Plastic horn blocks

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Andy W
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Plastic horn blocks

Postby Andy W » Mon Jan 13, 2014 9:38 pm

I'm always looking to simplify loco chassis building, I now build split chassis and am a convert to csbs. My next thought, especially as I'm looking at building a Brassmasters 0-4-0t with outside cylinders, was to use plastic horn blocks - and use the csbs to collect the current. That way the frames could remain neutral and the one piece frame spacer/cylinder fronts could be used as designed.

However, when I mentioned this cunning plan to a pal the other day (name withheld, but a well respected modeller) he winced. He was aware of Kean Maygib plastic horn blocks that had worn badly after some time, and resulted in bad running.

Has anyone else had experience with either KM or Exactoscale plastic horn blocks?
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MarkS
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Re: Plastic horn blocks

Postby MarkS » Mon Jan 13, 2014 9:58 pm

I have KM's only in tenders, so wear is less likely to be an issue, but,
how do propose to anchor your fulcrum points of your CSB's?
Typically they handrail knobs soldered to the chassis, or fold out tabs...
Cheers,

Mark.
"In the end, when all is said and done, more will have been said than done..."

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Andy W
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Re: Plastic horn blocks

Postby Andy W » Mon Jan 13, 2014 11:06 pm

Fold out tabs (probably LRM), or knobs, soldered to circuit board. The current will be wired from there to the motor.
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Tim V
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Re: Plastic horn blocks

Postby Tim V » Tue Jan 14, 2014 3:34 pm

The plastic hornguides I have seen were Maygib, is that what you were referring to?

Why do you think using insulated hornblocks would simplify things? You just solder the outside cylinders to their own PCB spacer , then cut through to insulate. Been doing it for years....
Tim V
(Not all railways in Somerset went to Dorset)

dal-t
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Re: Plastic horn blocks

Postby dal-t » Tue Jan 14, 2014 4:19 pm

Used to use Maygib as my 'standard' chassis construction, before I realised how easily they could bend, buckle and jam. I really would not recommend them to anyone ...
David L-T

Natalie Graham

Re: Plastic horn blocks

Postby Natalie Graham » Tue Jan 14, 2014 4:53 pm

Tim V wrote:The plastic hornguides I have seen were Maygib,


Exactoscale do plastic ones too.

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Tim V
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Re: Plastic horn blocks

Postby Tim V » Tue Jan 14, 2014 5:03 pm

I wasn't aware of those.

No change to my opinion though, briefly the Maygib ones were difficult to glue. I don't know how you would glue/rivet these Exactoscale ones, but any such work introduces potential variations in the wheelbase.

I was making the point previously - why complicate things? The key to reliable running is to have simple structures - less things to go wrong.

KISS :!:
Tim V
(Not all railways in Somerset went to Dorset)

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Andy W
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Re: Plastic horn blocks

Postby Andy W » Tue Jan 14, 2014 6:05 pm

"The key to reliable running is to have simple structures - less things to go wrong." I completely agree Tim. That's my philosophy as well. The spacer concerned is intricate - but maybe using PCB is the way. I was just musing as to a possible alternate approach.
Make Worcestershire great again.
Build a wall along the Herefordshire border and make them pay for it.

Natalie Graham

Re: Plastic horn blocks

Postby Natalie Graham » Tue Jan 14, 2014 6:34 pm

Tim V wrote:I wasn't aware of those.

No change to my opinion though, briefly the Maygib ones were difficult to glue. I don't know how you would glue/rivet these Exactoscale ones, but any such work introduces potential variations in the wheelbase.

I was making the point previously - why complicate things? The key to reliable running is to have simple structures - less things to go wrong.

KISS :!:


Just posting for information. I have never used them. I used the Maygib 2mm dia ones in 3mm Scale locos and my opinion is pretty much the same as yours. Hard to fit accurately and prone to drop off. I don't like pcb in chassis either though. It never seems to work for me and ends up falling apart with the copper peeling off the board although that might have been, at least in part, due to working in smaller scales and so using smaller bits of pcb. I haven't built any split axle chassis in P4 so far but my 3mm and 2mm efforts led me to use a bored out metal hornblock with an insulated bit of brass tube fitted in as a bearing bush. Leaving it protruding on the inside gives a handy place to connect the wires to the motor and you can solder up the rest of the chassis out of brass or n/s just as you would for one fitted with rim pick-ups.

Andy C

Re: Plastic horn blocks

Postby Andy C » Tue Jan 14, 2014 6:50 pm

I've used the Maygib variants on two locos. Like Tim V found, difficult to glue - in the end at the suggestion of Derek Evans I ended up tapping them and literally bolting them to the frames. They lasted a few years on Spotland Bridge and latterly the first couple of shows with New Hey before they ended up with loads of slop on the hornguides due to wear, and consequent running problems. Suffice to say they were not replaced with the same! As the saying goes it seemed like a good idea at the time.

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Tim V
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Re: Plastic horn blocks

Postby Tim V » Tue Jan 14, 2014 7:03 pm

Natalie Graham wrote: I don't like pcb in chassis either though. It never seems to work for me and ends up falling apart with the copper peeling off the board although that might have been, at least in part, due to working in smaller scales and so using smaller bits of pcb.

I can only assume you had the iron too hot, or left in place too long. I've successfully built 2mm split frame chassis using copper clad without those problems.
Tim V
(Not all railways in Somerset went to Dorset)

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Andy W
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Re: Plastic horn blocks

Postby Andy W » Tue Jan 14, 2014 7:50 pm

I'm not worried about fixing them - I'd use bolts and glue, belt and bracers. However, it's the wear and tear that concerns me. I much prefer to solder rather than glue, but I do like to try new techniques. The above postings though, have made me rethink and probably stick to metal horn blocks.

Thanks for the advice.
Make Worcestershire great again.
Build a wall along the Herefordshire border and make them pay for it.

billbedford

Re: Plastic horn blocks

Postby billbedford » Wed Jan 15, 2014 10:51 am

Natalie Graham wrote:
Tim V wrote:The plastic hornguides I have seen were Maygib,


Exactoscale do plastic ones too.


What these photos don't show is the springs that go with them. These are tiny curved strips of nylon that fit into the tops of the hornguides.


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