Building a 31/2" Gauge Locomotive Engine

Gallery, Projects and General > Project Logs

<< < (14/67) > >>

sbwhart:
Hi Ralph

You can pop round tomorrow and see the progress so far if you've got time.

where did this come from :nrocks:

Like it

:D

Stew

sbwhart:
Choo Choo I'm back on the Loco Project

:D :) :D :) :D :)

:nrocks: :ddb: :nrocks: :ddb: :nrocks:

First job finish of the eccentric straps by fixing the arms to the straps

The important feature with the assembly is that you get the hole centres on all four exactly the same to do this you have to make an assembly jig.

So first job a crib sheet and crap O cad of the jig.

I'm going to use a chunk of ally that I picked up from the scrapy that I've used a number of times for bits of jigs and fixtures so its got a few holes in it already but I can work round these, and a piece of the bar left over when I made the eccentrics and put aside for this job, its a nice fit on the straps.

The chunk of ally was squared up with a flycutter

At a suitable distance from one end a 5mm drill was put right through then a 9.5mm drill 10mm deep followed by a 10mm drill, then using the hand wheel dials the table was moved the exact hole centre distance (58.74mm) a 3mm hole was drilled 10mm deep followed by a 1/8 drill.

The piece of bar was chucked up true in the lathe and and a short length turned down to 10mm a nice fit in the ally, it was also drilled and tapped through M5 and parted of to a suitable length sorry no pics of this.

Some big washers were modified as clamps and that was the jig done.

The eccentric straps are riveted to the arms so the first job was to mark out the position for the holes and drill 1/16 I,m drilling the holes before doing the slots because I'll have more thickness of metel, to drill after they are slotted could result in them bending. To hold the straps for drilling and slotting I used the assembly jig.

Setting the strap square in the jig

Drilling the 1/16 hole

Finding the

Finding the edge of the slot with fag paper:- DRO zeroed and head lowered by half the total thickness of the cutter and the strap to bring the cutter on centre.

Milling the slot with a 2mm slitting saw

And thats the straps finished.

Next job was to rough out the arms, I decided to do all four arms together I cut out some steel strip and stuck them together with two way sticky tape to make a pack. The pack wa squared up and a 3mm hole drilled through one end and a 3mm dowel loctited in place to keep everything together.

Then by twidleing the handles the straps wer roughed out

Well thats the lot for tonight next job will be silver soldering a block onto the arms so that a fork can be milled into the ends

Have Fun

Stew

Divided he ad:
Nice workings there Stew :dremel:

I've never had to make such before but may do one day?

The holding jig is a thing worth remembering, that's the kind of stuff that comes in usefull all over the place :thumbup:

Glad your back on the job too :whip: :headbang:

Ralph.

SPiN Racing:
Very Cool...

For Loco Noobs like me its going to be interesting reading. Watching the loco threads.... :nrocks:

sbwhart:
Had a bit of shop time this afternoon so decided to silver solder eccentric arms for the fork.

I seem to have accumulated quite a few way to heat things up.

On the left in the red tank is Propane torch I've had this set up for about 12 months and not used it yet, I got it to solder the loco boiler together

Next to this is a small welding system its not an acetaline system, its supposed to be similar, I bought it to braze the frame of my loco but I just couldn't get enough heat into the metal so ended up riveting it together.

Next is a Plumbers butane soldering torch this work well for silver soldering but the blast is a bit fears, it can blow light items about a bit.

At the front is a small pencil torch you charge up with lighter gas, OK for realy small soft soldering bits.

For this job I'm going to use the new propane torch.

First a bit of safety.

You need to be carful with gas cylinders make sure your using the correct regulators etc.
Make sure you havn't any other cylinders, airosols, and combustable items about where your doing the job.
Wear safety glasses in case you gat a splash. Wear Leather gloves.
And put a bend on the end of the solder rod to let you know which is the end to pick it up buy, the other end will be hot.

This is my hearth made up from fire bricks.

Preparation of the work piece is important you need to get the faces cleaned back to bare metal and silver solder works by capillary action so I've put four nice deep centre pops on one of the mating faces so that a small gap is formed for the solder to flow into, I,m using easy flow flux and easy flow 55 silver solder. I've also got some pliers and tweezers and a piece of wire to lift, move and poke the hot bits

A liberal dose of flux was dolloped between the bits and a small length solder placed on the joint.

The torch was fired up and the flame directed on the thick end of the work away from the solder, the solder will flow towards the heat when it melts, you have to be carful thing don't move, if they do tease them back in place with the wire, you can add a bit more solder by holding the rod on the work if you think it needs it, keep the flame on to get a nice uniform heat to let the solder flow, not too long or you can spoil the solder, let the job cool down for a few minutes then you can quench it in water.

This is the result you can see where the solder is showing all around the edge of the work.

I've been having seconds thoughts :scratch: about making these arms this way it may have been better to have milled them from solid :scratch: I've got this far so I'll see how it goes.

Stew

Navigation

 Message Index

Go to full version