Penrith Beacon's Workbench

[PenrithBeacon]

I thought that as I wanted to make up the RT Models 100hp Sentinel kit that I bought at last years Scaleforum I might as well share the experience. In general though this thread will cover RTR conversions as well, simply because I'd very quickly loose sight of what I'm doing if I had a multiplicity of threads.

So, the Sentinel. The box costs £100 and it has pretty well everything in it that you will need, excepting, as far as I can see, the odd bit of wire. The instructions are OK but the pages are not numbered and the print of the layout of the etches is different to the reality! The components are numbered in the destructions but not on the etch.

I started by riveting the cab. Snag 1! I have an LRM riveting tool but I couldn't get it to work on the RH etches. The half etch holes for the rivets are very small, tiny things, and I came to the conclusion that the LRM tool's cone was too flat to make an impression. It was distorting the nickel silver but not producing rivets. I suspect things would be different if the holes were larger. So to plan B and the use of a scriber point. This is OK but it has the difficulty of not being consistent and it shows. Many of the rivets are very close to the edge which distorts the workpiece and occasionally bursts through the edge. When I finished I immediately got on the phone to GW Tools with a view to buying a riveting tool but I was out of luck, none in stock but I'm now on the list.

The photo below shows the state of play at this time. I should say that I forgot to adjust the cameras white balance so the picture's colour is pretty odd



After a bit work to clear up the distortion I got this:



The holes for the various commode handles are missing off the etch and the destructions have an apology for this and a paper template is supplied to rectify the issue. I managed to break two 0.8mm drills while doing this! The damned pin vice kept on rolling onto the floor.

Then I folded up the cab and the loco's bonnet using the supplied template as a guide:



At this point I realised that I had actually stared at step 2! Step 1 is to assemble to footplate/platform. Using my recently acquired Huron etch scissors (a real boon these, expensive but well worth it), the components were cut from the etch sheet. The buffer beams were soldered up and cleaned (the end 'flaps' go inside the front and back, a neat piece of design) and that was as far as I have got because my eyes had had enough.



Perhaps more tomorrow.

Regards

[buffalo]

Sorry to see you've had that problem with the LRM tool. I had the same with the very first kit I tried mine on which rather put me off it, although it does work quite well when the half-etched holes are large enough. Interestingly, I don't think I've seen this mentioned in any of the discussions on here about rivetting tools. Despite having several tools, my favourite is still a slightly blunted scriber, even though it is a bit hard on the fingers. At least it looks like you've made a reasonable recovery.

 

Nick

[PenrithBeacon]

Sorry to see you've had that problem with the LRM tool. I had the same with the very first kit I tried mine on which rather put me off it, although it does work quite well when the half-etched holes are large enough. Interestingly, I don't think I've seen this mentioned in any of the discussions on here about rivetting tools. Despite having several tools, my favourite is still a slightly blunted scriber, even though it is a bit hard on the fingers. At least it looks like you've made a reasonable recovery.

 

Nick

I had come to much the same conclusion re the size of the holes. I don't think the LRM tool actually gets to the bottom of the hole because they're too small for it. Never mind. The blunt scriber is OK but doesn't give consistency and my increasingly arthritic hands play up.

 

Regards

[Jol Wilkinson]

The holes along the top of the cab front are close to the edge and those will always be difficult to do with anything except a "punch and anvil" type of riveter (like the GW version. Because one side of the rivet hole doesn't have a lot of support from the surrounding metal, distortion will be a problem. The anvil supports the metal better in such cases as the punch or die is applied. You can also set the depth with the GW tool which helps in such circumstances.

 

It also helps if you can find a suitable backing material when using a gravity riveter or scriber. I find 1.0mm plasticard works well. Some kits also have "test" rivets in a scrap area of etch to experiment with.

 

Jol

[buffalo]

...It also helps if you can find a suitable backing material when using a gravity riveter or scriber. I find 1.0mm plasticard works well...

Yes, essential. A sheet of lead is also very good as backing.

 

Nick

[PenrithBeacon]

I used the cutting mat (too soft), then a piece of MDF (too hard) and then a piece of thick card (just right)! Thanks for the replies.

 

Regards

[PenrithBeacon]

Did a bit more this afternoon in what became two and a half hours quite intense modelling. Feel quite weary now!

 

The next part of the job was the platform/underframe and buffer beam all of which form a sub-assembly. The destructions imply a method of assembly by virtue of the part numbers, ie 1,2 3, and 4. There are no alphabetic instructions here. I thought that I would change the order of the assembly a little by soldering part 4 (buffer beams) to part 1 (the platform) first. I did this because I thought that the buffer beams would form a heat sink if I did them first whereas if I did them last, the amount of heat required to solder them onto part 1 might cause the other parts to come adrift. Whatever, this is how I did it.

 

First, the buffer beam. It was essential to get these square to the platform:

 

 

The location was by two slots and tabs with no adjustment of the fit being necessary. The other end was done in the same way:

 

 

Next the valences. These are a pain! The only location is a half etch line underneath the platform. I have used self locking tweezers in similar situations before, but on this occasion they were too strong and just flattened the valance against the platform. However, a bit of masking tape came to the rescue, but I think that if the valances were extended into the buffer beams via slots this would be a great help.

 

 

The other one was done in the same way.

 

 

I'm not at all sure that I have got the valances entirely right, but it's the best I can do for now. You can see that there's a gap between the end of the valance and the buffer beam and there's a hint that the valance might not be entirely located in the slot. The valance also needs a touch of filler to cover the gaps at the ends.

 

Next the underframe, this is nicely done, with slots in the platform and tabs on the underframe fold-up. There are also elliptical (or perhaps just ovals) holes in the ends of the underframe to assist in soldering the two parts together.

 

 

 

That's all for now. I might get more done over the weekend, but it looks to be pretty busy for now!

 

Regards

[PenrithBeacon]

Did a bit more today, not a lot because I had to sober up after two pints down the pub.

 

I was a little disappointed with yesterday, and wanted to work out why. Firstly I think the instructions are right to imply that the buffer beams go on last. The gives an opportunity the file down the platform a little so that the valances don't appear to be short. The valances can be held in place with masking tape while the buffer beams are being soldered up so they don't fall of while doing this. Secondly the valance issue. I think this was caused because I only used one piece of tape to hold that valance down (see the photo in yesterday's post); this allowed the part to move during soldering. The second valance was held on with two pieces of tape and the movement didn't happen. Still, a lesson learnt.

 

Today I decided to try to correct the valance issue in which a was only partially successful, but it is better. I also soldered up the buffer beams to the underframe which makes the assembly much stronger, making sure that the valances were securely held with masking tape. The tape got hot which left a sticky adhesive residue behind but this was quickly cleaned up.

 

So to today's progress. Two nuts have been soldered to the platform and the two formers for the bonnet have been soldered in place. I used a very short length of hardwood beading to get them square. If anyone has any other ideas of how to get components square I'd like to hear them.

 

Before soldering

 

 

After soldering

 

 

Both formers in place and cleaned up

 

 

Regards

[PenrithBeacon]

I haven't done any work on the project for a week or more. The reason for this was that the instructions for the next stage say the bonnet, cab and a piece of rivet detail that goes round the bonnet and cab 'can be fiddley' implying that they were to be assembled at the same time. The problem here is that the rivet detail is extremely fragile and it's all too easy to bend it while filing the tabs off as I found out to my cost. I therefore put the work down until I worked out how to do this one component at a time. Inevitably family matters intervened too.

 

Anyway, today I managed to get in about four hours work, and it's proved to be quite successful although the results aren't absolutely perfect by any means. I leave perfect to others!

 

First the rivet detail:

 

 

As can be seen three narrow pieces of masking tape were attached to the component. This was done while it was upside down on the cutting mat. Then the component was cleaned up with a fibre glass brush. Following this little blobs of solder paint were applied using a cocktail stick, but very sparingly; the detail was then offered up to the platform as can be seen above and below.

 

The parts were then soldered up using a dry iron while pushing the detail down with a scalpel.

 

This photo shows the work after soldering but before cleaning up.

 

 

And after cleaning up

 

 

The other side was then done in the same manner.

 

The bonnet didn't fit too well at first and it was necessary to file radii on the corners of the bonnet formers to allow the radii in the bonnet corners to fit. This doesn't, I think, need to be done too carefully, but it is clear that it does need to be done. Also the tabs on the bottom edge of the bonnet need to be filed down too. They're pretty small as supplied, but not quite small enough. Then the bonnet fitted quite snuggly and was soldered to the platform from the inside. There was a similar issue with the cab but when it too was resolved, the cab was soldered, again from the inside, to the platform. There is a gap between the bonnet and the cab (no tabs on the bonnet to secure it to the cab); this will have to b resolved later by using filler. I didn't want to use solder here, it would be the very devil to clean up as any soldering would have to be done from the outside.

 

 

 

 

So, that's it for today. The next job, after cleaning up, is to paint the inside of the cab as it won't be possible to do it once the rear section of the cab is fitted. This rear section will painted at the same time. What few resources are available to me suggest that the cab insides were painted black and white, ie white above the cab cut-out sill and black below. The cladding of the boiler seems to have been a mid-grey. If anyone knows different I'd be grateful to hear from them.

 

Regards

[Kenton]

 

The next job, after cleaning up, is to paint the inside of the cab as it won't be possible to do it once the rear section of the cab is fitted. This rear section will painted at the same time.

That is going to make soldering it in place a bit difficult. Maybe there is a way to make the cab back removable? This is a frequent problem with enclosed cabs.

 

BTW another vote here for the GW rivet press (I would have said earlier, but have just come across this thread) It is much less distressing to use and produces very even and clean rivets. Well worth the investment if you are building lots of kits.

 

I've had my eye on one of these kits, am a little saddened to hear that the instructions are a bit disorganised and potentially wrong.

[PenrithBeacon]

 That is going to make soldering it in place a bit difficult. Maybe there is a way to make the cab back removable? This is a frequent problem with enclosed cabs.

 

BTW another vote here for the GW rivet press (I would have said earlier, but have just come across this thread) It is much less distressing to use and produces very even and clean rivets. Well worth the investment if you are building lots of kits.

 

I've had my eye on one of these kits, am a little saddened to hear that the instructions are a bit disorganised and potentially wrong.

I really don't think there's anything wrong with the kit. The destructions are no worse than some and better than many. Just needs a bit if thought! Worth buying I think.

 

Regards

[PenrithBeacon]

 That is going to make soldering it in place a bit difficult. Maybe there is a way to make the cab back removable? This is a frequent problem with enclosed cabs.

 

...

The plot is to leave an area at top and bottom free of paint, do the soldering and then touch up the paint. There isn't going to be a lot of space in there and there won't be a lot of light either. I can't see how to make the cab come apart without a fair few mods which I'd rather not do. Adding nuts to the cab sides and screwing together from the bottom could be done, but as the bonnet doesn't extend into the cab, even by a little, there's going to be a gap between boiler and cab which will need to be filled. The loco isn't designed to be assembled in a modular fashion and as it's so small it doesn't lend itself to modular assembly. Perhaps the next time I take a photo I might include the traditional coin to give scale! I know of a good many wagons that are larger than this engine!

 

The biggest challenge in the painting is going to be getting the demarcation line between the black and white straight. I've bought a sheet of block black water slide transfer, the idea is to use this to get the straight lines and then fill in with paint, finally spraying over with satin varnish. Best laid plans!

 

Nobody should be dissuaded from buying this kit by my 'warts and all' approach. It is true that few details in the design could be improved, but a complete kit, absolutely complete, of this quality for £100 shouldn't be sniffed at.

 

Regards

[PenrithBeacon]

Something has been nagging at me for the last few days about the kit and a few moments ago I took some time out to look at it. As described earlier the destructions say that 0.8mm holes should be drilled into the cab sides and photos show handrails and handrail knobs in these positions. The problem is that the fixing spigots on the handrail knobs supplied are a good deal smaller than 0.8mm. This means that the holes will have to be filled and started again. I have edited post#1 to warn anyone about this error, and I'll get back as to the solution I adopt later.

Regards

[buffalo]

Possibly a change of knob supplier, Gibson knobs need a 0.85mm hole.

 

Nick

 

ps. If they are shouldered knobs, the over-sized hole shouldn't be a problem.

[PenrithBeacon]

Following on from 'Buffalo's' post above I decided to look again and found that the error is mine, not the kits. Embarrassing isn't in it, but I got it wrong. On such a small model 0.8mm looks enormous and I was worried. Sorry and thanks to 'Buffalo'.

 

Post #1 has been re-edited.

 

Regards

[sej]

Hi David, a very interesting build of a nice little loco. I particularly like your wood block and masking tape soldering aids and will be trying out the masking tape myself, I've been a bit of a blu-tack fan so far.

Nice to see some before and after soldering clean-up photos too, what methods do you use to get rid of the excess?

I'm a firm favourite of the GW rivet press, it is a fantastic piece of kit.

 

Looking forward to further instalments.

 

Cheers

Simon

[ozzyo]

Looking at the rivet strip that goes under the bottom of the bonnet and cab, I'd have just placed the bonnet in place through the slots and tack soldered the tabs in place, then done the same with the cab. After that it should have been a matter of seam soldering along the bottom joints from the inside. For doing this sort of job I have a soldering iron bit that I have bent to approx. 90degs to help do this sort of job. 

 

A good riveter with an anvil is a must on these sort of jobs, drop riveters with out a good firm support behind them only distort the metal.

 

OzzyO. 

[PenrithBeacon]

Ozzy,

 

The rivet strip is designed to fit under the bonnet. I know it's perhaps not too clear but it can be seen extending under the 'place' the bonnet is intended to fit. The bonnet fits over the formers. I would have preferred to rivet strip to extend to the cavity in the middle of the platform etch so it would have been less fragile.

 

 

 

Regards

[PenrithBeacon]

Simon,

 

I use a scalpel, roughish flat swiss file, emery and a fibre glass brush to clean up solder. But I try to be as sparing as possible with the solder because the less I use the less I have to clean up. The use of solder paint is an innovation as far as I'm concerned. It works well.

 

I know this will seem to be very iconoclastic to some, but I'm not an enthusiast of using solder in a seam unless the two components really need to have the additional strength. On this model so far 'seam soldering' has been restricted to the platform/valance and valance/buffer beam. If I need to use a filler later, and I will, I will use a modern filler such as Squadron Green rather than solder. It's so much easier to clean up.

 

Regards

[ozzyo]

Looking at the rivet strip that goes under the bottom of the bonnet and cab, I'd have just placed the bonnet in place through the slots and tack soldered the tabs in place, then done the same with the cab. After that it should have been a matter of seam soldering along the bottom joints from the inside. For doing this sort of job I have a soldering iron bit that I have bent to approx. 90degs to help do this sort of job. 

OzzyO. 

 

 

Ozzy,

 

The rivet strip is designed to fit under the bonnet. I know it's perhaps not too clear but it can be seen extending under the 'place' the bonnet is intended to fit. The bonnet fits over the formers. I would have preferred to rivet strip to extend to the cavity in the middle of the platform etch so it would have been less fragile.

Regards

 

If I'm looking at the job correctly this is how the parts fit, as in my sketch below,

 

All you should have to do is tack solder the tabs from below, then when the parts are in the correct place seam solder them in place from the inside. Looking at the way the body is made you should be able to do most of the soldering from the inside. As I mentioned I have bent a soldering iron bit to about 90degs so that I can do this sort of soldering. 

 

OzzyO.

 

PS. try using 145deg. solder for this type of job.

[PenrithBeacon]

If I'm looking at the job correctly this is how the parts fit, as in my sketch below,

drwings 006.jpg

 

All you should have to do is tack solder the tabs from below, then when the parts are in the correct place seam solder them in place from the inside. Looking at the way the body is made you should be able to do most of the soldering from the inside. As I mentioned I have bent a soldering iron bit to about 90degs so that I can do this sort of soldering. 

 

OzzyO.

 

PS. try using 145deg. solder for this type of job.

Apart from running a seam along the inside of the bonnet and the 'degree' of the solder this is how I did it. The tip about the bent iron bit is useful, Antex don't do one for the 18W iron (I have tried before from Squires), but I suppose I could buy a straight one and bend it!

 

Thanks for the advice

 

Regards

[PenrithBeacon]

I said in an earlier post that the model was very small for a loco, this photo says just how small.

 

 

A little more work was done today, but I have put the loco body to one side in favour of the chassis. This is because the body is getting close to the point where I will have to work out how much lead can be fitted under the platform and inside the bonnet. To do this I shall need to know just how much room there will be at the top and sides of the bonnet after the motor and gearbox are fitted and it will be best if I can see this rather than doing it by trial and error, never a good way of working.

 

So, here goes!

 

Firstly the chassis was cut out of the fret and the tabs filed off.

 

 

Examining the part under the magnifier it became clear that the designer hadn't relieved the corners, so I could expect some distortion in the fold-up if I didn't do it. A razor saw was used to cut a slight slot in the corners. As the saw has teeth that are at a greater pitch than the thickness of the material, the saw was drawn towards me rather than the usual 'push away' action. Essentially I wore rather than cut the slots in the fold-up. Also the ends of the 'end flaps' of the chassis needed a little work with a file to get them to fold inside the side members of the chassis.

 

 

The photo only shows two corners, but this has to be done to all inside corners on the component.

 

Then had this, showing the chassis fold up before soldering on the inside of the corners.

 

 

Then I offered up the chassis to the body just to make absolutely certain that there were no issues. There were non.

 

 

Then the central knife edge for the compensation (Part 101) was folded up and soldered into the chassis fold-up.

 

 

 

Now for what proved to be the only awkward part of the afternoon. There are components which are designed to 'pack-out' the chassis for EM and P4 modellers. These take the form rectangular pieces of the fret with either a round or elongated hole in them. They have to soldered together and then soldered to the chassis on the outside. Can be done of course but it would be better if they were a fold-up and had a form of location built into the design. Anyway, the first one was located on the chassis and then soldered, using solder paint, from the inside.

 

Before,

 

 

And after,

 

 

The second was also done. Top hat bearings are supplied which are intended to go inside the holes, but the holes are quite a lot smaller than the bearing and so a lot of work was needed with a broach to get the fit. Once the fit was obtained the bearing was soldered in.

 

 

Unfortunately the use of the broach has raised a blister on my right forefinger so work is going have to stop until that heals, although I will be able to work on other projects in the meantime.

 

Regards

 

I really don't understand the rhyme and reason about adding photos to posts. There are two additional photos in the post which I thought had been deleted and another which is in the wrong place. Sorry! Ignore the photo immediately above and below!

[PenrithBeacon]

I managed to get a little more in this afternoon, but first let me show my new piece of kit. I'm looking forward to learning how to use it!

 

 

Since my last post I've been thinking on and off about the chassis and I've decided to make a few changes. Firstly the fixed axle. I think that, as designed, it's not really right. The packing pieces look to be a bit of a bodge, all very untidy. So, I unsoldered them and the supplied top hat bearing and then re-soldered the top-hats using the standard technique of a long length of rod to ensure the alignment of the two bearings. The wheels will still require 'packing' to limit the side-play but I shall use 2mm washers to achieve this. Both AGW and Branchlines do very good 2mm washers.

 

 

Now the compensated axle where I have decided to use standard High Level hornblocks. This is because I really don't have the confidence that I have the skills with the file to open out the slots provided so that the compensated axle will both be parallel to the fixed axle, the slots square with each other with the top-hats a slide fit in the slots. A long way beyond my capabilities I think, but if that isn't achieved then the loco will come off the tracks particularly when it meets a point. Also I have a concern with the top hat bearing sliding up and down in the slot. Wear on the top hats could be quite severe which will also render the loco at risk whenever it meets a point. One way or another I'm unhappy and I've decided to use the tried and tested technique for compensated axles of hornblocks.

 

But there is a fly in the ointment. There isn't enough metal on the chassis to solder in hornblocks.

 

The solution I have adopted is to solder a brass strip onto the chassis to give a greater width. This should permit the use of horn blocks.

 

 

 

In these photos the top brass strip has been soldered on and partially trimmed up while the bottom has just been soldered. Both have since been trimmed so they are more are less the same, ie they are flush with the top of the chassis fold-up.

 

That's as far as I got today. In my next post the axle centres will be measured and the dimension, I think it's pretty close to 19mm, will be used to mark out the horn cut-outs. Then the hornblocks will be soldered in. I think this will mean that I have to make up a pseudo set of 'coupling rods' on order to use the LRM jigs. We will see.

 

In the meantime, does anyone know of a source for a 4mm drawing of these engines?

 

Regards

[PenrithBeacon]

Three hours more today, although it feels like a lot more! I had quite forgotten just how tiring detail marking out and filing is. Not done it for tens of years so the results below are not at all up to professional standards. I'm completely out of practice.

 

Firstly I needed to check the wheelbase, as expected it was 19mm, give or take. The two drills are 1mm diameter.

 

 

I thought that some RMwebbers might like to see the marking out setup I used, dimly remembered from an apprenticeship of more than 50 years ago now.

 

 

I was given the Vernier Height Gauge by my Dad when he retired in 1978. I've hardly used it since and I had completely forgotten how it worked! Never mind, got there in the end. Trying to find the dimensions of the horn cut-outs was interesting. The first stop was the CLAG website and couldn't find them. They're not in the S4 manual and I eventually found them in the EMGS Manual under an item describing the Kean-MayGib hornblocks which disappeared from the market tens of years ago.

 

The chassis marked out:

 

 

And filed with rather unprofessional results, sorry! I had to remove the central knife edge (Part 101) for safekeeping before filing.

 

 

Next up folding the High Level hornblocks and soldering them in, but that's for another day.

 

Regards

[PenrithBeacon]

Did a bit more today. In my last post I mentioned that I was going to use the LRM jigs to position the hornguides. A few days later and it dawned that this wasn't going to be possible because the LRM jigs are specific to 1/8" axles and the kit uses 2mm axles. So, the thinking cap went on and I decided that if the worst came to the worst I would have to make a 2mm equivalent to the LRM jigs. It did ...

 

At first I folded up the High Level hornguides and married them to the MJT 2mm bearing which I also had in stock. These were then presented to the chassis using a length of rod and a spring to keep the hornguides up against the inside of the chassis side plates. So far, so standard.

 

At first tried to get by without any jigs at all. I used the digital calliper set to 21mm (ie 19mm hole centres plus 2mm for the axle diameter) to set the axles at the right pitch but the helix in the spring just kept on throwing the axle out of square.

 

 

This was clearly unacceptable so I cut two lengths of strip, soldered them together and marked out for two holes at 19mm pitch. I also centre punched two pop marks on both side of the workpiece to indicate their orientation for later.

 

 

Then they were drilled using a 2mm drill. I did wonder if I ought to have drilled 1.8mm and then reamed 2mm but I decided against, but it might have been Plan B.

 

 

The two pieces of drilled strip were then threaded through the axles to position the axles at a nominal 19mm and the hornguides were soldered up.

 

 

After leaving the work a while to cool down the two drilled strips were removed and the digital calliper was used to check the pitch of the axles. One side came out at 20.68mm the other 20.80mm which I thought compared very well with the required nominal dimension of 21mm. Certainly the difference of .12mm was far better than I had hoped for.

 

The axles and spring was removed leaving me with a compensated chassis. Yippee!

 

 

That doesn't take too long to describe but there was about three hours work in that!

 

Next time the chassis will be finished and I'll take a look at the gearbox.

 

Regards