Minnie 1"

The wooden plugs are only to fill the holes so you can mark out the ends. Post a photo of your casting and I'll suggest a way forward as you will have to bore it out from scratch.

Edited By JasonB on 29/03/2020 20:33:47

Will get back to you tomorrow.

I think I would start by lightly filing the top end to give a flat surface for marking out on, swing 4 arcs of approx half the diameter in from points around the edge and then place a punch mark where the middle is likely to be much like whats shown in this image

Now holding the casting by the flange in the 4 jaw chuck get the bottom and top punch mark to run as true as possible then at a slow speed drill with a ctr drill. Bring up the tailstock for support and turn the top parallel section to 1 1/16" and lightly face the end as far in as you can reach without hitting the tailstock ctr.

Reverse the casting around and now gripping by the top parallel section ctr drill the bottom end and again bring up the tailstock ctr for support. Face the end and then the outside of the flange followed by the 31/32" collar. Then taper turn the outside.

Remove the tailstock and fit the fixed steady to run on the 31/32" diameter to support the casting while you drill it out to 3/4".

Reverse the work once more so you are holding by the OD of the flange and set the fixed steady to run on the 1 1/16" top section. You can now bore out the inside to the correct taper.

Thanks very much Jason,I'm half way through.so far so good.for the outside taper do I match the castings existing taper,or do I work it out from the drawings?

Thanks again

James

I'd work it out from the drawings and then see how that compared to the casting and adjust if you need to.

ok, thanks jason, that went pretty well.There is a couple of small holes in the casting i found whilst machining but otherwise all good.

A quick question about hss endmill/slot drill speeds.I seem to be ok with the larger and medium side of end mills/slot drills, but small end mills tend to be a bit hit and miss.i.e. the 1/16" slot drill i just broke.i wonder if im not running them fast enough rpm wise.I always slow down the feed rate on the table feed motor and keep to light cuts. i am running the 1/16" slot drill at about 1100 rpm. I seem to fair slightly better with the 4 fluted type, but tiny diameter anything tends to be a bit hit and miss for me .All machining cutting fluid is used.

Any thoughts anyone?

thanks

james

You don't say what material but that is too slow, Ideally in steel you would want about 6000rpm and aluminium anything upto 12000rpm but will probably have to be limited by the max speed of your machine.I'd hand fees on the small sizes so you get a bit of feel. Depth of cut with those small slot drills one quarter of diameter.

Thanks for the assistance on milling speeds, yeah i was running too slow. ive since solved that issue by doubling the speed and taking smaller cuts.

Quick question.I need to create the reamed hole 1/4" in the axle fork. i have a new hand reamer 1/4".What size would you drill under sized before reaming with the reamer? also can i put the hand reamer in the drill chuck as it has a parallel shank., and do it under power?

thanks

james

15/64th or 6mm would be OK

Yes you can use hand reamers under power but run quite slowly say 200rpm or less.

Hi chaps!

I am fast approaching the front wheels.I have not done the rear wheel first so I have no experience on the process.

What wood would you suggest for creating the jig?and what type of tool to use?

Any tips on turning the ally cast rims?

Next job ATM is milling the spoke recesses in the front wheel hubs.

I've made a jig for the rotary table to keep the alignment .One end spigot for the hole in table,and one for the undersized hole in the hub.

Thanks

James

This seems to be for general questions about a minnie build, so perhaps here.

O-rings.... something of a black art it seems. I have looked up the ztubal Cakn book and I am only a tiny bit less in the dark.

LC Mason speaks of d-bit sizes, and that various supplies of rings vary a little in size, but several times through the book looking and I dont seem to be successful in finding what size rings are required It would be nice to know, in case what I buy are not the same as he originally used

Michael dow nunda

Same applies to cylinder mounting studs: I cant find dimensions, although there is mention of:

a) drill and tap 1/4 depth into cylinder block

b) hex nut depth plus a few threads showing

c) the two chests finish to 5/16" and 3/8" thick

d) both chest covers 3/32 thick

e) 7BA nuts 3/32 thick

giving 3/4 and 13/16 plus say 2 threads showing = 1/32 more,

or calculated lengths of 25/32 and 27/32

Do they sound right? Be nice to see it verified in the text or drawings somewhere, but I couldn't find it

Michael dow nunda

O Rings 1 x bs111, 1 x bs006, 1 x bs010, 1 x bs007 and 1 x Ref B (3/32" ID) nitrile.Plus two to suit your gauge glass.

Make the holes the size Mason gives

As for studs I've never seen their lengths given that is down to the builder to establish. For example it may say drill 1/4" deep but depending on your individual taps the thread will not go right to the bottom of the hole so best do a test of the first one in each group and work it out from there

Well, (as frequently the case, it seems). Jason rides to the rescue. Thanks Jason.

I find Numbers BS006, 007, 010, and 111 without too much bother but what is a reference B?

Michael

0.064" section, 3/32ID, 7/32" OD Viton according to Blackgates but expect you will have to source something locally, no BS number given

Hi all

Im stil going!

Front end done.

Front wheels done

Rear wheels almost done.

Boiler parts all formed and sent off to western steam to be brazed up. [i chickened out of doing it myself]

But im having an issue with the rear wheels rear hub castings. More on that in a minute. Time for some progress photos.