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Lowmek


D869

1,463 views

There hasn't been a great deal to report here recently. It's not that I haven't been doing anything, just that a good deal of it has been kit assembly or repeat builds.

 

There is one job that I did started shortly after the 2mm Expo that I thought would benefit from a few words here. We were a bit more relaxed at the Expo with mixing and matching locos to different trains. At one point this ad libbing caused us to come unstuck. My Hymek was moved from its usual local passenger turn and put onto the mineral train. It arrived smoothly into the loop and then came to a sudden and mysterious halt. A little investigation revealed the cause - it was too high to go underneath the 3 doll bracket signal that had been installed just before Railex.

 

The signal had been checked for clearance with various vehicles, but clearly not the Hymek. The fact that Dapol Hymeks are, well, too tall is pretty well known and Jerry Clifford has written a few words about how he improved one of his examples. I'd been intending to do something similar to mine for a long time but had never actually got around to it. I had no intention of modifying the signal, so the Hymek had to get lower.

 

I read Jerry's description of how he did it. If memory serves, he said that he took out the PCB and also filed the bottom of the cab front panels to allow it to sit lower on the buffer beams. I started to strip my own loco down to see for myself what was needed to make it lower… The PCB came out and the motor wires were soldered to the pickups (see photos). Rather than start filing the body away, I just removed the buffer beams temporarily... No joy.

 

blogentry-9623-0-65264600-1381217813_thumb.jpg blogentry-9623-0-66266000-1381217831_thumb.jpg

 

I started to look at what was still propping the body up. I tried taking a couple of the engine bay windows out but that didn't help either. Some investigation with squashing lumps of Blu Tack between the top of the chassis and the body proved that there was loads of headroom over the chassis. After a good deal of rocking the body to see where it was being supported I found that it was the rear of the cab door handrail recesses. These stick out inside the body and their bottoms rest on the 'ledges' at either end of the chassis.

 

I cleaned up the back of the handrail wire and chamfered the bottom edge of the plastic that surrounded it. I also made a chamfer on the top edge of the chassis (see the picture) to allow the handrail recesses to sit lower down. Success!. At the next group meeting the loco was tested under the bracket signal and it passed with room to spare.

 

blogentry-9623-0-68552600-1381217890_thumb.jpg

 

Having figured out the answer I then put the whole thing down and worked on other things for a couple of months.

 

Now we have the Aldershot show this weekend, I thought it was about time that the Hymek went back together. There was still one job remaining though - I hadn't done anything about the buffer beams (other than removing them).

 

My answer for the buffer beams is a bit different to Jerry's. I wanted to fix the buffer beam to the body rather than having it glued to the chassis and then modify the chassis to let the whole lot sit lower down. I first used a sharpened screwdriver as a chisel/crowbar to undo the Dapol glued joints and detach the buffer beam from the lighting surround and PCB. The coupling hook also had to go otherwise it would foul the DG coupling. The photo below shows the buffer beam stripped into its component parts and also how Dapol intended it to fit onto the chassis.

 

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I did a little bit of filing to the bottom edge of the cab front but only enough to allow the buffer beam to sit snugly where it should. The two central 'lugs' were cut off the buffer beam. The buffer beam was then glued to the body with Formula 560 Canopy Glue (this is my default glue for lots of jobs now), adjusted for the correct alignment and then left to dry before adding more glue to strengthen the job.

 

Attaching the buffer beam to the body now means that you can't drop the body onto the chassis. There are two answers to this. My first answer was (after masking the moving parts of the chassis) to file away a rectangular chunk from the front corner of the chassis - see the shiny parts of the chassis in the photo below.

 

blogentry-9623-0-29284600-1381217868_thumb.jpg

 

While doing the second corner and congratulating myself on how careful I was being not to break the brittle Mazak chassis moulding… it snapped. So… method 1 is to be more careful than I was so that you don't snap off the end of the chassis. I then convinced myself that I had brilliantly invented method 2 and it was the better way because it avoided the risk of getting metal filings into the mechanism completely. I took some chunky wire cutters and cut off the opposite 'ledge' that I had managed to file without snapping. This also removes the need to file the chamfers to allow the cab handrail recesses to sit lower down. The disadvantage of this method is that the height control for the body moves elsewhere and is less easy to adjust. I think it is now the engine bay glazing but I'm not 100% sure. A small amount was also shaved from the bottom of the buffer beams to ensure that the body was not resting on the top of the DG coupling. Naturally it will also make it more difficult to re-fit the lighting unit if I ever decide to do that.

 

The stats - before I started I measured the height as 28.5mm. The correct height should be 12.88 ft which scales to 26.55mm in 'N' scale. After all of the surgery so far it is now down to 27.25mm. Here's how it looks now.

 

blogentry-9623-0-88332800-1381231111_thumb.jpg

 

Incidentally, for the benefit of those DCC types… I think that there is probably enough room between the chassis and the body to leave the PCB in place. I now have some wires in the way though so I have not actually tried it.

 

This is not the finished article yet but its appearance is much improved and I think it will be turning a wheel at the Aldershot show in its current state. If my theory about the engine bay windows is correct then it might be possible to lose another 0.5mm or so but I am undecided about whether that's a good idea. In any case it will involve taking out all of the windows so is definitely a job for another day. Once I'm happy that no further surgery is required then I might finally get around to weathering it.

 

Edit: here's the front(ish) photo that Jerry asked for. Shows up the less than perfect paintwork around the windscreens nicely doesn't it?

 

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Great work Andy and a considerable improvement.

 

Glad you've discovered the Blu-tac school of engineering as well :)

 

Hope the show goes well?

 

Cheers,

 

Mark

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Great work Andy and a considerable improvement.

 

Glad you've discovered the Blu-tac school of engineering as well :)

 

Hope the show goes well?

Thanks Mark. I feel that Blu Tack is definitely the choice of the discerning engineer. I was considering writing an article on its many uses but I think it would be too long ;)

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  • RMweb Gold

Looks good Andy and proves that there are more than one way to skin a cat - or skim a Hymek! Any chance of a front on view. I suspect your method of fixing the buffer beam to the body rather than my trimming the body to get it to sit lower will look better.

As for Blu Tack, along with cocktail sticks, it is indeed the first choice of all discerning modellers!

 

Jerry

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Looks good Andy and proves that there are more than one way to skin a cat - or skim a Hymek! Any chance of a front on view. I suspect your method of fixing the buffer beam to the body rather than my trimming the body to get it to sit lower will look better.

Thanks Jerry - front(ish) photo added.

 

Regards, Andy

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  • RMweb Gold

Thanks Andy. The join twix body and buffer beam on yours looks neater than mine so I shall be stealing that idea as I still have two to do. I notice you have fitted a loop and dropper on the DG, I will be interested to see how much of the front end plumbing you can still fit on. One of the advantages of my fitting loops on both ends of my stock is that I don't have to fit any on locos and can also trim down the little wings of the buffing plate.

 

cheers Jerry

 

ps. I am going to try to get up to Aldershot at the weekend. 

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Thanks Andy. The join twix body and buffer beam on yours looks neater than mine so I shall be stealing that idea as I still have two to do. I notice you have fitted a loop and dropper on the DG, I will be interested to see how much of the front end plumbing you can still fit on. One of the advantages of my fitting loops on both ends of my stock is that I don't have to fit any on locos and can also trim down the little wings of the buffing plate.

I'm not sure that mine is really any neater but thanks anyway. I think that mounting the buffer beam on the body does at least give you the choice of shaving some plastic from the cab front or the bottom of the buffer beam or doing both.

 

All of my stuff uses single ended DGs so all of my locos lack a certain amount of plumbing in the middle of the buffer beam - I usually need to stick to just the hoses or jumpers that are near to the buffers. On the positive side it eliminates the 'fighting loops' problem and also means that I only need to make half as many DG loops.

 

Regards, Andy

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Hello Andy, Jerry.

 

The Hymek looks much better lowered, I must pluck up the courage to do mine, particularly as it has a wonky buffer beam. One question though to both of you:  did you replace the wheels on your Hymeks or did you get them turned down? Is it easy to remove/replace them?

 

OK that's two questions.

 

Best

 

Peter

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Hi Peter,

 

The Hymek looks much better lowered, I must pluck up the courage to do mine, particularly as it has a wonky buffer beam. One question though to both of you:  did you replace the wheels on your Hymeks or did you get them turned down? Is it easy to remove/replace them?

The wheels were turned down by Gordon Solloway (i.e. the 2mm Association's wheel turning service).

 

Removing them is pretty straightforward. First pull the middle tank moulding off the chassis. Then turn the bogies through 90 degrees and they should drop out with no resistance.

 

The bogie is in two parts - the gear train/pivot and the sideframes/coupling. Unclip them from each other by pushing a screwdriver or fingernail down into the join at the back and then do the same at the front (i.e. between the gear train moulding and the coupling moulding. The wheels will stay with the sideframes but can now easily be sprung out and sent off to Gordon.

 

I did get asked recently by someone else with a Hymek whether I had a problem with the axles being too long over the pinpoints after turning but I did not have that problem.

 

Regards, Andy

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