Alan Gibson hornblocks and mainframes

[hayfield]

I recently bought a partially assembled Jedinco Beattie well tank, along with the awful Jedinco chassis, there was a strange whitemetal chassis with the wrong wheelbase but had a set of Romford wheels and mashima motor but thankfully a pair of Alan Gibson mainframes and an Alan Gibson hornblock set 

 

I am asking for any tips in the chassis construction please

 

I have a Hobby Holidays chassis jig and have used it twice to build rigid chassis, The AG instructions just tell you how to build the hornblock frames and casually say solder the frames into the milles slots in the frame

 

I assume after setting the jig up I solder in the first hornblock frame, then check if the second one fits, if not open up the mainframe slot then fit the second hornblock frame ?

 

Any advice/tips will be gratefully accepted

[Brassey]

Are you building this compensated or sprung?

[brossard]

ISTR trying Gibson hornblocks many years ago.  They are all soldered assembly and the very devil to work with.  I would recommend High Level hornblocks which are exquisite.

 

John

[Darwinian]

Gibson’s horn locks are OK in my experience but are designed to ride on the stops with the springs pushing the wheels down when the load comes off them. Unlike flexi-chas or CSBs. I think there have been several iterations over the years since they were first introduced.

[hayfield]

13 hours ago, Brassey said:

Are you building this compensated or sprung?

 

Sprung

 

13 hours ago, brossard said:

ISTR trying Gibson hornblocks many years ago.  They are all soldered assembly and the very devil to work with.  I would recommend High Level hornblocks which are exquisite.

 

John

 

I will check these out I also have several sets of Perseverance and MJT, possibly others as well

 

12 hours ago, Darwinian said:

Gibson’s horn locks are OK in my experience but are designed to ride on the stops with the springs pushing the wheels down when the load comes off them. Unlike flexi-chas or CSBs. I think there have been several iterations over the years since they were first introduced.

 

I thought they would be easier to fit into their own milled frames

 

 

[Brassey]

OK, As Gibson hornblocks (which I have never used) are sprung then we can assume the chassis is being built sprung which obviates the need for a fixed axle.

 

I too would support the previous endorsement of the High Level hornblocks as being exquisite though I am currently working on an Alan Gibson milled chassis using the MJT brass hornblocks.  No connection etc.

 

 

[Brassey]

In my experience there is a certain amount of tolerance in the 6mm cutouts of Gibson milled chassis that obviate the need for further fettling.  On the basis that the two sides are mirror images and if the first horn block goes in then the second should do also (assuming the frames have been assembled square).  

 

Another issue is whether the wheelbase for the rods are the same as as for the frames.  I have encountered this problem with LRM chassis where the rods were out thus making the hornblocks tight.

 

A further issue is getting the blighters soldered in square.  I too have a Hobby Holidays jig and use that combined with an engineers square to do this.  IIRC this may have been covered on the S4 Society Forum

Edited October 29, 2019 by Brassey
Typo

[hayfield]

55 minutes ago, Brassey said:

In my experience there is a certain amount of tolerance in the 6mm cutouts of Gibson milled chassis that obviate the need for further fettling.  On the basis that the two sides are mirror images and if the first horn block goes in then the second should do also (assuming the frames have been assembled square).  

 

Another issue is whether the wheelbase for the rods are the same as as for the frames.  I have encountered this problem with LRM chassis where the rods were out thus making the hornblocks tight.

 

A further issue is getting the blighters soldered in square.  I too have a Hobby Holidays jig and use that combined with an engineers square to do this.  IIRC this may have been covered on the S4 Society Forum

 

Thanks for the advice, one negative is that Alan Gibson do not do 7' 4 coupled rods, I do have a set which are un-named which saves me making a set up from a universal pack

 

Thanks for the tip about getting them square, I saw the tutorial on Youtube by Derek of Elaine's Emporium where he used an engineers square 

[hayfield]

1 hour ago, Brassey said:

OK, As Gibson hornblocks (which I have never used) are sprung then we can assume the chassis is being built sprung which obviates the need for a fixed axle.

 

I too would support the previous endorsement of the High Level hornblocks as being exquisite though I am currently working on an Alan Gibson milled chassis using the MJT brass hornblocks.  No connection etc.

 

 

 

Thanks I will have a chat with Chris, as I said I have some MJT hornblocks, any benefits of using these in preference?

[PenrithBeacon]

2 hours ago, hayfield said:

 

Thanks I will have a chat with Chris, as I said I have some MJT hornblocks, any benefits of using these in preference?

MJT hornblocks are fine but you need to cut a 'finger' in the side frame to accommodate the spring.

Cheers

[hayfield]

Just to show you the rag tag bundle of chassis that were in the lot in addition to the loco, frames and hornblocks

 

 

To recap there was a partly and badly built Jedinco Beattie Well Tank loco. as I said a set of Alan Gibson Mainframes and hornblocks. Obviously the builder gave up on the Jedinco chassis and there was a cast chassis, which has a set of Romford drivers and a Mashima motor

 

The loco body is in need of a complete rebuild, I paid just over £38 inc postage, my worst case scenario (providing the motor works is that I have a motor which would cost me £24, a set of wheels £30, new style gears £5, set of Gibson frames, coupling rods and hornblocks  £29. So at new prices £88 all of which could either be used or resold, if the loco is buildable its a bonus

 

As it happens the cast chassis has an 8' wheelbase and 20 mm wheels. I need a 7' wheelbase and 22mm wheels. The motor works but the home made motor mount is useless. So I am thinking I have a free shot at building an Alan Gibson sprung chassis  

[Brassey]

2 hours ago, hayfield said:

 

Thanks I will have a chat with Chris, as I said I have some MJT hornblocks, any benefits of using these in preference?

 

I tend to use the MJT Hornblocks with brass chassis and High Level in Nickel and there is no other justification for the preference.  As previously alluded to though, one advantage of the High Level version is that soldering is not necessary in preparation although I do add a touch.

 

I have used the Comet and Brassmasters sprung hornblox in sprung chassis and will use the system supplied with the Finney kits in those chassis.

 

One element of the Hobby Holidays jig and other similar systems is that it is intended that the rods are used to initially set the jig up before fitting the hornblox.  To proceed without this would be a leap of faith that the rods afterwards would fit without binding.  I have done this once with Comet chassis in the trust that the frames and rods were on the same fret.  However, if the rods are from different suppliers, then the likliehood of a mismatch are greater.

[PenrithBeacon]

1 hour ago, hayfield said:

Just to show you the rag tag bundle of chassis that were in the lot in addition to the loco, frames and hornblocks

 

 

...

I can't see any hornblocks in that photo.

 

I have in my stash a Kernow RTR Well Tank with the intention of replacing the RTR chassis with AGW chassis components but I think I might use High Level hornblocks, they're by far the best.

 

Cheers

[hayfield]

1 hour ago, PenrithBeacon said:

I can't see any hornblocks in that photo.

 

I have in my stash a Kernow RTR Well Tank with the intention of replacing the RTR chassis with AGW chassis components but I think I might use High Level hornblocks, they're by far the best.

 

Cheers

 

David

 

Neither can you see the Gibson Frames and set of universal coupling rods

 

You are the second person to recommend High Level Hornblocks, must have a chat with Chris

Edited October 29, 2019 by hayfield

[MikeTrice]

Another benefit of the High Level Hornblocks is they fold up without needing soldering which can make soldering to the frames easier.

[hayfield]

1 hour ago, Brassey said:

 

I tend to use the MJT Hornblocks with brass chassis and High Level in Nickel and there is no other justification for the preference.  As previously alluded to though, one advantage of the High Level version is that soldering is not necessary in preparation although I do add a touch.

 

I have used the Comet and Brassmasters sprung hornblox in sprung chassis and will use the system supplied with the Finney kits in those chassis.

 

One element of the Hobby Holidays jig and other similar systems is that it is intended that the rods are used to initially set the jig up before fitting the hornblox.  To proceed without this would be a leap of faith that the rods afterwards would fit without binding.  I have done this once with Comet chassis in the trust that the frames and rods were on the same fret.  However, if the rods are from different suppliers, then the likliehood of a mismatch are greater.

 

 

Brassey

 

Thanks for the advice, my thought was to set the Hobby Holidays jig up with the coupling rods, solder the first hornblock in place then use the jig to set the second set up, using a square both times.

[hayfield]

Well I have taken the plunge

 

 

This is a dry run, I tried my best to use the chassis building jig, but it was far easier to di it free hand on the workbench as the milled cutouts seemed to fit the coupling rods fine. Used 21 mm (instead of 22 mm) Romford wheels as the flanges are a bit on the large side. not decided on motor or gearbox. This is a bit of a test bed, I have built an equalised chassis many years ago, but never a sprung one before. Using Romford wheels will allow me to take the wheels on and off whilst trying things

 

 

As I said its a dry run, I have yet to fit the springs and retaining wires in each hornblocks, neither have I tried the coupling rods but the chassis runs freely. It will go under a Jedinco part built kit I bought, what has stayed in place will have to be rebuilt as its a mess, but was very cheap and worth the gamble.

 

Still next up is forming the guide/retaining wires and springs

[hayfield]

One step forward and about 3 back

 

 

It took me ages to get the first hornblock fitted but go easier with each one. Trouble is the springs seem too strong, wheels are all over the place quartering is now out and definitely lost its free running charistics

 

I will take the chassis back to its state last night, where it was free running, Firstly see if the quartering is OK. Then figure out the springing again.

[KalKat]

Surely being Romford/Markits, they can't be out of quarter? The error is more likely to be in the rods or there is a dimension error twixt rods and hornblock position

 

 

Emma

[hayfield]

36 minutes ago, KalKat said:

Surely being Romford/Markits, they can't be out of quarter? The error is more likely to be in the rods or there is a dimension error twixt rods and hornblock position

 

 

Emma

 

 

I was struggling fitting the hornblock guides in the chassis jig as it was acting as a heat sink. I fitted them free hand and all seemed OK, I will need to reset them again. One of the front horn guides also seems out of square. Just a new learning curve for me

[shellshock]

If the springs seem too strong try Alan Gibson Buffer Springs in Phosphor Bronze if memory serves me. Use the adjusting screws so that it rides on the stops with the springs pushing the wheels down when the load comes off them.

[hayfield]

Thanks for that advice, will bear it in mind

 

A couple of things, the first being I filed to file a notch in the top of the bearings for the springs to sit in, secondly as there is no motor or body on the chassis the springs are too strong for the chassis as its too light to ride on the stops

 

The main thing is the hornguides may need adjusting. I need to go back a few steps and re-check the squareness as I think this may be the issue

[MikeTrice]

Another possibility lies with the wheels. From memory early Romfords were not predrilled for the crankpins. Given you do not know the age of the Romford drivers there is no guarantee they are drilled accurately

[cctransuk]

1 hour ago, hayfield said:

 

 

I was struggling fitting the hornblock guides in the chassis jig as it was acting as a heat sink. I fitted them free hand and all seemed OK, I will need to reset them again. One of the front horn guides also seems out of square. Just a new learning curve for me

 

All this 'floppy chassis' business seems to me to be making trouble for oneself; I'm with Tony Wright on this - give me a good old rigid chassis any time.

 

(..... and, yes - I have built compensated and sprung chassis, but they were a lot more faff and didn't run as well as my rigid ones).

 

Regards,

John Isherwood.

[Andy Reichert]

 

Work in progress, 4mm experimental rigid side frame with built in full suspension, but no horn blocks.

 

Andy

Edited November 14, 2019 by Andy Reichert
messed up image first time