Bentley 4 1/2 litre Blower in 1/12th scale - may contain Airfix.

[Brandy]

I'll definitely buy a dash set from you if you want to make them available. That was the last major item I couldn't figure out!

 

Ian

[nick]

When was version 1 of anything ever the best? It's rough, but as a proof of concept, I think it can be made to work

 

 

I just cant get this engine turning right, I'm going to have to try something new. The CNC bit is great, I even found the Gcode to re-zero the tool as it wears, its the combination of tool, material, speed, pressure and abrasive, I've tried cork, MDF, Brass, Mild steel, shaped tools, Pumice powder, coarse valve grinding paste, T-Cut and even toothpaste, but nothing is looking right. I think it's the scale. Stuff that works for full size doesn't work with a 3mm tool. I think a perfectly flat faced end mill might work, but I',m struggling to find one, they all have a slight angle to the face.

 

I will continue the research. The 3D printing, whilst scale, is just too fragile, so I need to beef some bits up to be practical.

 

I need to tackle the instrument faces next. Drawing them is no problem, I've never cracked decal printing either. I don't mind spending a few bob on a machine, but I can't actually find one. Ancient Alps things seem to be popular, but really? anyone know the correct answer? I have a decent ink jet and it doesn't work. The formulation of Epson inks slides off all makes of decal paper I've tried and you just can't resolution or sharpness IMHO.

 

Nick

 

[albergman]

Nick 

 

I have many, many Dremel size tools and I wonder if you've considered some of these?   You may have to buy a larger pack of the in many sizes to get the ones you want but they're pretty reasonably priced on Amazon.   I would try the grinding "stone" first (third image).

 

 

 

 

Frank

 

 

Edited May 22, 2023 by albergman
Wrong image selected

[Jo NZ]

4 hours ago, nick said:

 

 

 

 

 

I just cant get this engine turning right, I'm going to have to try something new. The CNC bit is great, I even found the Gcode to re-zero the tool as it wears, its the combination of tool, material, speed, pressure and abrasive, I've tried cork, MDF, Brass, Mild steel, shaped tools, Pumice powder, coarse valve grinding paste, T-Cut and even toothpaste, but nothing is looking right. I think it's the scale. Stuff that works for full size doesn't work with a 3mm tool. I think a perfectly flat faced end mill might work, but I',m struggling to find one, they all have a slight angle to the face.

 

 

 

I need to tackle the instrument faces next. Drawing them is no problem, I've never cracked decal printing either. I don't mind spending a few bob on a machine, but I can't actually find one. Ancient Alps things seem to be popular, but really? anyone know the correct answer? I have a decent ink jet and it doesn't work. The formulation of Epson inks slides off all makes of decal paper I've tried and you just can't resolution or sharpness IMHO.

 

Nick

 

Hi Nick

End mills always have some clearance angle on the bottom. Have you tried slot drills? They are flat bottomed, and available in two flute and three flute  (sometimes called a universal or slot/end mill) styles.

Are you using a sealant over your printed decals? A brush over with Microscale liquid decal film stops the ink running. Another alternative is to print onto photo paper.

[nick]

5 hours ago, Jo NZ said:

Hi Nick

End mills always have some clearance angle on the bottom. Have you tried slot drills? They are flat bottomed, and available in two flute and three flute  (sometimes called a universal or slot/end mill) styles.

Are you using a sealant over your printed decals? A brush over with Microscale liquid decal film stops the ink running. Another alternative is to print onto photo paper.

Just ordered a set of slot drills, I think that’s the answer - thank you. 
 

yes I use clear.
 

With epson papers, you can get deep rich colours that are pin sharp as a lot of ink is applied and the paper formulation takes it without bleeding. 

 

What I mean is, when you buy cheap, non-epson photo paper, epson inks don’t adhere properly, so the ink sits on the surface and either smudges, doesn’t dry or just slides off. In any case it’s not possible to get sharp, solid colours at detail.

Every decal paper, and I’ve tried at least 10 different ones behaves in the same way as cheap photo paper in my experience and epson don’t appear to make decal paper. 
 

maybe I just need to buy another make of printer with a different ink formulation, which I must admit, will annoy me as I have a high end A3 photo printer that is otherwise very capable. I know my machine is fussy about paper. 
 

what I don’t want to do is buy a non-epson inkjet only to discover it has the same issue.
I’m toying with a colour laser, but it’s hard to get a straight answer out of anybody about capabilities for decal printing. I wouldn’t entertain one for photo printing and they all look a bit rubbish and seem aimed at ‘good enough’ high volume colour for office printing, ie pretty graphs not proper photo printing. 
 

I know large format pro Roland printers will produce decals, but I don’t think they are especially high resolution when I ask my professional printer friends about them, plus they are huge and costly. 
 

I don’t mind spending some money on this, I just can’t find a machine that does this properly. Everything pro is aimed at large format and tee-shirts and mugs which isn’t what I need. 
 

Maybe I need to blag a Cartograf factory tour! although I have always found them to be frosty and unhelpful when I have contacted them about small production runs. 

I would love to solve this as it’s ‘the missing piece’ of stuff I can do myself now! In for a penny etc.

 

thanks for all the support and encouragement 

 

Nick

 

[nick]

6 hours ago, albergman said:

Nick 

 

I have many, many Dremel size tools and I wonder if you've considered some of these?   You may have to buy a larger pack of the in many sizes to get the ones you want but they're pretty reasonably priced on Amazon.   I would try the grinding "stone" first (third image).

 

 

 

 

Frank

 

 

Hi Frank hope you’re well? Yes that’s where I came in, I tried all that stuff in the first place, although in fairness in a Dremel which isn’t stiff enough.

 

I might go around again with my CNC machine which is a lot stiffer and see what happens. I’ve got high hopes for Jo Nz’s slot cutters right now!

 

Nick

[PROPELLER]

Hi Nick!

Take look at:

 

https://watches.alco.ch/en/109-spotting-sticks

 

Dan.

[nick]

9 hours ago, PROPELLER said:

Hi Nick!

Take look at:

 

https://watches.alco.ch/en/109-spotting-sticks

 

Dan.

That’s interesting. I need 1/8th shank and they appear to only be available in 3mm, I’ll see how I get on with the slot cutters but they may be an option too. It’s knowing what this stuff is called it’s obviously out there it’s just finding it!

 

thanks again. 
 

Nick

[maybach_man]

Try here https://www.hswalsh.com/

[nick]

I think I may have solved my decal problem. I’ve also upwardly revised my previously low opinion of colour laser printers having just bought one. This is paper but I’ve got some laser decal paper coming tomorrow 

 

 

much better than anything my inkjet ever spat out. 
 

Nick

[nick]

Quick cellphone photo with bad lighting, but I reckon my new color laser isnt too shabby. This is on laser decal paper now and is infinitely better than the inkjet stuff, in fact you don't even laquer it, print it, wait a bit and you're done. Clearly witchcraft.

 

Still finding my way around, but it seems the best thing to do is export the vector from illustrator as a bitmap at say 1200 dpi actual size into photoshop, then print from photoshop. Why? well although it sounds counter intuitive AI isn't that great at converting the very small scale vector into a raster (its always ultimately going to be a raster to print, ie not plot) and by handling the bitmap to print yourself in photoshop you can get more control over it.

The printer settings aren't really designed for tinkerers either but I'm getting there. Still got thae age old problem of white/clear paper, but I'm going to try and laser cut these next with the CNC machine which might help - watch this space.

 

I might actually have a go at building a model at some point in the future too, you never know

 

Nick

[nick]

On 5/23/2023 at 12:37 AM, Jo NZ said:

Hi Nick

End mills always have some clearance angle on the bottom. Have you tried slot drills? They are flat bottomed, and available in two flute and three flute  (sometimes called a universal or slot/end mill) styles.

Are you using a sealant over your printed decals? A brush over with Microscale liquid decal film stops the ink running. Another alternative is to print onto photo paper.

well the slot drills were a fail, they still seem to have clearance on the bottom face, maybe I just got the wrong ones? I'm playing with test pieces now at different drill depths (so pressure) and durations with soft faced tools and abrasives, lets see what that does.

 

I think tools dont have a flat face for a reason - chatter, so maybe cracking polishing/abrasives is the correct answer after all.

 

I'm also looking at a material called Cratex which seems to be ideal for the task, just hard to find and expensive - like 30 quid a stick. Im also going to have to machine it down and mount it on a 1/8th spindle somehow.

 

I'm in too deep to not solve this now, so stay tuned!

 

Nick

[nick]

and heres a render with the virtual decals applied. Just needles to draw next!

 

 

Nick

[nick]

Needles AND GLASS now. I spoil you guys, I really do.

 

 

Nick

[nick]

I feel a bit like Thomas Edison did when he said he failed to invent the lightbulb about 10,000 times. to recap, I've tried varios different drill depths (so pressure on the tool), spindle speeds, dwell (time the tool is in contact with face) tool faces - mdf, cork, oak and different abrasives - pumice powder, T-cut, Valve grinding paste, talc and toothpaste, all with varying results. 

 

This gives me about a million combinations or so it seems, so I generated a test piece to try a range of pressures, speeds and dwells for each tool/ cutting agent combination, and after what feels like about a year of experimenting with every possible permutation, I **THINK** I've finally found something that works! what a PITA.

 

Fotos soon (if it works!)

 

Nick

[nick]

This is the best version so far I think and isn't far off IMHO.

 

 

 

 

[nick]

getting the decals ‘dialled in’ next. Sorry about that.

I think these are better. They're right at the limit of what the printer is capable of here

 

[nick]

Still plugging away at this. A coat of gloss actually improves the decals contrast for some reason, so that’s a win.
 

As I thought the gauge needles are too small to 3D print so I’m going to have a go at laser cutting them from heavyish paper next. I suspect I’ve got a focusing issue with my laser as it’s currently bouncing off paper and I’m assured it should cut it, so I’m just waiting on a support call for that. 

 

I’m also going to try and cut the ‘glass’ for the gauges from thin acetate on the CNC router. I’ve successfully formed the supercharger oil dropper sight glasses with a simple tool and drilled plate and thin clear sheet warmed up with the heat gun. Fotos to follow. It’s finally starting to look OK!

[Noel Smith]

Hi Nick

Very interesting developments on the Bentley dashboard.

I noted that you have slot drills on order to do the engine turned finish.

Another alternative worth looking at are tungsten carbide bits for circuit boards. I believe that you can get ones with a flat instead of pointed end that look similar to slot drills. Extremely brittle due to their hardness, but you would only be using very light vertical pressure anyway that they were designed for.

I like your laser printer instruments. The late Gerald Wingrove used to draw instruments individually to size on black or white card, worked out what distance to set the camera at, then photograph a group of them together . He then used the resulting black and white prints done on glossy paper for his gauges.

[nick]

51 minutes ago, Noel Smith said:

I noted that you have slot drills on order to do the engine turned finish.

Another alternative worth looking at are tungsten carbide bits for circuit boards. I believe that you can get ones with a flat instead of pointed end that look similar to slot drills. Extremely brittle due to their hardness, but you would only be using very light vertical pressure anyway that they were designed for.

Hi Noel, I have the slot drills now and found that they too don’t have a 90° degree cutting edge either. As it happens I already have a spot cutter PCB bit as my CNC machine is capable of fully producing double sided PCBs as it’s accurate enough to cut the tracks. 

Unfortunately though, the ones I have all have a centre, almost like a Forstner bit, as they are designed to pick up on an existing hole in the circuit board.

 

As for the dashboard, so far the most successful versions are using polishing with compounds rather than cutting, I’ve overcome the rapid wear issue as I found the Gcode to re-zero the cutting head, so after every 20 or so operations it goes off to ‘peck’ the Z height sensor pad and thus allows for the wear. 
 

I do have a cratex rod arriving soon too, maybe tomorrow, which I have high hopes for! Watch this space. A 6”x 1/2” rod of the stuff is £30! it’s about the same price as gold, so it better be good. 
 

Nick

[Jo NZ]

Try a jewellers supplier. You can get rubber abrasive rods in 2 or 3mm diameter and about 20mm long for a couple of quid. Might be easier than cutting down a 1/2" rod.

[nick]

I can also report that laser printer decal paper is marvellous, it takes the toner beautifully, it’s as thin, if not thinner than commercial decals and conforms well. I have gloss lacquered mine as they are fragile otherwise, but will work without this.
 

I’m looking to hit it with my CNC laser next to avoid the tedious cutting out required. In this case the black burnt edge of the laser cut is exactly what I need as I’m having to use white substrate decals and the edges need the sharpie pen treatment when cut manually as I’m doing now. 
 

I was extremely reluctant to buy a colour laser printer, but it’s absolutely ideal for this task. They’re still not much good at ‘proper photos’ but for graphical (ie solid, even blocks of colour with sharp edges like this) they’re excellent. 
 

of course, since buying it and searching for years for a proper solution, I stumbled upon this, which looks great. 
 

https://www.ghost-white-toner.com

 

basically it’s white toner. So you plug in a white toner cartridge instead of the black one. Your design has to have the white backing bit drawn as black for this part, Print your white substrate on clear decal paper, change the white cartridge back to black, then pass the paper through a second time to overprint the actual design.

 

of course if you just want white lettering on a clear background say, just do the first bit. 

 

[Chaoarral]

22 minutes ago, nick said:

I was extremely reluctant to buy a colour laser printer, but it’s absolutely ideal for this task. They’re still not much good at ‘proper photos’ but for graphical (ie solid, even blocks of colour with sharp edges like this) they’re excellent. 

 

Which laser printer and decal paper did you buy?

[nick]

2 hours ago, Chaoarral said:

Which laser printer and decal paper did you buy?

HP Color LaserJet Pro M255dw and Hayes Paper Co. Waterslide Decal Paper Laser White - Premium A4 Water Decal Paper Laser Printer - White Transfer Paper, 20 Sheets https://amzn.eu/d/gc6Tqj2

 

there are 1200 dpi colour lasers (such as canon) that are worth looking at too 

[Noel Smith]

Hi Nick

Like another poster suggested with a link.

H S Walsh look like they just might have something. I have just been looking at their Hatton Garden shop website. They also have a branch in Birmingham in their jewellery quarter I believe.

 

Just a thought. The slot drills and tungsten carbide bits that you already have. If you are looking to obtain a true flat end on them it might be worth contacting a local engineering tool maker who will probably have a surface grinder with a fine grit wheel. They could mount the bits in a chuck holding the bits vertically under the wheel. A few quick passes should level off the bit ends for you, and might just give you the absolutely flat ended tools that you are looking for. If you show them an example of what you are trying to achieve, in my experience engineers are generally fascinated by what model makers are trying to do and generally willing to help in any way. If you could utilise those tools you already have,  it might save having to worry about wear compensation when abrasive tools are used.