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Minnie 1"

Beginner minnie 1" build

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JasonB06/06/2019 17:15:28
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Not quite Rod.

Common practice now to use copper rivits instead of threaded stays and nuts.

The 5 fixings for the hornplates go into solid bronze stays about 3/8" diameter that are machined true to the barrel after the boiler is complete and then the hornplates are offered up, set to the correct position and the holes spotted through.

As with anything boiler related talk any changes from the drawings through with your boiler inspector first

james huxstep15/06/2019 14:42:43
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So all good so far, I have 2 firebox plates, smoke box, boiler barrel to size and shape and have done the throat plate. Some 3/32 copper rivets have arrived 1/2" and 3/8" long with two rivet snaps. The hole in which the rivet shank goes into does not bottom out. Is this normal or is the hole too deep. I haven't given the riveting a practice yet but my understanding is this.

Drill hole in both parts to be riveted together

Place rivet through both plates factory head down and lying in the concaved part of the set tool held in a vice.

Get the other tool and place the upturned rivet shank into the hole(not bottoming out/bottoming out?)

Give it a tap

Use other concave part to tap down and form head, but not too tight to allow solder to flow.

Sound good?

Also if I can't get my riveting skills up to scratch, what is to stop me just putting appropriate sized copper bag screws and nuts in and soldering them in and filing flush? Or is it a case of honing my skills with the rivets.

Thanks

James

JasonB15/06/2019 14:50:22
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You want the hole deep as it is the plates you are setting together, you are not expanding the rivit.

All sounds OK

get the practice in now where it does not really show

james huxstep26/07/2019 14:09:50
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OK first dry assembly done, all good nice and square and level.

1/going to turn the phos bronze bushes for back head. Want to make a hss tool for this job any suggestions on tool/turning phos bronze?

2/turning /milling copper cutting fluid or not?

Pictures to follow

Ron Olmstead03/08/2019 06:29:30
4 forum posts

Following, got the drawings and book. Contemplating starting my own minnie.

james huxstep10/03/2020 14:06:14
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74 forum posts
11 photos

ok so......

Ive started on the front assembly, smokebox etc while i get brave enough to solder the boiler together.So far so good smokebox/ring/door chimney casting done and fitted and divided for the 1/16" rivets. Onto the steel section at bottom of smokebox which holds the front axle fork. Achieved a nice radius in the 1/16" steel to match smokebox od for the base of the box section under the smokebox. Onto the box section itself, made a nice radiused former to bend sheet mild steel over [compensated in width to bring the final width once formed to the 1" required]. Achieved a nice 90 degree bend in the sheet mild steel but not at the radius i filed, not far off but if i continued it would have made the component drastitically overwidth.

Is this the minimum bend radius for 1/16" plate?

Do i anneal the steel sheet? [ [i know this is not as easy to do as sheet copper or brass]

Do i measure radius formed with a radius gauge and edit the former accordingly?

thanks

james

ps i have photos of progress if anyone is interested.

Harry Wilkes10/03/2020 14:35:54
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Posted by james huxstep on 10/03/2020 14:06:14:

ok so......

Ive started on the front assembly, smokebox etc while i get brave enough to solder the boiler together.So far so good smokebox/ring/door chimney casting done and fitted and divided for the 1/16" rivets. Onto the steel section at bottom of smokebox which holds the front axle fork. Achieved a nice radius in the 1/16" steel to match smokebox od for the base of the box section under the smokebox. Onto the box section itself, made a nice radiused former to bend sheet mild steel over [compensated in width to bring the final width once formed to the 1" required]. Achieved a nice 90 degree bend in the sheet mild steel but not at the radius i filed, not far off but if i continued it would have made the component drastitically overwidth.

Is this the minimum bend radius for 1/16" plate?

Do i anneal the steel sheet? [ [i know this is not as easy to do as sheet copper or brass]

Do i measure radius formed with a radius gauge and edit the former accordingly?

thanks

james

ps i have photos of progress if anyone is interested.

Pop them in an album we can all take a look 👍. i/m maybe a bit premature but if you have not I'd do some research on the fitting and placment of the water pump.

H

james huxstep10/03/2020 15:08:03
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74 forum posts
11 photos

OK will do.

I have machined the pump pad, but that is as much as I have done on that.

Thanks

James

Brian Abbott10/03/2020 15:15:38
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448 forum posts
82 photos

Hi James.

I have taken loads of photos whilst building my Minnie, just shout if you need anything.

james huxstep10/03/2020 15:33:40
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74 forum posts
11 photos

Hi thanks.

So what would you suggest for the axle fork box under the smokebox? Edit the radius for bigger on the former accordingly,or anneal the 1/16" steel to try and match the formers existing smaller radius?

Thanks

James

Brian Abbott10/03/2020 15:55:10
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448 forum posts
82 photos

Hi James.

I just bent the 1/16 plate in a vice between two blocks, then soldered to the curved section.

No real point annealing as it doesn't make a great any difference with mild steel.

minnie (346).jpg

Edited By Brian Abbott on 10/03/2020 15:55:30

Edited By Brian Abbott on 10/03/2020 15:55:42

james huxstep10/03/2020 16:31:48
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74 forum posts
11 photos

Very nice!

In the vice between two blocks of steel,or wood?

Thanks

James

Brian Abbott10/03/2020 16:51:30
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448 forum posts
82 photos

Two blocks of steel, just in the vice, I had to overhang the edge of the vice for the second bend.

Just file a radius on the block and tap it round.

james huxstep10/03/2020 18:00:01
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74 forum posts
11 photos

Cheers mate,I'll give that a try. I'll keep you posted

Thanks

James

james huxstep11/03/2020 17:19:14
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74 forum posts
11 photos

Well success!

Talk about making things harder than they need to be.A few encouragements with a rubber hammer using the steel in the vice plan, worked a trick.

Thanks for all your help guys!

james

Brian Abbott11/03/2020 18:23:25
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448 forum posts
82 photos

Sometimes we overthink these things.

Good luck with the build.

james huxstep25/03/2020 18:38:51
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74 forum posts
11 photos

ok, so i have achieved the whole axle box assembly+bush front and back plate and machined the chimney base. Tomorrow im looking at making the two holes under the chimney base casting in the smokebox itself. The 3/4" one and the smaller one to the side for the blower fitting. Now i know from past experience that copper is very grabby. Should i put a centre drill in and then straight to the 3/4" drill, or centre and then a range of drills ramping up to eventually the 3/4" drill.?

thanks

james

pgk pgk25/03/2020 19:21:02
1779 forum posts
287 photos

I needed an accurate hole in the side of a twin gang plastic back-box yesterday. OK not as grabby as copper but i chose to drill a central through hole and then go with an endmill to size.

pgk

JasonB25/03/2020 19:24:11
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18088 forum posts
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I think an ordinary twist drill will end in tears. A step drill will be a lot less likely to snatch or if you have a boring head than that would work well, failing that a 6" half round file won't take long for the larger hole and then the step drill, ctr cutting milling cutter or round file for the blower clearance.

 

Edited By JasonB on 25/03/2020 19:26:15

james huxstep29/03/2020 19:59:54
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74 forum posts
11 photos

OK thanks for the assistance. A set of step drills ordered,so hopefully all will be fine with that.

Any ideas on how to turn the chimney casting? I get all the basic turning bits,its the whole centring it to run concentric with the inner bore. The book suggests making plugs for either end but my ally casting does not have any holes in either end.

Also how's best to turn aluminum?

Thanks

James

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