Avonside Chassis Clamps

Lindsay G
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Joined: Thu Aug 07, 2008 2:16 am

Avonside Chassis Clamps

Postby Lindsay G » Thu Dec 19, 2013 12:59 am

I've now used the Avonside Chassis2 on a couple of occasions - not a lot to qualify as being an experienced user! Overall, I find the design and build of a high quality but am a bit perplexed with the use of the clamps.

The clamps don't hold the chassis (or hornblocks) firmly in position so it can be moved inadvertently, and possibly unconsciously, during construction with, at worst, undesirable results, and, at least, time whilst everything is set up afresh. Sufficient pressure can't be applied to keep everything immovably in position as the clamps just distort. But, why are the clamps needed at all? I think I saw something from Will (was it?) saying that he didn't use the clamps but I can't find the thread presently. So, I'm possibly not the only one thinking along these lines.

The frames themselves can hold the chassis securely - and I do mean securely - in place. The only aspect that is not catered for in this scenario is that nothing holds the hornblock in place (giving the hands-free aspect otherwise afforded by the jig). However, having got a hornblock into place, it can be held with one hand whilst the other does the business with flux, solder, and iron.

So, I'm forming the opinion that the clamps are a bit of over-engineering (and suspect units into the bargain), and that the jig can be used perfectly well without them.

OR, am I completely overlooking something? What is the verdict of more experienced users?

Lindsay

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Will L
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Re: Avonside Chassis Clamps

Postby Will L » Thu Dec 19, 2013 4:04 pm

Lindsay

I haven't ever use the Avonside jig add on clamps, though I haven't come out and said so before. My approach is to hold the frames parallel to the axle centre line by pressing them against either the top or bottom adjustable bar on the jig which I have carefully set parallel to, and a convenient distance from, the axle centre line. I then use a metal rule, with a nice square end, pressed against one of these bars to keep the horn guide at a true right angle to the frame, like in this picture.
CSB J10 frames 10.jpg


This leaves open a couple of points.
1. How to ensure the horn guides go into the frames at the same place on each side. In the case in the picture this was done by putting a fourth axle pin in the jig to act as end stop, and yes Doug you do have to remember to do the two frame sides the opposite way up. Alternatively, if your using the Highlevel CSB jig you can use it to drill a locating pin hole in the frame over the centre of the middle axle. Putting a pin through that and the corresponding hole in the horn guide will ensure that they go in the same place on both sides. See the Highlevel CSB jig instructions. The other two horn guides will then be accurately located by the axle pins in the Avonside jig.
2. What do you do if neither the top or bottom edge of the frames are parallel to the axle centre line. I'm not sure, it hasn't happened to me yet, but with some of the prototypically profiled frames you get in many kits these days I can see it coming. I suspect I would modify the frames so they effectively do have a parallel edge, it doesn't matter which one,. Others may already have found another way round this one.

The only one of the additional clips and fences I have found a good use for so far is the long vertical fence. This goes on parallel to the axle centre line instead of one of the the top or bottom bars. I use this when putting the frame spacers in. Both frames, complete with horn blocks, are threaded onto long axle pins and butting the parallel side of the frames against this fence should ensure the frames go together nice and square. Experience suggests this isn't a guarantee of absolute perfection, but, just for once, we have one up on the rigid chassis brigade. With a sprung (or compensated) chassis, a slight failure to get the frames sides perfectly flat isn't actually going to cause any bother. Do note that I did say a slight failure, anything naked eye visible is going to affect the performance of the springing.

One other point while we're here. When setting up the Avonside jig from an existing set of coupling rods, I have found that you have to be very careful how you tighten up the set screws which fix the cross bars holding the axle pins into position in the jig. The very act of tightening these screws can push the end of the cross bar to one side or the other, thereby marginally changing the location of the axle pins. So where as the coupling rods should slide on and off the axle pins relatively easily before tightening the set screws they can become a much tighter fit once these screws have been tightened down. If you don't correct this, so the rods are the same easy sliding fit before and after, you will find there is a small mismatch between rods and chassis when your finished. Guess how I found that out.

Will
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David Thorpe

Re: Avonside Chassis Clamps

Postby David Thorpe » Thu Dec 19, 2013 4:17 pm

Will L wrote:Guess how I found that out.


The same way I did? viewtopic.php?f=7&t=1708

The Avonside jig appears to be the one generally favoured on this forum. I wonder if anyone has tried the Hobby Holidays one?

DT

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steamraiser
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Re: Avonside Chassis Clamps

Postby steamraiser » Thu Dec 19, 2013 6:15 pm

I purchased a Happy Holidays jig before the Avonside jig.
I then had the chance of trying an Avonside jig before buying.
I found the Avonside building experience so much easier I placed an order in advance of there general release.
I have not used my HH since receiving the Avonside jig.

Gordon A
Bristol

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Will L
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Re: Avonside Chassis Clamps

Postby Will L » Thu Dec 19, 2013 8:10 pm

DaveyTee wrote:
Will L wrote:Guess how I found that out.


The same way I did? viewtopic.php?f=7&t=1708

The Avonside jig appears to be the one generally favoured on this forum. I wonder if anyone has tried the Hobby Holidays one?

DT


Sorry David I have to admit to not remembering having seen that before, though presumably I have. Worth repeating for new purchasers though.

As for the Hobby Holidays Master Chassis you've obviously missed this one http://www.scalefour.org/forum/viewtopic.php?f=19&t=1018

Will

David Thorpe

Re: Avonside Chassis Clamps

Postby David Thorpe » Thu Dec 19, 2013 9:38 pm

Will L wrote:As for the Hobby Holidays Master Chassis you've obviously missed this one http://www.scalefour.org/forum/viewtopic.php?f=19&t=1018


Indeed I did, Will - thanks for pointing it out.

DT

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David B
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Re: Avonside Chassis Clamps

Postby David B » Fri Dec 20, 2013 8:08 am

You are not alone in your thinking about the clamps, Lindsay. I found them less than helpful.

David

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Jol Wilkinson
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Re: Avonside Chassis Clamps

Postby Jol Wilkinson » Fri Dec 20, 2013 8:58 am

I note that Avonside/EE have introduced a stripped down version

https://www.eileensemporium.com/index.p ... t&Itemid=9

Would anyone with experience of the all singing version care to comment on whether they would see this as a good purchase for the impecunious retired person?

Jol

the fatadder

Re: Avonside Chassis Clamps

Postby the fatadder » Fri Dec 20, 2013 9:21 am

I have no experence of the full version,
But I have the knocked down version you mention and find it very good.

The only issue I found with it was the metal base absorbing heat. In the end I bought some of the material used on the full version, (the name escapes me), and fixing that to the base.

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Andy W
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Re: Avonside Chassis Clamps

Postby Andy W » Fri Dec 20, 2013 11:08 pm

I use the HHS version and it's very straightforward with none of the tightening problems I've read about on here. As well as doing the aligning it also acts as a rolling road. I'm curious to hear why others prefer the Avonside version.
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Lindsay G
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Re: Avonside Chassis Clamps

Postby Lindsay G » Sat Dec 21, 2013 10:35 am

I was loaned one of the HH masterchassis a few months ago (which I didn't get round to using), but was warned by the owner that the pins could move slightly when they're tightened in the same way as the Chassis2 does.

It's maybe horses for courses, one has the ability to put the chassis together, the other has the rolling road. John Brighton has said they use both at Streamline. Perhaps another thread should be started on the pros and cons of both.

Lindsay

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grovenor-2685
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Re: Avonside Chassis Clamps

Postby grovenor-2685 » Sat Dec 21, 2013 11:24 am

Perhaps another thread should be started on the pros and cons of both.

No need for another thread, we already have one, just add to it.
http://www.scalefour.org/forum/viewtopic.php?f=18&t=1018
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Keith
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Keith
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