Author Topic: Roy's Little Engine  (Read 25699 times)

Online Jasonb

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Re: Roy's Little Engine
« Reply #30 on: December 09, 2017, 05:11:04 PM »
Must admit I always prefer to bore my flywheels and pullies to fit the crankshaft exactly, boring also will be true rather than reaming a drilled hole that may have wandered.

Graham I thought the Welsh were made of sterner stuff not fair weather engineers, suppose that's it until after easter! I've put a bit more in the reject thread for you to follow.

Just seen you have quite a few posts over on Chester's forum so will have a look tonight.

http://www.chesterhobbystore.com/forum-50-w.asp?p=%3Fforum%3D393180

Online Alyn Foundry

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Re: Roy's Little Engine
« Reply #31 on: December 09, 2017, 05:37:42 PM »
Hi Jason.

My prescription " antifreeze " has really made me " nesh " ( old English dialect for feeling the cold ) these days.

I too, always bore flywheels as you never know what you're going to find in the hub!

Cheers Graham.

Offline Gas_mantle

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Re: Roy's Little Engine
« Reply #32 on: December 09, 2017, 06:05:34 PM »
I'm interested in what you guys say about boring flywheel hubs, at the moment I tend to make small engines so have been drilling and reaming but have wondered about investing in (or making) some small boring bars, the smallest I have at the mo needs a 13mm minimum dia.

Do you still go to the trouble of boring out say 8mm holes ?

Online Alyn Foundry

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Re: Roy's Little Engine
« Reply #33 on: December 09, 2017, 06:32:16 PM »
I'm interested in what you guys say about boring flywheel hubs, at the moment I tend to make small engines so have been drilling and reaming but have wondered about investing in (or making) some small boring bars, the smallest I have at the mo needs a 13mm minimum dia.

Do you still go to the trouble of boring out say 8mm holes ?

Hello Gas_mantle.

Yes, emphatically yes! I have made HSS boring bars that'll do a 3/16" hole ( 4mm )

I also used to bore the displacer spindle hole for the Robinson hot air engine, they were at 5/16" ( 8mm )

There's nothing worse than seeing a wobbly engine flywheel in my opinion.

Cheers Graham.

Online Jasonb

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Re: Roy's Little Engine
« Reply #34 on: December 09, 2017, 06:42:48 PM »
I do if I can get a bar into it which I usually can. A lot depends on the job for example a built up crank or crank arm for say the Muncaster I would tend to drill and ream ( I do my drilling on the mill) but the flywheel I would drill to say 7.0mm then bore. The crank can be loctited into place and final skimmed and as the depth of the hole is shallow there is less chance of drill wandering and it is a consistant material.

As Graham says with castings there may be a void in the hub or an area of harder material that will throw a drill off and a reamer simply follows the drills path so you may get a suitably sized hole but it won't always be straight and any deviation will be magnified by the large dia of the flywheel.

The other thing with reamers is that they produce a specific size hole, if you buy one here it will most likely give you the nominal size to a tollerance of H7 or on odd occasions H8. However if you are using a bit of bar for a straight shaft or a built up crank that may well not be spot on nominal size so you either need a range of under and over reamers or you can just bore to fit, I stop measuring when I get close and just sneak up on the final size by using the finished part of a bit of the same material as a gauge. Also a reamer may also cut a bit larger or smaller depending on material, size of pilot hole, if you let swarf build up or how sharp it is. Some of this you can get round by making the shaft to fit the reamed hole but it still won't help if it is following a wonky drilled hole.

J

Offline Gas_mantle

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Re: Roy's Little Engine
« Reply #35 on: December 09, 2017, 07:55:16 PM »
Thanks, that's useful info about boring v reaming, I hadn't really thought about boring holes that are the same size as one my reamers. Till now I've got the boring bars out to make large dia holes and ream smaller ones.

The reamers I have are a beginner / budget set that go from 3mm to 10mm in 1mm steps, they were only about 30 so they aren't great quality and don't always give consistent results.

At the moment the flywheel for my Muncaster engine is a drilled and reamed Lady Stephanie casting, it turned out ok but I'm looking at replacing it with a more decorative curved spoke wheel and it may be time to try the boring out method  :)

Online Jo

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Re: Roy's Little Engine
« Reply #36 on: December 11, 2017, 01:12:12 PM »
Time to cut the keyways in the crank. This is best done before taking the centre out from between the webs as the crankshaft is stiffer. It is easy to make sure both ends are at the same angle by squaring up on the webs, not forgetting to use a wobbler to find the centre of the crank and supporting the end with the tailstock ;). I have chosen to do my slots 3mm as I have a broach that size.

After slotting the centre can be safely cut out from between the webs.

Jo
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Offline b.lindsey

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Re: Roy's Little Engine
« Reply #37 on: December 11, 2017, 01:24:34 PM »
This one is moving right along Jo. This will make a very nice little engine!!

Bill

Online Jo

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Re: Roy's Little Engine
« Reply #38 on: December 11, 2017, 02:15:56 PM »
This will make a very nice little engine!!

Yes, It is a bit of a cutie :embarassed: It will be a lot easier to move around in comparison with those other two big steam engines sitting on the bench in the workshop  ::)

Jo
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Online Jasonb

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Re: Roy's Little Engine
« Reply #39 on: December 11, 2017, 02:30:46 PM »
Looks like some areas of Hampshire are snow bound today :disappointed:

Offline b.lindsey

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Re: Roy's Little Engine
« Reply #40 on: December 11, 2017, 02:38:52 PM »
Jo,

I still have the 'lil brother castings aging under the workbench which also falls into that "cutie" category.  Just waiting on retirement now to get to work on some of these casting kits in waiting. May 31 is the date now  :D Are you still going to beat me ??

Bill

Online Jo

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Re: Roy's Little Engine
« Reply #41 on: December 11, 2017, 02:49:26 PM »
Looks like some areas of Hampshire are snow bound today :disappointed:

They are planning on being ice bound tomorrow  ::)

Just waiting on retirement now to get to work on some of these casting kits in waiting. May 31 is the date now  :D Are you still going to beat me ??

:'( They are mean and are only letting the production guys go and no engineers :stickpoke: To make matters worse it looks like little Sis is going to get a package about the end of May :ShakeHead: I'm the one who wants it :wallbang:

Bill, did I mention the New Holland and the 1/6th Galloway that are also hidden away  :naughty:

Jo
« Last Edit: December 11, 2017, 04:35:59 PM by Jo »
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Online Jasonb

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Re: Roy's Little Engine
« Reply #42 on: December 11, 2017, 03:11:23 PM »

Bill, did I mention the New Holland and the 1/8th Galloway that are also hidden away  :naughty:

Jo

That has shrunk since I sold it to you when it was 1/6th scale, hope you have not been keeping it in a damp cabin hoping for it to develope that special coating you love :LittleDevil:

J

PS best get your skates on for tomorrow

Online Jo

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Re: Roy's Little Engine
« Reply #43 on: December 17, 2017, 02:31:57 PM »
The casting I decided to treat myself with today was the exhaust amplifier muffler :naughty:

The top had to be held on the top of the curved surface to enable the bottom to be turned and have a concave inside turned into it. The bottom has a sticky out bit into which the exhaust goes. this was first cleaned up, then used to turn the remainder of that half including drilling and tapping for the thread.

The two bits were then superglued together and brought to identically the same diameter. while together the three spacing holes were drilled 8BA.

Back to pinning reversing gear  :paranoia:

Jo
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Online Jo

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Re: Roy's Little Engine
« Reply #44 on: December 19, 2017, 02:02:17 PM »
For a bit of light relief I decided to cut a couple of gears. Gears are easy with a dividing head  ;) Machine up your blanks  - here I am using Cast Iron as it is self lubricating.

Find the correct division plate and mount it up. The drawings are no specific about what gears to use the originals being mechanio  :facepalm: so I chose to make mine 40DP 52 tooth and 26 tooth. so that requires a 39 hole dividing plate with a 40:1 worm on the dividing head and 30 holes for the 52 tooth  gear and 1 whole turn plus 21 holes for the 26 tooth wheel.

Having selected the correct gear cutter and centralised it, the cutter is brought in so that it just touches, then backed out along the gear spindle direction, the 1.3mm cut put on then it is time to start cutting  :whoohoo: One must remember to take the cutter fully clear of the gear before you advance the dividing head before the next cut  ::)

It is always nice to watch a gear appearing as if by magic and even better when you don't get half a tooth.

The only question is does it look about right for where the lay shaft will be going  :noidea:

Jo

P.S. The gear blank sizes were calculated using my copy of shopCal
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