connecting rods
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chainsaw18648
- GNR J52 0-6-0T
- Posts: 24
- Joined: Fri Sep 26, 2008 11:22 am
connecting rods
Hi I have'nt been on for some time due my love affair with a cock of the north kit rescue which I bought on ebay.Only it was'nt a kit it was a rather nice japanese brass model of 1970's vintage that some one had mistakenly tried to motorise.Sooooo!!!.I have got hold of a book entitled the 4mm locomotive and have managed to build for the body a decent chassis (piccys will come later together with how to instructions) but I have a very slight sticking point on the con rods just enough to cheese me off has any body got any cures or way of diagnosing which hole is out best wishes mick
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Colombo
- LNER Thompson B1 4-6-0 'Antelope'
- Posts: 657
- Joined: Mon Oct 03, 2005 4:44 pm
- Location: Derbyshire
- Contact:
Re: connecting rods
As one who has been there and had to overcome ther problem several times, I shall try to explain what I would do, in anticipation of a problem if I don't.
1. To start with I would use Romford or Markit driving wheels as these are self quartering. If you have not got Romfords/Markits them you have to have a quartering jig, or failing that you are reduced to lining up the spokes. It is important that the crankpins are correctly fitted.
2. Make or buy the correct coupling rods first of all, ensuring that they are identical and straight by pinning them onto a jig.
3. Use the coupling rods to line up the pilot drill for the axle holes in the frames and then drill ever so slightly oversize for the bearings.
4. Presumably you are using brass bearings. I use a set of spring loaded extended axles with points on each end made for the purpose. Put the bearings in their holes and fit the coupling rods on the pointy ends. Lightly solder in the bearings.
5. Install the wheels and axles and check on a flat sheet of plate glass such as a mirror that all the wheels touch the glass without wobbling. Adjust as necessary with the extended axles in place.
6. Fit the coupling rods using bits of electrical insulation from a wire as a temporary retainer. If all the above has been done correctly, it should work first time, but it probably won't. Do not despair.
7. Turn the coupling rods upside down and fit them to the pair of axles at one end of the chassis. This will reveal any problems at that end. Elongate the crankpin holes but do not enlarge them.
8. Repeat at the other end. When you have got the two sets of four wheels turning without any sticking points, you can try the rods in their correct position.
That is what I would do. If you have not followed the above procedure, the best I can suggest is that you start at line 7.
Best of luck!
Colombo
Colombo
1. To start with I would use Romford or Markit driving wheels as these are self quartering. If you have not got Romfords/Markits them you have to have a quartering jig, or failing that you are reduced to lining up the spokes. It is important that the crankpins are correctly fitted.
2. Make or buy the correct coupling rods first of all, ensuring that they are identical and straight by pinning them onto a jig.
3. Use the coupling rods to line up the pilot drill for the axle holes in the frames and then drill ever so slightly oversize for the bearings.
4. Presumably you are using brass bearings. I use a set of spring loaded extended axles with points on each end made for the purpose. Put the bearings in their holes and fit the coupling rods on the pointy ends. Lightly solder in the bearings.
5. Install the wheels and axles and check on a flat sheet of plate glass such as a mirror that all the wheels touch the glass without wobbling. Adjust as necessary with the extended axles in place.
6. Fit the coupling rods using bits of electrical insulation from a wire as a temporary retainer. If all the above has been done correctly, it should work first time, but it probably won't. Do not despair.
7. Turn the coupling rods upside down and fit them to the pair of axles at one end of the chassis. This will reveal any problems at that end. Elongate the crankpin holes but do not enlarge them.
8. Repeat at the other end. When you have got the two sets of four wheels turning without any sticking points, you can try the rods in their correct position.
That is what I would do. If you have not followed the above procedure, the best I can suggest is that you start at line 7.
Best of luck!
Colombo
Colombo
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chainsaw18648
- GNR J52 0-6-0T
- Posts: 24
- Joined: Fri Sep 26, 2008 11:22 am
Re: connecting rods
Hi thanks for the info I shall endeavour,but I suspect it will mean another set of con rods filed with my own little hands .I am however fascinated by the spring loaded axles were they a home remedy or can one purcase such lovely little things.bestwishes mick. 
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Colombo
- LNER Thompson B1 4-6-0 'Antelope'
- Posts: 657
- Joined: Mon Oct 03, 2005 4:44 pm
- Location: Derbyshire
- Contact:
Re: connecting rods
Mick,
I bought my set of hornblock alignment jigs a very long time ago: they were made by Perseverance (the company that is, not my personal efforts). I have just Googled "Hornblock Alignment Jig" and found that they are supplied by a number of companies. Markits do list them on their PDF catalogue as MRALJ and there is a picture of them.
You can use them for aligning sliding hornblocks for a sprung or compensated chassis as well as for soldering top hat bearings for a rigid chassis (provided you ensure that the axles are all in the same horizontal plain).
Alan Gibson used to supply a set of universal coupling rods for a 6 coupled wheelbase.
Colombo
I bought my set of hornblock alignment jigs a very long time ago: they were made by Perseverance (the company that is, not my personal efforts). I have just Googled "Hornblock Alignment Jig" and found that they are supplied by a number of companies. Markits do list them on their PDF catalogue as MRALJ and there is a picture of them.
You can use them for aligning sliding hornblocks for a sprung or compensated chassis as well as for soldering top hat bearings for a rigid chassis (provided you ensure that the axles are all in the same horizontal plain).
Alan Gibson used to supply a set of universal coupling rods for a 6 coupled wheelbase.
Colombo