Yorkshire Dave
Western Thunderer
Interesting - sounds like it's the motor rather than the decoder. Was the original Maxon motor supplied a 12-18v motor? Does it run hot when tested on analogue? - if so then there is something wrong with the motor.
7mm Mickoo's Commercial Workbench
- Thread starter mickoo
- Start date
Interesting - sounds like it's the motor rather than the decoder. Was the original Maxon motor supplied a 12-18v motor? Does it run hot when tested on analogue? - if so then there is something wrong with the motor.
mickoo
Western Thunderer
Quick DA Jubilee update, getting there slowly.
The cab is a bit of a mare, no slots or tabs or easy fold front/sides, three pieces all floating where they want on the wind. The cab floor is a nice fold up box but is to narrow so can't be used as a spacer unless you pack it out. I made a jig using the cab front as a template and got there in the end.
Mind I do need to sort the cab roof/eaves at the rear on the RH side, just needs a tweak to level it up. Strangely it doesn't look nearly as bad in real life as in the photo, the wide angle lens is exaggerating the fault a little.
The only other niggle was the middle cylinder cover, it's too narrow to fit between the frames above the footplate at the front by about 0.5 mm. I grafted a piece of plate on one side and then cleaned it up to match the profile, it'd have been just as easy to mark out and fold up a new one I suppose.
None of the motion or cylinders are screwed down so are a bit on the wonk in relation to the footplate.
The cab is a bit of a mare, no slots or tabs or easy fold front/sides, three pieces all floating where they want on the wind. The cab floor is a nice fold up box but is to narrow so can't be used as a spacer unless you pack it out. I made a jig using the cab front as a template and got there in the end.
Mind I do need to sort the cab roof/eaves at the rear on the RH side, just needs a tweak to level it up. Strangely it doesn't look nearly as bad in real life as in the photo, the wide angle lens is exaggerating the fault a little.
The only other niggle was the middle cylinder cover, it's too narrow to fit between the frames above the footplate at the front by about 0.5 mm. I grafted a piece of plate on one side and then cleaned it up to match the profile, it'd have been just as easy to mark out and fold up a new one I suppose.
None of the motion or cylinders are screwed down so are a bit on the wonk in relation to the footplate.
mickoo
Western Thunderer
And where's the fun in that
I actually cut two lengths of 2mm NS rod the same width as the cab front and tack soldered longitudinally across the footplate with the same gap each side, one at the front of the cab where the footplate sweeps up and one at the rear. Then I tacked the cab sides in place, fitted the front, removed the spacer rods and seam soldered the sides to the footplate.
I've just dropped them back in for the photo as the cab floor isn't fitted yet. I also changed the rear fixings which where two 6BA screws sticking down, the one on the rear right is fine as the cab step hides the thread and nut, but the one on the left is further forward by about 8 mm (no idea why
) and fully visible in front of the cab steps. I fitted two 8BA nuts to the floor and drilled corresponding holes in the chassis for two screws hidden between the frames.
Brian McKenzie
Western Thunderer
Nice job on fixing the cab.
Mick, to correct a situation like this, could you offer some direction on artwork? If a U shaped foldup was required to measure e.g. 50mm externally after foldup, in say 0.45mm thick half-etched metal, what line width and spacing of lines ought to be used?
This is just curiosity on my part. Have been deeply 'V' scoring 0.3mm brass, to get sharp external corners, but despite the simple geometries involved, it has not been easy to achieve multiple parts consistently with the desired folded-up width.
mickoo
Western Thunderer
Cheers,
Ah, now there lines a can of wriggly things and tough to answer.
The width of your folds are important, typically the same width as the material thickness but often people add 10-20%, that's where things start to get messy. If you draw to 100% and the etchers over cook then your slot will be too wide and sloppy, if they under etch it won't fold 90° neatly; if you increase by 10% and they over etch the slot is massive and the bend may not be in the middle of the slot or parallel along it's length, if they under etch then it'll be perfect. That (over/under etch) happens all the time but rule of thumb I add 5-10% and wing it.
If you need something close to (I'm not saying exactly as that's almost impossible to achieve if you take the last paragraph into context) 50 mm overall width in 0.5 mm, then your middle piece will be 50 mm wide, minus two 0.5 mm slots deducted on the inner side of each bend. Your fold 'corners' should form in the middle of the 0.5 mm slot, ergo 0.25 mm from each side.
I did some notes and drawings on here a few years ago, can't find them now, but briefly something like this.
The important bit is the bend, the red hatched area actually stretches the metal, the red dots fold and end up touching each other so the fold up thickness becomes part of the overall width. The stretching is why you can never get a crisp corner with etched sheet work, you can get close by deepening the etched slot with a V file but the outer skin will always stretch and leave a radius on the outer surface.
Where it gets difficult is if you increase your slot size to give you more bend room, if you increase from 0.5 to say 0.6 then it must be 0.05 each side, not 0.1 on the inside or outside edge. The easiest way is to draw the slot to material thickness like the drawing and then widen each side uniformly.
Of course this is all theory and etching is like witch craft, so none of this can be applied in a real world consistently, it just depends how accurately you want it to be. It's not unusual for several parts that fold up on several sheets and be 0.1-0.15 different over their width. If you want consistencey then best put all those critical parts on the same sheet, that way if they're over/under etched it affects all the parts uniformly.
Brian McKenzie
Western Thunderer
Thanks Mick, for the explanation and effort you have gone to there.
Aside from the issue of getting the same as-folded measurement repeatedly (for cosmetic matching rather than 'accuracy'), the crispness of the outer corners is looking good. Scoring is continued until this impression appears on the underside:
Any more, then it starts splitting apart (did so once - it got converted into a roughly welded repair
).
Aside from the issue of getting the same as-folded measurement repeatedly (for cosmetic matching rather than 'accuracy'), the crispness of the outer corners is looking good. Scoring is continued until this impression appears on the underside:
Any more, then it starts splitting apart (did so once - it got converted into a roughly welded repair
).
mickoo
Western Thunderer
I’ve often done that too with etches if I want a crisp corner, I use a Tamiya skrawker until I see the witness line on the outside and then fold.Thanks Mick, for the explanation and effort you have gone to there.
Aside from the issue of getting the same as-folded measurement repeatedly (for cosmetic matching rather than 'accuracy'), the crispness of the outer corners is looking good. Scoring is continued until this impression appears on the underside:
View attachment 199408
Any more, then it starts splitting apart (did so once - it got converted into a roughly welded repair
You only get one chance as any further folding runs the risk of splitting the joint. Then I generously back fill with high temp solder to give it strength.
Hand cutting joints is different to etched joints and is down to where you make your cut, plus the cut is generally a V as opposed to a trough so the metal behaves differently. If I had to hand cut the joints I’d skrawk my bends at 49.5 apart and the fold should come out at 50 mm overall in 0.5 mm material.
It does also depend on how deep you cut and in theory the cuts should be near 50 mm apart but you need to leave some tolerance for the bit that stretches on the outer surface and pushes the sides a bit further apart. Basically the deeper the cut the closer to 50 mm apart you can make your cuts. No cut and your bend lines would be 49 mm apart, probably less as the inside surface bend is never a sharp 90 degree bend, it always has a radius which is why we etch troughs and cut Vs.
Big Train James
Western Thunderer
Aside from the issue of getting the same as-folded measurement repeatedly (for cosmetic matching rather than 'accuracy'), the crispness of the outer corners is looking good. Scoring is continued until this impression appears on the underside:......
.......Any more, then it starts splitting apart (did so once - it got converted into a roughly welded repair
I'm somewhat surprised that you aren't machining your scored grooves with something like a chamfer cutting end mill. It sounds a bit silly maybe, but not necessarily if you have the tools and skills as you do. Of course you need to set it all up, but after that accuracy and repeatability should be obtainable. You also get the piece of mind of knowing that you aren't going to blow all the way through the material. All of the above is predicated on the idea that the sheet material is consistent in thickness.
Brian McKenzie
Western Thunderer
Thanks guys, I have what I need now. The amount of stretch occurring in some folds was surprising (up to 0.5mm overall when adding up the external measurements of two folded sides plus the end), despite getting fairly crisp outer corners in the 0.012" brass used (from 6" x 18" Flat Sheets - Precision Brand a supplier very near to Jim).
The lack of repeating precision, I put down to some variation in the scoring by hand, despite using steel blocks temporarily glued on to guide the skrawker. If every doing this again, I'll use a shaped lathe tool set up to plane the grooves. An engraving tool rotating perpendicular to the brass wasn't good for achieving a sharp corner.
The lack of repeating precision, I put down to some variation in the scoring by hand, despite using steel blocks temporarily glued on to guide the skrawker. If every doing this again, I'll use a shaped lathe tool set up to plane the grooves. An engraving tool rotating perpendicular to the brass wasn't good for achieving a sharp corner.
mickoo
Western Thunderer
Slow week at the bench this week, children, horses, A&E, trauma unit, driving 300 mile round trips, blah blah blah....sign. I'd hoped to be wrapped up by now but family comes first 
The cylinder block and motion bracket assembly is not bolted down, neither is the body, so some odd angles between the two which'll all straighten out in the end.
Of the three days I did get in, the firebox took almost two. I binned the kit wrapper, hopeless trying to bend 0.4 mm around that and it barely fitted. I'm sure it can be made to form the right shape and possibly made to fit, but I was feeling fatigued and lazy so made a new one.
Out went the 2D half etched washout plugs, they're being replaced with 3D ones that have a coned recess and plugs, they're rather wee but look the part when fitted; only the two front boiler ones fitted so far. Other than a new 3D smoke box saddle the rest is out of the box.
The cylinder block and motion bracket assembly is not bolted down, neither is the body, so some odd angles between the two which'll all straighten out in the end.
Of the three days I did get in, the firebox took almost two. I binned the kit wrapper, hopeless trying to bend 0.4 mm around that and it barely fitted. I'm sure it can be made to form the right shape and possibly made to fit, but I was feeling fatigued and lazy so made a new one.
Out went the 2D half etched washout plugs, they're being replaced with 3D ones that have a coned recess and plugs, they're rather wee but look the part when fitted; only the two front boiler ones fitted so far. Other than a new 3D smoke box saddle the rest is out of the box.
mickoo
Western Thunderer
Appreciated, she's back home now and resting. They wouldn't release her from Oxford until I sent the wife a picture of her bed I had to move downstairs; she's there for a couple of weeks at least. Luckily we have downstairs amenities or else she would have been transferred to Ipswich or Norwich hospital in an ambulance.
Fortunately it was a clean break mid shaft, so a titanium rod top to bottom down the middle of the bone with securing screws; all done through key hole surgery so only two scars about an inch long at the hip and just above the knee.
mickoo
Western Thunderer
That's better, quick test run of the revised Slaters SG39 motor/gearbox combo they're now producing.
I've not mapped the motor for DCC yet (parameters are still for the previous ABC+10W Maxon) so it's still got a little bit of whine to it and the gears are a bit ticky as it hasn't been run in yet.
But for out of the box performance it's looking good. It'll get a nice long run in now to settle everything and make sure no crankpin nuts drop off
, then I'll add the weighted body and map the motor with tender connected as a final set up.
Please use the 4K option for best quality.
I've not mapped the motor for DCC yet (parameters are still for the previous ABC+10W Maxon) so it's still got a little bit of whine to it and the gears are a bit ticky as it hasn't been run in yet.
But for out of the box performance it's looking good. It'll get a nice long run in now to settle everything and make sure no crankpin nuts drop off
, then I'll add the weighted body and map the motor with tender connected as a final set up.Please use the 4K option for best quality.
mickoo
Western Thunderer
Another one done and dusted....so I thought.
Some bits, injectors, cinder shield frames (new etches) and back head still need to be added after paint; but, before that I need to fit the whistle and I'll add a smoke box door number plate bracket with stand offs before strip down.
Next up Precursor frame etches and a pile of sundry items for bespoke parts for folks to fill any gaps. Then onto (tender already started) a Gladiator ROD 04.
Forgot to say, the screw on the eccentric rod big end will get replaced with a smooth top 12BA screw on the final build, just easier to fit a 12BA slotted screw here for the build process/testing and strip down.
Some bits, injectors, cinder shield frames (new etches) and back head still need to be added after paint; but, before that I need to fit the whistle and I'll add a smoke box door number plate bracket with stand offs before strip down.
Next up Precursor frame etches and a pile of sundry items for bespoke parts for folks to fill any gaps. Then onto (tender already started) a Gladiator ROD 04.
Forgot to say, the screw on the eccentric rod big end will get replaced with a smooth top 12BA screw on the final build, just easier to fit a 12BA slotted screw here for the build process/testing and strip down.
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michael mott
Western Thunderer
It is always such a pleasure to see your work Mick, the quality is outstanding!
Michael
Michael
OzzyO
Western Thunderer
Hello Mick,
Most L.M.S. locos didn't have straps for the number plates to fit on. The smokebox number plate was cast to fit the smokebox door. I've got some drawing for them in one of the Jenkinson books. In these two photos the first one you can see the shadow from the number plate. In the second one you can see that it's a solid plate.
ATB
OzzyO.
Most L.M.S. locos didn't have straps for the number plates to fit on. The smokebox number plate was cast to fit the smokebox door. I've got some drawing for them in one of the Jenkinson books. In these two photos the first one you can see the shadow from the number plate. In the second one you can see that it's a solid plate.
ATB
OzzyO.