be set at 14.62mm
The floating bearing blocks are 8.5mm wide. The main housing is 22.9mm wide, the gears and bearing block stack is 22.83mm
The next important observation is that the fits and clearances on this pump are amazingly close for something that was $9 plus shipping.
The gears and shafts are steel, the main housing is an extrusion, the floating bearing supports and end plates are cast aluminum.

A few more details that seem like they are important for this gear pump design.

The gear end faces and shafts appear to be ground to a high finish.
The floating bearing blocks have a channel that runs front to back on each of the bearings surfaces, it looks like it was cast in place and almost completely removed by machining. See picture.  Its placement makes me believe its an oiling groove by design.
The blocks also have a small channel that runs from near the gear mesh point to the shafts - its on the suction side where the gears are moving apart.
The blocks fit in the housing like a piston to cylinder fit or better, sliding fit but no noticeable clearance.
It is evident that the gears have cut their own clearance in the housing.
There is no seal on the input shaft or the inlet port, evidently this particular unit lives in a bath of oil and leakage out is not a concern.  The outlet port has a single o-ring seal.
I think what this examination is telling me is that absolute minimum clearances are a must, even to the point of interference to allow running in.

Timely discussion, I just looked into this here in Ottawa, ON, Canada and there are other considerations that apply so you need to do your homework on your particular city, state/county/province, supplier,  or country. 
In my case, similar to the UK there is a max that you can reasonably /cost effectively feed back to the grid - 10KW (no max time limit).  Over that requires special engineered (read $$$$$) analysis. 
They also pretty much did away with the biggest incentives. Now the best you can do is effectively reduce your total consumption to 0KWh by generating all day and using that credit at night or during low solar generating time.  The biggest catch is that you are still connected to the grid and about half my electricity bill is made up of "delivery" charges that will still be applicable.  So that really stretches out the payback period.
The above scenario is typically called a grid-tie system and has no batteries.  You can add batteries, but as you've already reduced your consumption to 0KWh it doesn't have any payback, just backup power availability (a definite consideration for some locations outside the city).
Also, to Jo's point - some system designs require "squirrel guards" and others don't.  An additional cost and installation effort.

Thanks for showing that Roger, that looks like an excellent event, I am rather jealous that you were able to attend.  I'm a few thousand km's and an ocean away so no so convenient for me.
I especially like the selection of multi cylinder auto and aircraft engines, absolutely jaw dropping stuff.

have a few thoughts:

1.  The ecu may or may not be complex, really depends on what it is being asked to do. For starters we will ignore all things ignition related. If the ECU is limited to fuel control only then its probably the easiest as its only 1 parameter that needs adjusting - more fuel, less or steady.
Inputs can be either complex or simple.  Simple is probably 2 inputs: Throttle position and RPM.  Make a lookup table that says this throttle position = to this desired RPM.  More complicated is taking inputs that represent load and efficiency - manifold pressure, MAF, manifold temperature, EGT, O2, knock. We can eliminate many of those due to size limitations of a model - knock, O2, MAF and MAP would very likely ruin the model geometry (the main reason for  building a model of a specific engine).  That only leaves temperatures (intake and exhaust) - not the greatest for an IC engine but maybe better than nothing. 
Anyways, that was a long preamble to saying that maybe an Arduino type ECU for a model gas turbine can be modified to do what is needed, as long as you are only trying to control fuel quantity, not timing the fuel delivery.
https://github.com/Jehanzeb1973/Ardu_ECU/blob/main/Rev%209-10%20ECU_Manual.md

If its 2 parameters that need to be controlled, it gets more complicated by a huge amount - lets say its fuel as above, and now we add the timing of the fuel (start and stop times). Then we need to add input (crank position sensor(s)) and more timers in the ECU.

2.  I've been designing a diesel pump and injector using some of Rogers ideas with an eye to simplification.  The basis is a combination of helix and wedge control concepts.  Instead of a helix controlling the end of injection, the plunger has a fixed length with a notch which opens a port to end injection - think of it as a very short helix.  The opening of a pressure bypass is determined by a wedge used in the reverse of the convention - more wedge is less fuel, less wedge is more fuel. Injection always starts at the same time, injection ends when the bypass opens (as in a helix control). Wedge is governor controlled (for diesel operation), could be electronically controlled via a servo or even just mechanically coupled to the throttle position (or a bit of both).
This may be a method of delivering fuel at a specific time that isn't ECU based and could be done relatively compactly driven at camshaft speed.  Now 12 little plunger pumps, thats a bit of a thought.  But still a maybe. 


I hear you about why are you (we) doing this - for me its a challenge that I don't get in my day job.  Keeps a few of the grey cells busy and active at least.

Quote from: VixenThe problem I now have is I cannot simply cut and paste the full Google Ai responses due to formatting issues. I may be able to summarise the findings, if there is sufficient interest on the forum ( fuel injection is not a popular flavour with our steam engine brethren).

Please keep the discussion going here.  I'm very interested in fuel injection, mostly just to learn but also I have been researching (and designing) fuel injection for model diesels and while not directly applicable all information on miniaturized fuel injection is welcome.

I've order from this vendor in China before and the cutters were more than acceptable for me in a home shop environment.  (Waltetap store)
Not sure if the link will work, Aliexpress is terrible for breaking links.

https://www.aliexpress.com/item/1005005985179031.html


It'll probably show some ridiculously low price for "new shoppers - Welcome deal",  but even the regular price of ~$10 each is fine - and free shipping of over a certain amount.  Mind you this is me shopping from Canada - US may be different these days...


If you do buy some thread mills, be aware that finding the cutting parameters can be a small challenge - on bigger ones its printed on them, the small ones may not have it or you need a microscope to read it!  Its also difficult to measure directly as they are single flute with 3 teeth so can't just use a micrometer across the cutting edge.


Good luck on the boring operation.


Mike R

Quote from: steamer

Quote from: JasonbLooking good. Does the Tormach do rigid tapping or do you have a tapping head for it? Hopefully it is not a hand tapping job

NOPE!  I can get a tapping head but I don't have a "active" C axis so no rigid tapping.  Tormach is very proud of their tapping head ....so I'll be hand tapping them
https://tormach.com/tts-er20-collet-tap-holder-32021.html

You really should give thread milling a try, it produces a beautiful thread form and the risk of tool breakage and scrapping a part is quite low - once you've learned how to do it.  It is slower than tapping, but the benefits for a high value part are worth it.  I was surprised at the capability - I've thread milled down to M3 x 0.5 on my Tormach 1100 S3 in stainless steel.  Not sure how small you need to go but might be worth experimenting on a test piece.  Overseas carbide thread mills can be had pretty cheap - ~ $15 each for small sizes.