Search found 128 matches

by davebradwell
Thu Jan 23, 2020 5:48 pm
Forum: Steam Locomotives
Topic: Martin Finney V2
Replies: 10
Views: 285

Re: Martin Finney V2

I think the 2-6-* is the worst arrangement for clearances - my K1 took careful design but I was ahead of the game on the V3. Didn't the GW use wider cylinders but this just allowed them to put a boss on the wheels. I've always just held the whole wheel by the flange in soft jaws and skimmed 6 thou' ...
by davebradwell
Thu Jan 23, 2020 9:40 am
Forum: Steam Locomotives
Topic: Martin Finney V2
Replies: 10
Views: 285

Re: Martin Finney V2

Yes, you'll need to file faces of wheels flush with tyres. They'll still be wider than scale but should fit. You can skim wheels down to the scale 1.85 thickness too if you have the facilities (front flange on tyre should be thick enough - it's usually 0.3) and any of these changes mean you have to ...
by davebradwell
Wed Jan 22, 2020 9:13 am
Forum: Coaches and NPCS
Topic: Converting Hornby Collett Non Corridor Stock to P4
Replies: 21
Views: 735

Re: Converting Hornby Collett Non Corridor Stock to P4

1 in 300 is 0.13mm (5 thou') out of flat on a 10ft w/b vehicle; a bogie coach should cope with 0.6 tilt between bogies - so a 10ft vehicle should just about be able to bump over a typical piece of half etched brass. That seems rather too easy but I suspect the test track in question demands signific...
by davebradwell
Tue Jan 21, 2020 6:04 pm
Forum: Coaches and NPCS
Topic: Converting Hornby Collett Non Corridor Stock to P4
Replies: 21
Views: 735

Re: Converting Hornby Collett Non Corridor Stock to P4

I think you're walking into a conundrum here in that if you can measure your track defects accurately in order to declare it's all in spec then you are probably quite able to lay decent track in the first place. Track should be as good as you can get it and if you find a step then why not fix it. It...
by davebradwell
Sat Jan 18, 2020 5:55 pm
Forum: Tools and Techniques
Topic: Wheels for Peckett B2 conversion (and others)
Replies: 13
Views: 869

Re: Wheels for Peckett B2 conversion (and others)

I've always thought the Barclay a missed opportunity due to the lack of daylight under the boiler but looking at you pictures do you think it might it be possible for me to cut through and correct this if I bought one or are there vital organs contained therein? I see there could be an odd gear near...
by davebradwell
Fri Jan 17, 2020 11:08 am
Forum: Coaches and NPCS
Topic: Bill Bedford Coach Bogies
Replies: 17
Views: 783

Re: Bill Bedford Coach Bogies

I don't get the wire problem. Don't you just hold the bit of curved wire in a pair of pliers and stroke between thumb and forefinger? Sometimes it curves the other way but just try again. I can straighten a lot of wire by the time you've sourced your guitar string. It's #2 music wire for AJs, Julian...
by davebradwell
Thu Jan 16, 2020 10:49 am
Forum: Coaches and NPCS
Topic: Thompson BZ 6 wheel van
Replies: 15
Views: 2512

Re: Thompson BZ 6 wheel van

I prepared a comprehensive reply, Julian, but it disappeared and I can't face repeating it. Essentially I suggest that the springs for your centre axle are too close together so the unit tries to tip rather than slide. It's the same with Cartazzis. Also I can't understand what the central piece of w...
by davebradwell
Thu Jan 09, 2020 8:37 pm
Forum: Coaches and NPCS
Topic: Thompson BZ 6 wheel van
Replies: 15
Views: 2512

Re: Thompson BZ 6 wheel van

Ah, but will your Jackson uncouple on a magnet, Julian? Almost anyone can make one that "ties on" but uncoupling in a proper manner is the clever bit.

DaveB
by davebradwell
Mon Dec 16, 2019 10:11 am
Forum: Starting in P4
Topic: 4 wheel wagons rigid or non-rigid chassis?
Replies: 12
Views: 671

Re: 4 wheel wagons rigid or non-rigid chassis?

I agree but do run an embarrassing number of r-t-r wagons with just the wheels swapped for P4, although a little slogger in the bearings helps the things adapt to small track imperfections. Many of these are 12ft wheelbase hoppers which is pushing my luck but I suggest you don't risk longer wheelbas...
by davebradwell
Sat Dec 07, 2019 5:08 pm
Forum: Steam Locomotives
Topic: Jig for drilling crankpin hole
Replies: 72
Views: 2895

Re: Jig for drilling crankpin hole

My warning about not milling in a drill didn't go very far then - please check with Proxxon first that the bearing are up to it.

DaveB
by davebradwell
Fri Dec 06, 2019 7:34 pm
Forum: Steam Locomotives
Topic: Jig for drilling crankpin hole
Replies: 72
Views: 2895

Re: Jig for drilling crankpin hole

Tim, I added the warning re milling because there was talk of using a co-ordinate table so it would be tempting. Slow wheel feed would just be a nuisance.

"Outside the asylum" reference to lighten a dark hour on this thread.

DaveB
by davebradwell
Fri Dec 06, 2019 7:19 pm
Forum: Steam Locomotives
Topic: Jig for drilling crankpin hole
Replies: 72
Views: 2895

Re: Jig for drilling crankpin hole

You should be very careful milling in a drilling machine as the bearings are lighter and not designed to take a side load. Suggest check with Proxxon first. Also the chuck is usually just mounted on a taper so when milling is liable to come off which might be exciting at 8,500 rpm. There is a body o...
by davebradwell
Fri Dec 06, 2019 3:02 pm
Forum: Steam Locomotives
Topic: Jig for drilling crankpin hole
Replies: 72
Views: 2895

Re: Jig for drilling crankpin hole

That looks just the job, Tim, although you'd get more secure clamping by just putting a toolmakers' clamp over the lot instead of your little screw. As it's made of brass suggest drilling by hand with the largest tapping drill you dare - as Julian says it goes through the plastic easily. Julian's ve...
by davebradwell
Fri Dec 06, 2019 10:51 am
Forum: Steam Locomotives
Topic: Jig for drilling crankpin hole
Replies: 72
Views: 2895

Re: Jig for drilling crankpin hole

Early on in the thread somebody had used a friends drill which seems a good solution. I think Julian's original brass jig would work as well as one drilled into a solid block and suggested ensuring a tight fitting tube. Don't know why he went off in a different direction. It's an inescapable fact th...
by davebradwell
Thu Dec 05, 2019 6:14 pm
Forum: Track and Turnouts
Topic: Exactoscale Fastrack
Replies: 7
Views: 596

Re: Exactoscale Fastrack

Stick it down with the ties in place then cut them out with a pointy scalpel when the glue's dried.

DaveB
by davebradwell
Thu Dec 05, 2019 6:11 pm
Forum: Steam Locomotives
Topic: Jig for drilling crankpin hole
Replies: 72
Views: 2895

Re: Jig for drilling crankpin hole

Some very fine procedures have been described, although no-one has put wheels on pin on lathe faceplate. Drilling machine and 1/8" pin to locate wheel probably simplest and most versatile. One troubling thought - there's been no mention of starting holes with a centre drill. Possibly just folk ...
by davebradwell
Wed Dec 04, 2019 2:46 pm
Forum: Steam Locomotives
Topic: Jig for drilling crankpin hole
Replies: 72
Views: 2895

Re: Jig for drilling crankpin hole

I'm lost here - why was there support for drilling from the back when suddenly all are showing ways of drilling from the front? I'd screwed up my logic, too so will repeat that the most certain way is to make simple jig from a piece of bar to locate in axle hole and with locating hole for crankpin. ...
by davebradwell
Wed Dec 04, 2019 12:21 pm
Forum: Steam Locomotives
Topic: Brassmasters Blk5 45232
Replies: 51
Views: 4755

Re: Brassmasters Blk5 45232

Dave, I've been using lace pins to assemble forked valve gear for years now. These have a bulge behind the point which should be cut off and very slight long taper towards the head so with great care it's possible to broach holes and achieve press fits so no solder. After cutting off excess pin from...
by davebradwell
Wed Dec 04, 2019 11:59 am
Forum: Steam Locomotives
Topic: Jig for drilling crankpin hole
Replies: 72
Views: 2895

Re: Jig for drilling crankpin hole

Can we just agree that, well it's not sensible to drill from the back of the wheel if all crank throws are to have a chance of being similar. If the drill comes out off-piste then straightening it is just going to produce a straight crankpin in the wrong place. A small pip in soft abs isn't going to...
by davebradwell
Fri Nov 29, 2019 10:57 am
Forum: Starting in P4
Topic: Making a Start - The Peak District Midland / Monsal Dale pre 1903
Replies: 1103
Views: 152046

Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Can I suggest, DougN, that if your nuts are falling off you check that there is visible sideplay of the rods on the crankpins and particularly on curves. At least your nail varnish doesn't migrate like Loctite but shellac would be more in keeping and similarly loosened with the appropriate solvent. ...
by davebradwell
Thu Nov 28, 2019 8:58 pm
Forum: Starting in P4
Topic: Making a Start - The Peak District Midland / Monsal Dale pre 1903
Replies: 1103
Views: 152046

Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Yes, it would be standard practice to use a locking washer on a screwed fastener but in my recollection where I worked, we only became obsessive about this when jets took over airfreight- just a little before my time but remembered by my mentors. By mimicking the high frequencies of these engines on...
by davebradwell
Thu Nov 28, 2019 8:40 pm
Forum: PeteT
Topic: J39 64859 Bachmann/Dave Bradwell
Replies: 12
Views: 898

Re: J39 64859 Bachmann/Dave Bradwell

Yes, I gave up investigating my tender dome and eventually put it on just to check if would fit. I have seen a photo of a Carlisle J39 going over the HL bridge and taken from above which showed plated over dome but the traditional photo viewpoint isn't helpful here. I suspect J39 tenders need a 10 v...
by davebradwell
Thu Nov 28, 2019 7:15 pm
Forum: Starting in P4
Topic: Making a Start - The Peak District Midland / Monsal Dale pre 1903
Replies: 1103
Views: 152046

Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

On the other hand you could not put any locking compound on and they still won't come off - unless they're gripping the rods, probably on curves. I'm sure I've never ever had one unscrew - I have an aversion from my professional days to putting locking stuff anywhere near precision mechanisms as it ...
by davebradwell
Thu Nov 28, 2019 7:03 pm
Forum: PeteT
Topic: J39 64859 Bachmann/Dave Bradwell
Replies: 12
Views: 898

Re: J39 64859 Bachmann/Dave Bradwell

This was a surprise as I always check the fit of parts before releasing kit. However, after investigating, I do need to own up to a number of small errors and I apologise for not spotting them before release. I haven't looked in the instructions where I sometimes confess my sins. The first of these ...
by davebradwell
Thu Nov 28, 2019 5:47 pm
Forum: PeteT
Topic: J39 64859 Bachmann/Dave Bradwell
Replies: 12
Views: 898

Re: J39 64859 Bachmann/Dave Bradwell

Short hangers are the right ones. Hang on a bit longer and I'll post results later this eve.

DaveB

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