Author Topic: Dummy rivets  (Read 11797 times)

0 Members and 1 Guest are viewing this topic.

Offline MikeWilliams

Dummy rivets
« on: November 12, 2009, 12:15:36 AM »
Having moved up from the smaller scales, I am used to embossing dummy rivets in etched brass kits.  I use an elderly Beeson tool and another made in the late 70s which has the advantage of an adjustable depth guide.  Both are intended for 4mm/7mm and to make larger rivets I make my own "dolly" from brass in the lathe.

I'm sure others don't do that, so it there a supplier of dollies suitable for our scale, or perhaps a tool which works better on our thicker material?

Mike
 

Offline cabbage

Re: Dummy rivets
« Reply #1 on: November 12, 2009, 07:15:48 AM »
GRS sell a "rivetting" tool I believe -but I take the approach that sticking them on is easier(!)

I get them from Cambrian Models.



regards

ralph

Offline John Candy

Re: Dummy rivets
« Reply #2 on: November 12, 2009, 09:43:36 AM »
I have the GRS rivet embossing tool ... .which is actually a 'Metal Smith' product---see  http://www.metalsmith.co.uk/metal-forming_tools.htm

I am not entirely happy with the results since the rivet heads are a bit too 'pointed' rather than round-headed and I prefer to use Cambrian plastic rivets and GRS brass rivets for my wagon construction.
Incidentally, Cambrian also produce a packet of assorted nut and bolt heads moulded in various shapes and sizes...very useful for (in particular) pre-group timber outside-framed wagons and vans.
The Cambrian louvres also very useful, as I have mentioned in previous postings.

Regards,
John.
« Last Edit: November 12, 2009, 10:51:25 AM by John Candy »
My fellow Members, ask not what your Society can do for you, ask what you can do for your Society.

Offline IanT

Re: Dummy rivets
« Reply #3 on: November 12, 2009, 10:40:52 AM »
I think the replies here are pointing up the differences in technique required as you go 'up-scale'. In 4mm it wouldn't make much sense to try to insert scale rivets - and the embossing methods became the norm. In 13.5mm, scale rivets are somewhat larger and drilling and glueing is much more practical - and I think they look better.

On a slightly different tack - on my Brandbright wagon kit - (instead of the white metal glue-in rivets supplied) I've used 12BA round head bolts (with the screw slot soldered over) so I get rivet heads on the inside of the wagon. I now have some 3/64th brass rivets that I'm currently experimenting with threading as a cheaper alternative (to the BA bolts) and the rivet heads are also slightly smaller. I did consider making scale nuts (square ones) as well but decided that life is too short. Ian D uses dress making pins on his wagons (I'm not sure his wife knows she is missing them yet) and they look very realistic.

It's very hard to get the 'base' to look right when embossing larger rivets (well at least on the thin sheet tin I was trying to use at the time). They tended to curve at the base too much - the ideal is a really sharp defintion between (what is supposed to be) the rivet head and the wagon side - but it's hard to do well. I imagine that a press tool using a round punch head into a carefully sized hole underneath with controlled stroke depth might do it - but discrete rivets look more like the real thing - so that's where I've gone.
Nothing's ever Easy - At least the first time around.

Offline IanT

Re: Dummy rivets
« Reply #4 on: November 12, 2009, 10:59:05 AM »
Having posted this - I looked at it and immediately realised that what I was talking about were not actually rivets. On my wagons I am of course trying to represent bolt heads. Ralph is refering to his locomotive plating and these panels would have been (I assume) rivetted and not bolted. In presentation the heads of coach bolts and rivets pretty look similar but I think the issues of construction remain the same.

My use of BA nuts and bolts was primarily because I wanted to show some inside detail on my open wagons, which sticking white metal parts on the outside didn't do (and which embossing doesn't achieve either).
Nothing's ever Easy - At least the first time around.

Offline MikeWilliams

Re: Dummy rivets
« Reply #5 on: November 12, 2009, 10:26:52 PM »
Thanks chaps.  The particular application is rivets on a loco smokebox wrapper which are half-etched on the back of the brass.  Since the smokebox has also to be formed to shape  I didn't want to emboss the rivets before rolling since that would involve some sort of packing to avoid squashing them.  After rolling its difficult to gain access, so I think I'll go with Ian's ideas and drill them all right through, roll the wrapper, and then insert either 1mm or 1/32in brass rivets, soldered off on the back.

If the GRS rivets are too pointed, maybe the striker itself is too pointed?

Thanks,

Mike

Offline Andy B

Re: Dummy rivets
« Reply #6 on: March 27, 2010, 09:03:34 AM »
I recently came across something useful in one of my local skips (see picture 1).
Sold as a tool for installing electrical terminal posts, I though it would make a good rivet punch.

After a quick clean-up with a bit of WD40 and wet'n'dry, I made a new bottom plate to hold the anvil, a new plunger to hold the punch, and an adjustable fence. (picture 2).

The anvil was made by using my smallest centre drill to create a small depression, then a small ball bearing was located in the depression and given a smart hammer blow (or 2!)
Result - nice round rivet heads with a clean edge (picture 3).
The strip shown is 0.020" thick - some of the rivets were half-etched, the rest not. Spot the difference!

At the AGM this year, Richard Thompson was using a Metalsmith punch, and I noticed that the rivets it made were rather pointed, as John observed above.
So I'd recommend a quick test to see if the Metalsmith anvils are hardened - if not, try the ball bearing trick as I did.
If they are hardened, and any of you would like to try an alternative, let me know the dimensions of your existing anvil and I'll make a test one for you to try.

Andy

Offline Traininvain

Re: Dummy rivets
« Reply #7 on: March 28, 2010, 03:42:06 PM »
I use a Metalsmith rivet tool with a G1 punch and a G3 anvil and it produces v nice crisp, rounded rivets on 0.7mm brass which compare well to using 1/32 brass rivets without the hassle and broken drills they entail

Ian

Offline Richard T

Re: Dummy rivets
« Reply #8 on: March 28, 2010, 04:13:43 PM »
I suspect the results you achieve  are due to not just the punch/anvil combination, but obviously the material thickness  ( I was embossing half etched 18thou half hard brass on my hopper wagon) and to an extent how you have set up your punch.
Even if you set the "depth" stop which restricts the downward movement of the handle, it can change over time and vary the results very slightly.
More noticable than the shape of the head to my mind is the "straightness" of the line and the reguarity of the spacing - that can really spoil a nice long run of rivets.

I think the Metalsmith punches are quite sharp, the one I was using at the AGM was a brand new one, but I have changed the form of some of the other size punches I have  but if you are punching plain N/S it is probably an advantage.

Going back to Mikes point regarding pre-rivetting before rolling, I have always riveted first, and using a fibrous type of cardboard or mounting board, succesfully rolled smokeboxes etc with no damage to the rivets

I'm afraid the idea of drilling holes and inserting rivets does not appeal to me at all - life really is too short - and I'd never finish anything off !

Richard

Offline andrewfoster

Re: Dummy rivets
« Reply #9 on: August 23, 2010, 07:38:10 PM »
I've just joined the forum, so I have a bit of catching up to do. I have to admit that I enjoy rivets and riveting, though my grandfather, who set his share of them in Scott's shipyard in Greenock, would probably have thought it lunacy to use them after welding became commonplace. However, he's no longer around to put me right...

As usual, there's a prototype for everything, and pointed rivets with almost conical heads will occasionally be found, but generally on very old machinery, like early locomotive boilers and traction engines. I use mainly round head ("snap head") rivets on my bridges, and most are 1/16" (1.6mm) aluminium, which are fairly straightforward to set. You can find smaller ones, but they are tedious to handle, usually needing tweezers. I use several proper riveting tools, such as an aircraft rivet squeeze, but to be honest (and to give away a trade secret!) one of the most useful tools is a small drill press with the die in the chuck and an anvil below. You could easily adapt this kind of press for embossing imitation rivet heads by shaping the anvil and adding a fence to get straight lines. Instead of the usual squeezer dies, I'll often use a slightly modified 1/8" carpenter's nail set to form the heads, and get good results. Nail sets vary a lot in their design and quality, but if you choose the right one, it forms the head well and does no damage to the adjacent material.

Another essential time saving tool is the 'cleco' used by aircraft mechanics. They are used to line up the parts and hold them together using vacant rivet holes.

Having said all that, I'll concede that embossed rivet heads serve a very useful purpose if they are done well, and I've admired a great many of them. It's not everyone who can tell the difference through a good coat of paint!

Andrew

Offline MikeWilliams

Re: Dummy rivets
« Reply #10 on: August 23, 2010, 09:30:17 PM »
Welcome to the forum Andrew.  From your interesting post I just have to ask for more information please on "my bridges" !

Mike
 

Offline John Candy

Re: Dummy rivets
« Reply #11 on: August 23, 2010, 10:48:35 PM »
Here is a link to Gnome Miniature Engineering, the business run by Andrew Foster, producing bridges for large scale modellers.
An entry also appears in the "Trade Window" section of www.gauge3.org.uk

http://gnomengineers.blogspot.com/
My fellow Members, ask not what your Society can do for you, ask what you can do for your Society.

Offline andrewfoster

Re: Dummy rivets
« Reply #12 on: August 24, 2010, 12:15:54 AM »
Thank you for the friendly welcome! The website is pretty much self explanatory, but I'm always happy to answer questions about the products.  By way of background, we began with turntable designs (from 500 to 1,000mmm diameter) but were diverted into the bridges for various reasons. Part of the design philosophy comes from seeing some very expensive rust on a few garden railways. It really doesn't cost much extra to design for the environment.

The basic bridge range is just about complete now (I hope it will never be really complete...) and we hope get back to the turntables soon. They will built along the same lines, in riveted aluminium alloy for outdoor use, with remote control available.

Andrew

Offline MikeWilliams

Re: Dummy rivets
« Reply #13 on: August 24, 2010, 04:25:56 PM »
Very nice Andrew.  I particularly like the plate girder, of which there were very many in the UK.  I had hoped to make one myself one day, but yours look realy nice.

Mike

Offline andrewfoster

Re: Dummy rivets
« Reply #14 on: August 24, 2010, 06:42:59 PM »
Well; thanks again! Starting to drift off topic, but it's interesting that the plate girders are more popular than the Warren trusses, and I don't really know why. Is it because a short plate girder looks better than a short truss? I don't know. What I do know is that there is hardly a rivet in the plate girder that can be handled with fingers - almost every one of them has to be placed into the angles with tweezers in the absence of the kind of equipment used for mass production. The trusses are a bit easier to assemble, but then there's more cleaning and deburring of the parts. In an assembly of three spans there can be well over a thousand rivets. All this contributes to the price structure, of course, and I struggle to maintain that fine balance between outrageous and scandalous.

Andrew