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11 hours ago, justin1985 said:

...But after fiddling with it, I think I'll have to make another fresh start with the quartering. I've put it away for now and I'll try to come back to it fresh again, after a break...

 

When you come back to it, check the axles are all in line. Insert 3 long lengths of axle steel through the bearings, and look along the length of the chassis.

If the axles are not parallel and in line, you will never successfully quarter the wheels.

Sometimes, screwing the body to the chassis can bend it up at the ends or twist it slightly.

Also, it has been known for the odd phosphor bronze bearing to have a non-concentric hole.

Quartering shouldn't be that hard, but my first experience of it was similar to yours. I never did get that particular chassis to run nicely. After many hours fiddling, it turned out to be slightly banana shaped. Don't give up though... it gets easier, and 14 years after thinking it was an impossible black art, my name is now on the Groves trophy.

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A bit late to this discussion, and you've already had advice from the experts, but as a bodger I'd echo Nick's points about making sure the issue really is the wheels rather than the chassis. My first 2mm chassis was a Raithby 4F banana that ran fine once I unsoldered it all and straightened it up.  My next couple of chassis were Jubilees and the big wheels made quartering by eye fairly straightforward. I've since acquired a jig and I too have found that in my hands it doesn't give perfect quartering, but it does get the wheels on straight which the slight waggle on my Jubilee chassis show I've found hard to do in the past. I now ream the muffs to an interference fit (as Chris mentions) use the jig to get the wheels to gauge etc and tweak quartering as needed before glueing them once I'm happy. How the temporary crankpin washers fit can have an impact as well as all the other things that have been mentioned; too loose and the rod can move out too far and cause issues (exacerbated by crankpins that aren't square to the wheel - clearly not your issue!) and too tight can cause other issues, particularly if your muffs aren't quite central between the frames or one of the flanged crankpins aren't pushed fully home.

 

Simon

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21 hours ago, Nick Mitchell said:

Sometimes, screwing the body to the chassis can bend it up at the ends or twist it slightly.

I recall someone, many years ago (it may have been Stewart Hine), counselling against using two screws to attach the body to the chassis as there was a very high chance that in tightening them you would distort the chassis.

 

As a consequence, I always only use one.

 

Jim

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1 hour ago, Caley Jim said:

I recall someone, many years ago (it may have been Stewart Hine), counselling against using two screws to attach the body to the chassis as there was a very high chance that in tightening them you would distort the chassis.

 

As a consequence, I always only use one.

 

Jim

 

I usually do the same Jim,

 

Jerry

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45 minutes ago, queensquare said:

Some might say both!

We're in our own little world, but it's OK, they know us there!  :D

 

13 minutes ago, richbrummitt said:

 

So how do you two align locate and secure both ends with one screw? 

I have a screw at one end, ususaly the smokebox end, and a couple of little pieces of styrene glued under the footplate at the other end to align the chassis with the body.

 

Jim

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Heh, but it is a little world that generates many ideas Jim, and some of us in the larger scales watch and borrow the good ones. 

 

So I would agree with just having one screw for a chassis and something like a slot with a bit of play at the other end. 

 

Indeed one of my locos has a screw at the boiler end and a press stud at the other, you can almost see the chassis twist with respect to the body. 

 

I keep looking round the flat and thinking about space for a bit of 2FS...... 

 

 

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Why use one screw when you can get four in?  It’s always worth checking a chassis, with the wheels, in place  against a piece of glass or mirror to see how flat it is to the track.  When you have locos that get handled by many people a bit more security in fixing is a perhaps a good idea. 
 

Tim

Edited by CF MRC
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I generally go for a screw at the front which will also hold the front coupling on with a pin or peg of some sort attached to the rear spacer to loosely locate in a hole in the rear drag beam or buffer beam where the coupling hook would be - I dont usually fit coupling hooks as they interfere with the delay latch on DG couplings. 

Twisting of the frames when bolted to the body is a particular problem with thin, etched frames which is where the heavy frames as used by Tim, John Greenwood and others on scratch chassis score. Best of all are the milled, solid chassis as on the Nigel Ashton GWR chassis block which is now available from the Association - these will twist the body to fit the chassis if its not square!

 

Jerry

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20 hours ago, queensquare said:

I generally go for a screw at the front which will also hold the front coupling on with a pin or peg of some sort attached to the rear spacer to loosely locate in a hole in the rear drag beam or buffer beam where the coupling hook would be - I dont usually fit coupling hooks as they interfere with the delay latch on DG couplings. 

Twisting of the frames when bolted to the body is a particular problem with thin, etched frames which is where the heavy frames as used by Tim, John Greenwood and others on scratch chassis score. Best of all are the milled, solid chassis as on the Nigel Ashton GWR chassis block which is now available from the Association - these will twist the body to fit the chassis if its not square!

 

Jerry

 

Putting in enough frame spacers can be just as if not more effective than thicker frames.

 

Chris 

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I've recently come into ownership of a Unimat SL - I've bought some tools for it, but I remember speaking to someone who suggested the use of a graver as opposed to tools held on the cross slide were useful for forming the complex curves of things like loco chimneys and domes. I've got an opportunity to turn up a pannier tank safety valve cover, and I can't help but think this would be best achieved using the graver method as described to me (though I a happy to be disabused of this notion).

 

CooksonGold supply square and lozenge gravers, and I can see that Amazon have a couple with handles and different grades- generally any advice or pointers on this would be greatly appreciated.

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1 hour ago, Lacathedrale said:

I've recently come into ownership of a Unimat SL - I've bought some tools for it, but I remember speaking to someone who suggested the use of a graver as opposed to tools held on the cross slide were useful for forming the complex curves of things like loco chimneys and domes. I've got an opportunity to turn up a pannier tank safety valve cover, and I can't help but think this would be best achieved using the graver method as described to me (though I a happy to be disabused of this notion).

 

CooksonGold supply square and lozenge gravers, and I can see that Amazon have a couple with handles and different grades- generally any advice or pointers on this would be greatly appreciated.

Hi

 

All gravers should have a handle as you don't want the bare tang in your hand.

 

Using the graver on the lathe you will need a T rest. There are a few articles on the internet about making one.

https://www.homemadetools.net/homemade-watchmaker-s-lathe-t-rest

https://www.homemadetools.net/forum/watchmaker-lathe-t-rest-graver-rest-27590

 

I made a mount for this one from H S Walsh for my Proxxon PD250 lathe.

https://www.hswalsh.com/product/bergeon-1766-06b-t-rest-26mm-hl1766e

 

I can take a picture later if required.

 

Cheers

 

Paul

Edited by PaulCheffus
Added second link for making t rest
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5 hours ago, Lacathedrale said:

I've recently come into ownership of a Unimat SL - I've bought some tools for it, but I remember speaking to someone who suggested the use of a graver as opposed to tools held on the cross slide were useful for forming the complex curves of things like loco chimneys and domes. I've got an opportunity to turn up a pannier tank safety valve cover, and I can't help but think this would be best achieved using the graver method as described to me...

A couple of years ago I posted a video demonstrating making a dome using a graver:

The graver I used was one I had ground myself from 1/8" tool steel and fit into a wooden handle. When you hold the end of the graver like a pencil (as you can see in the video) the handle fits in the palm of the hand. The whole thing is probably about 5" long.

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A brief question regarding resin casting open wagons. I want to do a large number (ultimately 30 to 40) medium opens (the BR ones with planked sides and corrugated ends). I have built / adapted a one piece master for the body, based on the NGS kit

 

What I’d like help with is which materials to try for creating the mound and casting the bodies because the learning curve seem quite steep and I want to focus limited time on actually modeling rather than experimenting. One specific is that I saw somewhere LEGO being used not just for the mound box but also to register the two mound halves which seemed like a really good idea...

 

Links to any useful relevant threads (I’ve done a lot of reading but it’s a question of not knowing enough to sort the wheat from the chaff) and any personal experience would be greatly appreciated...

 

Thanks in expectation!

Jim

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17 hours ago, Lacathedrale said:

I've recently come into ownership of a Unimat SL - I've bought some tools for it, but I remember speaking to someone who suggested the use of a graver as opposed to tools held on the cross slide were useful for forming the complex curves of things like loco chimneys and domes. I've got an opportunity to turn up a pannier tank safety valve cover, and I can't help but think this would be best achieved using the graver method as described to me (though I a happy to be disabused of this notion).

 

CooksonGold supply square and lozenge gravers, and I can see that Amazon have a couple with handles and different grades- generally any advice or pointers on this would be greatly appreciated.

Hi

 

One thing I forgot to mention. Don’t use gravers with a Chuck only use them with a collet.

 

Cheers

 

Paul

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18 hours ago, Lacathedrale said:

I've recently come into ownership of a Unimat SL - I've bought some tools for it, but I remember speaking to someone who suggested the use of a graver as opposed to tools held on the cross slide were useful for forming the complex curves of things like loco chimneys and domes. I've got an opportunity to turn up a pannier tank safety valve cover, and I can't help but think this would be best achieved using the graver method as described to me (though I a happy to be disabused of this notion).

 

CooksonGold supply square and lozenge gravers, and I can see that Amazon have a couple with handles and different grades- generally any advice or pointers on this would be greatly appreciated.

 

I have an SL and I use it a lot... but almost always with my ER16 collet holder which is great for holding work concentrically and as others have said, has fewer projecting bits to catch a graver, needle file or your hand on. My holder is from Arc Euro but I needed to make a backplate for it and I used a bigger lathe to make that and did the final turning of the register on the Unimat to achieve accuracy.

 

Another option are a ready made one from RCM Machines although this obviously won't be machined on your spindle...

https://www.rcm-machines.com/en/chuck-er/collet-chuck-er16-with-m12-x-1-inside-thread/rcm12er16

 

Or someone has very cleverly made a holder on the Unimat itself and posted a set of photos with informative notes...

https://www.flickr.com/photos/65657096@N00/albums/72157632104757918

 

I was going to make a tool rest for graver work but then I picked up a watchmaker's lathe so the graver work gets done there.

 

The unimat group on groups.io is well worth joining - it has tons of useful stuff in the files section as well as the forum.

 

Enjoy your SL !

 

Regards, Andy

Edited by D869
wrong url for RCM holder
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My graver (Vallorbe 3mm I think) and handle came from Eileen's. Buying a graver is the thin end of the wedge though - you also need to keep it sharp... for which you will need more things.

 

Some useful links relating to graver work. The Bergeon tool is not cheap. I made my own inspired by one of the other links below. You can get cheapy ones on eBay but a little bird told me that theirs was not useable as bought and had to be modified.

 

https://www.youtube.com/watch?v=gCb_ZHGb9ws
https://www.youtube.com/watch?v=gK-5s5jAg0c&t=373s

https://watchmaking.weebly.com/graver-honing-jig.html

 

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18 hours ago, Nick Mitchell said:

A couple of years ago I posted a video...

 

 

I've searched for one of those collet holding things and despite finding some pictures from dead ebay links had no luck. Anybody know where I can obtain one other than ask a friend with better workshop capabilities?

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1 hour ago, richbrummitt said:

 

I've searched for one of those collet holding things and despite finding some pictures from dead ebay links had no luck. Anybody know where I can obtain one other than ask a friend with better workshop capabilities?

 

It depends on what size/type of lathe you want to use. I would suggest here if it's for one of the smaller lathes:  https://www.arceurotrade.co.uk/

 

They can supply suitable backplates to go with them and the total cost is reasonable. I use a ER16 on my little Sieg as I didn't think I would want to go above 10mm dia size with it. It stays on it because the 3-jaw that came with it was total rubbish - as was all but the basic lathe parts - but at around £250 all up IIRC (with the collett chuck bits), it was a reasonable purchase at the time to do what I wanted.

 

Here's a couple of shots as I was about to machine up some more Farish 7mm coach wheels in case they are of help/interest.

 

458846923_RMweblathe01.jpg.70c20a40d730a13907fee8c11c232e03.jpg

 

717073659_RMweblathe02.jpg.1e0bb0ff4f03da3b78cc98b1cbd4123b.jpg

 

cheers,

 

Izzy

 

 

 

 

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2 minutes ago, Izzy said:

 

It depends on what size/type of lathe you want to use. I would suggest here if it's for one of the smaller lathes:  https://www.arceurotrade.co.uk/

 

 

Sorry. I should have been clearer. I have a WW pattern watchmakers lathe. It's the square bit of stock specifically machined to hold an 8mm collet that I seek. Nick uses it to hold the workpiece in the vice during filing and finishing the fit to the boiler.

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1 hour ago, richbrummitt said:

 

Sorry. I should have been clearer. I have a WW pattern watchmakers lathe. It's the square bit of stock specifically machined to hold an 8mm collet that I seek. Nick uses it to hold the workpiece in the vice during filing and finishing the fit to the boiler.

 

On bigger machines they are called collet blocks. They come in square and hex flavours and are handy for holding otherwise round objects while one mills squares or hex shapes onto them.

 

I haven't really looked very hard to see if one can be bought but I've put one for holding 6mm Lorch collets on my tooling 'to do' list. Trouble is that list is quite long.

 

FWIW, I've recently done a dome using methods inspired by Nick's video. For the filing job I stuck it in my ER16 holder which is easily taken off the lathe.

 

Regards, Andy

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I've a chimney to do for the pannier tank. At the moment though I'm stuck with a problem of a motor that won't turn the wheels. I've a few ideas to try but looking for the next distraction to have a break from that aspect and don't feel motivated to do the injectors yet.

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