Sticking hornblocks: where to adjust?

Members Forum Kit Building Loco Chassis Sticking hornblocks: where to adjust?

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    • #244887
      Ben Weiner
      Participant

        Hi

        Here’s a novice question which I hope can be answered without difficulty. I have a set of MJT basic hornblocks (4003-4004) — from the Society stores as it happens. I’ve never built such things before. I folded one of the guides up (fold lines on inside or outside? this is not mentioned in the instruction sheet) and did a dry run slotting the tabs into the backing plate. Then I put in a bearing block. Given that it sticks and it shouldn’t, what should I be adjusting? My guess is the blocks shouldn’t be filed. Incidentally I tried another one with the fold lines the other way (so one with them inside, one outside) and my recollection is you could still just about get the tabs in the slots… but folding the piece back the other way again is terminal.

        Advice very welcome. Had I been able to get to the EMGS show at the weekend I would have asked a demonstrator!

        Thanks,

        Ben

      • #244947
        Trade Officer
        Keymaster

          You should file the guide and not the block. A few strokes of the file at a time. Make sure that  you keep track of which block fits into which slide.

          The usual rule is that the fold line goes on  the inside unless stated otherwise

          I will lookup the instructions that are supplied and check whether that is true for the guides

           

          John

        • #244949
          Ben Weiner
          Participant

            Many thanks, John!

             

            Ben

          • #244950
            Trade Officer
            Keymaster

              I forgot to say that it depends where it is sticking. If it is the tab that the slot slides in the the above is true. If it is the sliding surface than a few light strokes of the file on each side of the block should ease it. a little at a time!

              File flat on the table and run the side of the block along the file – not the other way round.

              Also run a small amount of solder into the bend after you have bent them

               

              John

            • #244952
              Stuart Firth
              Participant

                My experience of these is that they always stick solid when first tried. The first thing is that the slots the tabs go into are quite slim, so the act of pushing the tab into them can expand the metal slightly outwards. If it does then gently file it back straight. After this point I always adjust the block to fit the the guide – as John says, a few light strokes each side, then test, so on and so forth. It should be loose enough to fall under its own weight but not so loose that it can move back and forth. Finish with very fine wet and dry paper to get a really smooth finish. It’s very important to mark the bottom of the bearing with a scriber so you always put it back the same way, partly because once you start filing it the hole may no longer be perfectly central in the block, and partly because it sometimes isn’t anyway! If you always put it back in the same orientation then this doesn’t matter and will be taken into account when you install them using axle alignment jigs.

              • #244953
                Ben Weiner
                Participant

                  I’ll give this a go as soon as I get the chance. It goes without saying that this is a fundamental stage!

                  Thanks again
                  Ben

                • #245007
                  Paul Willis
                  Participant

                    Stuart’s advice is excellent.  If you follow this, and take it slowly with a little by little approach, you will get good results every time.  I’ve never used MJT hornblocks, as I find the High Level ones to be absolutely perfect.  But that is exactly what I do.

                    One other thing that hasn’t been mentioned is inherent from the guides being etched.  Sometimes there can be a “cusp” on the inside edges of the guide, as it is etched from both sides and can leave a ridge.  I don’t know if this occurs on the MJT guides.  If it does, the tiniest couple of strokes of a fine file will again leave a smooth running surface for the bearing.

                    Have fun!

                    Paul

                     

                    • #245009
                      Paul Tomlinson
                      Participant

                        Paul, your Y6 post in my “wants” ad. inspired me to make a start on mine. I’m using cast hornguides from London Road Models, and I thought I’d mention that I’m leaving the fettling-to-fit until after I’ve soldered them in, as I find a “sticky” hornblock makes it easier to handle them in the Poppy’s jig (which I find excellent). Back in the day, I had some plastic hornguides from Maygib, I think, which had a moulded rim to aid location in the cutout in the mainframe etch. You might just about be able to spot this in the photo below. Are there any like this (pref. metal) still available? Cheers.

                    • #245016
                      Ben Weiner
                      Participant
                        On Paul Willis said

                        Stuart’s advice is excellent.  If you follow this, and take it slowly with a little by little approach, you will get good results every time.

                        Again, much obliged!

                        Ben

                      • #245019
                        Paul Willis
                        Participant

                          Paul, your Y6 post in my “wants” ad. inspired me to make a start on mine. I’m using cast hornguides from London Road Models, and I thought I’d mention that I’m leaving the fettling-to-fit until after I’ve soldered them in, as I find a “sticky” hornblock makes it easier to handle them in the Poppy’s jig (which I find excellent).

                          That approach of not fettling until fitted is an interesting one, and not one I’ve ever followed.  The reason for that is once you’ve fixed your hornguides in the frames, the wheelbase is fixed.  If you then drift that wheelbase slight through the act of loosening up the axleboxes in the hornguides, the coupling rods may need to be adjusted to follow.

                          A jig, whether Poppy’s or Avonside (or even a one-off, as the 2FS folk tend to use) is an excellent idea, and will always result in an easier road to a smooth running chassis.  Having never used your build sequence, I don’t know if going from “stick” to “slide” will be a major change.  That said, if it works, it works!

                          Back in the day, I had some plastic hornguides from Maygib, I think, which had a moulded rim to aid location in the cutout in the mainframe etch. You might just about be able to spot this in the photo below. Are there any like this (pref. metal) still available?

                          I can’t stand those plastic hornblocks!  I still have some, in unmade Alan Gibson kits.  When I start the kits, I immediately put the untouched hornblocks on eBay!

                          To answer your question, I don’t know of any that now have a “frame” all the way around like those.  The High Level ones I use have a little tab to ensure that they are at the correct height in the frames.

                          But fore and aft on most hornblocks would be set by the jig.  Indeed, having a frame around like that may mean that it automatically builds in misalignment between the axleboxes and the coupling rods if there is no means of adjustment.  Like quite a few things still in railway modelling, it’s really a 1980’s product when 21st century tools and techniques have superseded it.

                          All the best with your build!  I’ll keep an eye on it, although I only pop in here every week or less.

                          Best,

                          Paul

                           

                        • #245058
                          Ben Weiner
                          Participant

                            Thanks all. That’s rather wonderful. Half nine isn’t the best time to go hammer and tongs at something like this, but with some very sparing filing on the sides  the bearing slid nicely between the ‘horns’, and with a minimum of filing with a number 4 on the sides of the channel in the back plate it moves freely up and down but without a chance of moving side-to-side.

                            So that seems like job done for the tutorial team. I admit to a profound dislike of two-component glue (partly because mixing it seems to be so wasteful) so the next step I have to do, following the instructions, will have a different risk of stickiness…

                            First I will look at putting some solder in the corners. What’s the expected travel of the bearing up the hornblock? Half way?

                            Sorry, that looks like more questions!

                            Ben

                          • #245059
                            Paul Willis
                            Participant

                              So that seems like job done for the tutorial team. I admit to a profound dislike of two-component glue (partly because mixing it seems to be so wasteful) so the next step I have to do, following the instructions, will have a different risk of stickiness…

                              Having just finished sticking some 4mm x 4mm x 4mm plasticard cubes on the end of a Ffestiniog Railway 009 dandy waggon, I hear your pain.  Araldite Rapid, mixed up in small amounts and applied to the cubes with the end of a cocktail stick.  Hopefully it will give that degree of robustness needed.

                              I’m building this for a friend, who isn’t confident of his soldering ability.  The dumb buffers are a customisation.  That said, having put it together, I described the kit to him as “unbuildable by following the instructions”, so I’m really glad that he didn’t even try it…

                              FR dandy waggon

                               

                              First I will look at putting some solder in the corners. What’s the expected travel of the bearing up the hornblock? Half way?

                              That is where bit of planning about the ride-height comes in.  Normally, you would expect to have the axle in the middle of the hornguide, vertically.  You only need about 0.5mm either way up and down.  If you need more than that, sort your track out first!

                              The actual adjustment to ride height can be made by adjusting a compensation beam up or down by bending it, or if you are using CSBs, using a different hole in the CSB carrier, or using a different gauge suspension wire for fine tuning.

                              Apologies if that sounds a bit vague.  Any picture of what you are working on?

                              Best,

                              Paul

                               

                            • #245060
                              Ben Weiner
                              Participant

                                Any picture of what you are working on?

                                J69 frames

                                It’s the frames for an Ian Rice J69 kit.

                                At some point I must have decided/understood that rigid frames and narrow tyre treads, especially with DCC, are for other people. I’ve got the order of march scrambled though because I have already added a couple of the frame stretchers but not cut out the openings for the hornblocks. So I will have to rewind a bit.

                                So – what happens to the etched springs? My feeling is cut them off and worry about them later. I value being able to drop out the axles, but as things stand I already have one fixed bearing for the rear axle. Should that come out and be replaced by a removable one?

                                Ben

                                • This reply was modified 1 year, 2 months ago by Ben Weiner.
                              • #245080
                                Paul Willis
                                Participant

                                  Ah, the Riceworks kit…  Very nice.  I keep promising myself one of those to build. But I have a couple of Connoisseur ones to build first.

                                  Now, being Iain Rice designed, then it is almost certainly designed for compensation.  That looks like the hole for the compensation beam axle between the LH and centre bearing holes.  But for compensation *or* CSB, you will need to remove that hornblock cut-out.

                                  I’d change it to CSB myself, but that’s because I’m a “convert” to springing and have no fears about doing it.  I’d split cahssis it at the same time, to help further with pick-up, like the 2FS boys do.

                                  To talk further about springs, removable fixed axles, and so on, a little more background would help.  Are you going to compensate or CSB it?

                                  And for the drop-out wheels question, what type (manufacturer) of wheels are you thinking of using?

                                  Best,

                                  Paul

                                   

                                • #245091
                                  Ben Weiner
                                  Participant

                                    To talk further about springs, removable fixed axles, and so on, a little more background would help. Are you going to compensate or CSB it?

                                    I have two fascinating Mike Sharman books I was given not so long ago but, but… I would like to see if I can achieve CSB. It looks as if it might be simpler. Is that reasonable? And yes there is provision for compensation and for CSB fixings. I think originally the chassis kit was accompanied by dedicated motorising and compensating kits.

                                    And for the drop-out wheels question, what type (manufacturer) of wheels are you thinking of using?

                                    Talking of Mike Sharman, he produced wheels suitable for this loco. I have a set bought at the same date as the kit (which is in its Iain Rice afterlife guise, from London Road Models) I had fairly strong recollections from my first round of EM in the early 1990s as a young teenager that Sharman wheels no longer existed at that date, but hey ho, seems they hung around a couple of decades longer.

                                    A consequence of this kit being produced by Iain Rice is having his writing style in the instructions. A classic line in the ‘erratum’ section: ‘One day I’ll get a kit 100% right – but until then – sorry!’

                                    Ben

                                  • #245109
                                    Paul Willis
                                    Participant

                                      Hi Ben,

                                       

                                      I personally find CSB to be simpler.  However, the kit that you have has been designed to be compensated, and you have started down that road.  So I suggest that you carry on through with the compensated route, and maybe consider CSB at some point in the future.

                                      If you have Sharman wheels, they will typically cope with being taken off the axles a couple of times before they lose their grip.  of course, after that you could rely on gluing and/or pinning the wheels on.  But again that is more complexity that is best avoided.  If you don’t have to take the wheels off at all after initial assembly (so don’t forget to paint the frames behind where the wheels will go first!) then you will have the most long-lived result.

                                      The Sharman wheel range did “disappear” for quite a few years, then went into the hands of Precision Paint who have rejuvenated it.  There is a limited range of wheels available through their website, and I have a smart new set of Y14 ones to go under a Gibson kit when I get around to it…

                                      I like the Riceism in the instructions.  Very typical, and heartwarming with it!

                                      Keep us posted on progress,

                                      Paul

                                       

                                       

                                    • #245111
                                      Stuart Firth
                                      Participant

                                        They are nice kits – I built this about 10 years ago for a friend.

                                         

                                      • #245114
                                        Ben Weiner
                                        Participant

                                          Thanks Paul and Stuart!

                                          I have to admit, I do find it difficult to think that the axles can never come out. I guess it is a matter of experience: if you build some loco kits competently and they run happily then you feel confident that generally there’s no need to remove them. I’m used to fiddling about with commercial chassis that may need a bit of help to run well, and the contacts are easier to keep clean and reposition if it’s possible to take all the wheels out once in a while. I often have secondhand stuff that is a bit battered and dirty so I am predisposed to think of the maintenance rather than the pristine new model (which of course may or may not run well). Indeed it’s part of the pleasure of the hobby for me to improve poor running.

                                          I can see that there are two things stopping me taking all the axles out. Firstly I’ve currently got a soldered bearing on the rear axle. Secondly, were that to be replaced by removable bearings, maybe a set of hornblocks where the vertical movement is prevented, the gearbox still has to be able to emerge from the underside of the frames, clearing the hornblock guides as it does so. It that the end of the story?

                                          Oh yes, and then there are those underhanging springs…

                                          Ben

                                        • #245115
                                          Stuart Firth
                                          Participant

                                            The way I see it is that as long as you are absolutely sure the motor/gearbox are running smoothly before you install them then the driving axle is unlikely to give you any trouble. If the gear wheel has a grubscrew fitting then the worse that’ll ever need to happen is you’ll have to remove one wheel to enable you to draw out the axle and free the gearbox. Re-fitting it may need Loctite though the tightness of fit of Gibsons varies enormously, from quite loose to needing a vice to put them on. I have had them off and on again occasionally on one or 2 loco’s and it’s never been terminal (yet!) Of course there’s always Markits…

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