Broad Ambition - The Model

[ranworthbreeze]

13 hours ago, grendel said:

reprinted the roof vents in black, chromed they look a lot better as the black just shows as shadow, today i also printed out some new interior lights.

Hi Grendel,

My first thoughts were why you had taken the picture with a few Fruit  Pastels in the shot

Regards

Alan

[grendel]

Alan, they are about half the size of a fruit pastel, and are the 'clear' centres for the vents.

[ExSurveyor]

Peter, what did you do for this type of thing before 3D printing, ?

[grendel]

you can buy these as a cast resin part, or you would find something suitable you could modify with modelling putty, or make a mould and former and stamp them from thin metal sheet (or indeed turn them up on a lathe) for me, owning the printer and having the CAD skills, 3d printing is just another tool (and saves me having to go out and buy something made by someone else.)

[RumPunch]

Yeah - I'd have resort to making one and having to resin cast the rest. Agree on the Moltow pens being great BTW - use them a lot in my plastic modelling

[grendel]

Well today was working on cleats day, on model #1 i made these from brass rod and tube soldered together, this time i had an idea i could make these without soldering. so to achieve this it was necessary to drill the rail across the top, bearing in mind this was only going to be about 3.5mm dia this wasnt going to be easy. starting with 4.6mm stock i mounted some in my newly purchased collet chuck, these are great for holding things with a consistent diameter, so first the bar had a small centre dot drilled with a centre bit, a short stubby drill designed for the job. then it was drilled through at 1.8mm  the size of the pilot hole for an 8BA thread.

This was parted off and, then used in a vice to guide the drill, by putting the guide in the vice above the bar, the drill bit was then accurately centred over the bar, so when the 1.8mm drill bit was inserted the hole drilled was vertical and centred on the bar. 2 holes were drilled the correct distance apart.

 

[grendel]

next the holes were tapped to 8BA threads, if i had thought then i would have done the next step first. 

After tapping the holes the centres were transferred to some flat bar that would be the base, and these were drilled and then tapped.

After this step the 4.6mm brass bar needed to be reduced to 3.5mm and parted off (its a lot easier to drill the holes in the bigger bar)

It was at this point i made a mistake.

[grendel]

Next was putting some 3mm bar into the lathe, this was turned down at one end to 2.2mm for a short length, then parted off.

then the other end was cleaned up on the lathe, then i needed the collet chuck on the other end of the lathe to hold the work for the next operation.

so, the next operation was to thread the two ends of the spacer, the middle 5mm was staying the full 3mm diameter, and then the ends would thread into the top rail and baseplate.

have you spotted the error yet?

[grendel]

Yes Error, for it was only when i fitted the parts together i spotted the problem, yes to assemble it i had to rotate the parts on like threading a nut, but if i did the first i couldnt do the second, and if i trued to do it by rotating the rods, the bottom would unthread as fast as i threaded the top on, i needed a way to overcome this. thinking about it i had some 3mm brass tube that was 2mm internal diameter, i wondered if i could get the 8BA thread down the centre and use this as the spacer, but no, 8BA is 2.2mm plus i now needed longer sections of thread, so with this in mind i tried turning some 2.3mm brass bar down to 2.2mm for the thread.

This wasnt so easy as the bar flexes too much, but eventually i had a section that i was happy was the right size to thread.

As it happened i slowed the lathe down to let it do the work, and when it reached the end of the section i had thinned down, it carried right on and threaded the rest as well, great i thought, and prepped two more lengths by sanding a short taper on the end. 

 

[grendel]

With the rod threaded next i needed some spacers, so the 3mm tube was fitted in one end of the lathe and the collet chuck in the other to hold the tap. i then proceeded to tap and part off 10 spacers 5mm long threaded 8BA internally.

then i needed to clean up the other ends of the spacers and clean the threads out where i had done that.

this ended the machining work, i do have 4 more to make, so you just need a picture to show the finished item.

oops not a great picture, i will get some more, i just need to trim off the thread and smooth it up.

[grendel]

three done two to go

[BroadAmbition]

Fascinating       

Griff

[JanetAnne]

Would left hand thread one end have helped with the original version?

[grendel]

yes it would, but I dont have a left hand 8BA tap or Die

[MauriceMynah]

1 hour ago, grendel said:

yes it would, but I dont have a left hand 8BA tap or Die

And WHY NOT ???????

[grendel]

1 minute ago, MauriceMynah said:

And WHY NOT ???????

because I havent found any at the boot fairs

[grendel]

Apparently 8BA left hand taps and dies are available, its about £23 for the full set of 3 taps plus the die.

https://www.tracytools.com/taps-and-dies/left-hand-thread-taps-dies-ba?product_id=1485

Probably a bit of a specialist thing though

[grendel]

i forgot to say last night that the remaining two cleats have been completed.

so here are some pictures with parts placed roughly in their correct locations but not yet fixed in place, as i dont have complete pictures for the whole cabin tops, just segments

[ranworthbreeze]

Peter the model is looking well and is a testament to your skills and patience.

Regards

Alan

[Ray]

Beautiful! 

[grendel]

now did i make two of the forehatches when i made model #1, if not i need to print another, just trying to figure what else i need to make.

doors, i need doors, bifold for the rear doors and some for each of the cockpit steps

 

[grendel]

no need, just found a spare forehatch, i have just chromed the rims, i will need to darken the back of the translucent section.

[Lastdraft]

On 22/06/2020 at 10:15, grendel said:

Apparently 8BA left hand taps and dies are available, its about £23 for the full set of 3 taps plus the die.

https://www.tracytools.com/taps-and-dies/left-hand-thread-taps-dies-ba?product_id=1485

Probably a bit of a specialist thing though

I think you can safely consider yourself a specialist, Ive been following this for months (or is it years ) I am in awe of your skills, the model nearing completion now looks magnificent. Can I ask what you will do with the model when completed ?

[grendel]

this one is for the owners of Broad Ambition, the other model #1 will be my one.

[ZimbiIV]

Sorry to be a pest but if you look at always hobbies/cornwall model  boats you can get a working search light and nav lights.

Looks very good.

paul