Jig constructed chassis

[relaxinghobby]

I can't remember from whom I bought this chassis jig and I've had it so long the instructions have had time to dissappear. Although I've had it for a while, this is the first time I've tried using it.

After the first attempt I could not get the front wheel bearings to line up, and after several goes at re-soldering them I have de-soldered the lot to start again.

The chassis kit is a nickel silver one from Mainly Trains sold as an upgrade for the Bachmann J72, I have converted it to a 2-4-0 from the intended 0-6-0 configuration as it has the correct 7 foot coupled wheel base for my Isle of Wight tank engine build.

 

Lumpy solder.

 

What's the angle for? Bits lying loosely on jig.

[brossard]

The angle could be a fence used to ensure that both frames are lined up before soldering the spacers. It's not obvious from the picture how the "fence" is attached though. At least my Avonside jig has a fence for that purpose. It is useful for chassis that are compensated or sprung. Not so much, I guess, for a rigid chassis.

 

John

[Gordon A]

From the second picture the right hand tapered end does not appear centered in the coupling rod hole.

This suggests that the jig is not set to the correct wheel base??

 

Suggest you fully strip the chassis sides down, remove wheel bearings and desolder.

 

Next is to check the following:

 

Place one of said sides on top of the other. Do the holes line up?

If only one set of holes line up use these as your reference

 

Place a chassis side on the jig without fitting the wheel bearings.

Do the wholes match the wheel base set on the jig?

 

Place wheel bearings in your reference hole, and fit one side at a time to the jig, and fit second bearing.

 

This may involve a slight enlargement of one or both non reference holes.

 

You need to ensure that the chassis sides are parallel to the jig when this is done.

 

Place both chassis sides on the jig, inner faces towards each other and fit spacers.

 

Gordon A

Bristol

[burgundy]

In addition to the good advice from Gordon A above, can I suggest that you check the upright pins very carefully to ensure that they are absolutely vertical when looked at from all directions. I note that the pin for the third axle is not in place: does this mean that the other two are not glued in position? If so, any misalignment at the end of the pin with the coupling rod on it will be magnified at the frames.

Hope this helps

Best wishes

Eric

[Kenton]

If the frames in the first photo are claimed to have been cleaned up - I suggest you try again. The "lumpy" solder caption implies far too much solder in use and the photo confirms it. There should be no sign of solder on the frames once cleaned then start from there. Never been a great fan of these jigs - probably because I don't have one or feel the need to get one. But I do know that when you give up with any model and start again it must be pulled apart with care to prevent unintended twisting and distortion of the hot metal. It is so easy to impart a very small almost unoticeable twist on a frame or spacer that gets magnified beyond belief when you match up the coupling rods.

 

As always with any engineering the opening of holes to get something to work is usually the last move of a desperate man.

[Guest Natalie Graham]

Is the chassis rigid or does it have sliding hornblocks? If the latter what holds the frames in place while you solder the chassis? I am a bit puzzled as to how the jig is supposed to work.

[Horsetan]

Is this a leftover of a HH jig? Are there bits missing?

[richard_t]

Is this a leftover of a HH jig? Are there bits missing?

 

No the Hobby Holidays one is quite a bit different, the frames are held vertical for a start.

[burgundy]

relaxinghobby

You have a PM

Eric

[relaxinghobby]

Ah thanks for the interest in the chassis jig.

 

I've now assembled the frames for the second time and there are still wonky, the wheels now turn but the frames have come out wonky again but in a whole new direction.

 

I've assembled several 00 etched chassis in the last few years and have always had trouble with them, I've read the Iain Rice book on etched chassis building but he seems to have a natural skill level that I can't reach. The most successful chassis to date has been for the little 2-4-0 Cambrian Railways/G.W.R. tank from Mainly Trains for the Gem white metal body. I've built two so far.

 

The temptation with a jig is not to take so much care as I hoped that the jig would make up for my lack of skill, so it's back to a hot iron and de-soldering braid for another go.

[gerrynick]

I suggest that you look on Eileen's website, where you can find the instructions for the Avonside jig.........this looks remarkably similar to yours.I would recommend thoroughly de-soldering, then checking the frames for flatness. The instructions are , I believe on Youtube in three parts.

2-4-0's and 0-4-2's are far easier than 0-6-0's !!

 

gerrynick

[Kenton]

Once you have cleaned up the frames and spacers thoroughly - and I really mean thoroughly desolder braid alone is not enough. Then place the frames together and on a glass/mirror. There should be no sign of twisting or unevenness and the axle holes should match perfectly. I still have no faith in jigs but it seems the one you have might be incomplete which makes it worse as you are placing faith in something that does not justify it.

[jwealleans]

Definitely not the HH jig which holds the chassis in an upright (i.e. Normal) position.

 

My HH jig is a cracking tool and I wouldn't now be without it.

[relaxinghobby]

Chassis assembled 2nd attempt and still wonky.

 

 

 

 

The frame sides look level but when some 1/8 th inch drills are placed in the axle bushes you can see that they are nowhere near parallel.

At least I can test the footplate for clearance over the wheels.

[relaxinghobby]

Thanks for all the offers of advice and Burgundy recognised the make of chassis jig as the one from E.B. models and sent me a copy of the instructions.

 

I heated up the chassis and pulled it apart and cleaned off the soldered with de-soldering braid.

 

 

I found these temporary frame spacers, I had forgotten about them, I think they come from Comet.

The chassis is a rigid one with the bearings fixed to the frames.

All parts in the picture are not yet soldered, the wood is to hold up the spacers relative to the side frames.

With these it is much easier to get the frames parallel in the vertical plane and level if soldered up on a piece of mirror. But I some how managed to get one side slightly in advance of the other, the wheels spin freely but are a tiny angle from being a right angle to the frames so the chassis veers off sideways if you whiz it along a smooth floor. At least with the both types of jigs I manage to get the axles wrong by exactly the same amount.

 

Part of the problem is I am using cut down parts and they are slightly dissimilar.

 

Third time not so lucky yet

 

I must de solder, clean them up and try again.

[brossard]

I think my advice is to strip it all down again, sit back and let the experts guide you. I recommend two sources:

 

1: This DVD from BRM hosted by Tony Wright: http://www.model-railway-dvd.co.uk/right_track1.php

2: This book by Iain Rice: http://britishrailwaybooks.co.uk/books/ISBN/1874103100.php

 

I followed the Rice instructions and advice (in particular an L shaped wooden jig) for my first chassis (it was compensated) and it worked first time. Yes, it's dated, but Rice has an engaging style and the book contains lots of good info.

 

John

[relaxinghobby]

Is this my 4th or 5th attempt? I'm loosing count. The last time it was nearly there the wheels spun freely but the chassis rocked when placed

on the mirror showing that it was not quiet flat.

 

Here is the next try it's all on a mirror to keep it flat, the big brass spacers from Comet keep the frames apart and vertical, the 1/8th steel

rod helps keep the bearings and chassis holes in a line at right angles to the frame, the squared paper acts as a reference, the wood pieces

hold the spacers up.

 

 

I've watched the Tony Wright video, he uses a type of chassis jig that is no longer available and Iain Rices book is on my shelves, both

these modellers make it seem very easy, I can't seem to emulate them.

[brossard]

Actually there is one jig described in Rice's book that you can make yourself, I alluded to it above. It will keep the chassis square and can be used in conjunction with the Comet jig:

 

 

Mine is pretty tatty and has been used a lot. The MDF used to be flat but has been attacked by flux and should be replaced.

 

Edit: I just reviewed the Tony Wright video. Yes, he makes it look easy, it isn't - at least not for me. His jig is a Jamieson device which is not a lot different in principle to the Comet jig. I also looked at my Comet jig. The threaded rods measure to be 0.117" dia. Your axle holes are 1/8" or 0.125" dia. This tells me that you can't rely on the Comet jig to square the chassis. You have done the right thing by replacing one of the jig units with an axle or 1/8" rod. The other thing is to pick a reference end and use a jig similar to the one pictured to ensure that the frames are square. Pre solder a spacer to one frame and another spacer to the other frame.

 

Keep at it, it will come.

 

John

[Kenton]

Here is the next try it's all on a mirror to keep it flat, the big brass spacers from Comet keep the frames apart and vertical, the 1/8th steel

rod helps keep the bearings and chassis holes in a line at right angles to the frame, the squared paper acts as a reference, the wood pieces

hold the spacers up.

 

Either there is distortion in the photo or I see that set of frames as not being aligned. The point of a mirror is a test for all wheels on the glass - it has little use until that stage has been reached. I am still a little concerned over procedure. The first step I make in chassis construction is to solder the bearings into the frames without spacers. I do this with some force applied to the bearings and having made sure that they fit tight and fully seated in their holes. As always very little solder is used as I don't want lumps of solder upsetting the fit. If each frame is flat and each hole is in the correct place (I have checked that the two frames match perfectly) then nothing can go wrong at this stage. The next step is to solder one folded spacer to each frame - not both to one frame. The final step is to bring the two frames together using a jig or the long rods and using a block with an end stop to keep the frames parallel. A slight jiggle of the rods using the fine 1mm spaced graph paper to align should be all that is required before soldering the opposite spacers in place.

 

Again the spacers should have the minimum of solder. In your photo there looks to be solder swimming all over them and the frames. When you disassemble and clean up the frames and spacers they should be taken back to the clean metal.

 

Biggest cause of out of alignment frames:

1. poor filing off the etch tags and etching cusps on the spacers - if the spacers are not true then there is no hope. Great care and some spacers are sadly not well designed.

2. Opening out the holes in the frames with a file making them oval and too big for the bearings.

3. Far too much solder, the soldered joins should all be metal on metal with a few molecules of solder between not a thick solder sandwich.

4. Allowing parts to move while you are soldering them together. This I guess is where a jig wins as it should hold everything in place.

[MJI]

I think the best answer is to get the chassis square and not worry about the axle boxes

 

Then simple compensation.

 

Rear axle firmly fixed

 

2 axles with slight up down movement.

 

bar across the 2, with pivot in middle.

 

I started making my own years ago for an Airfix 4MT 260, but the motion stuffed me, however pushed along no problem at all.

 

No jigs, just used the coupling rods (home made as well).

 

Never finished as the valve gear was too complex and the body not that great.

[Paul Cram]

And they say modelling in P4 with compensated chassis is diificult! I just use the perseverance spacers through the horn cut outts to solder the chassis up and then use their jigs to hold the hornblocks in place with the coupling rods for spacing. Whole job goes together very easily and any minor misalignment is adjusted by the compensation.