Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Other Technical Questions... => Topic started by: dougal99 on August 24, 2007, 07:51:48 pm
-
Hi all,
I am currently building Model Slipway's kit Sentinel which requires some small slots 3mm long and approx 0.5mm wide to be cut into 1mm plastic. I have been trying it out on scrap but cannot achieve the required width. I always end up with a slot that's too wide.
I have been drilling 3 x 0.5mm holes and trying to join them with a sharp pointed blade. Has anyone got ideas on how I might achieve the requirement?
Ta
Doug
-
I have not tried such a small slot myself, but would suggest a pointed surgical scalpel.
You could score the outside edge carefully and also score across the inside from corner to corner, creating a cross. Then push the centre of the cross to break the scored lines outwards. Should then not need trimming, as the 1mm breaks cleanly.
Best of luck and mind you fingers.
Ken
-
Hi there dougal 99
Have a try at this method:
clamp two steel straight edges in the vicinity of where you want the slot - by using either G clamps, clothese pegs, or whatever - clamp the two straight edges 3mm apart and this will give you a good edge to cut along with the scalpel blade, after first drilling 2 x 3mm holes either end of the length of the slot. Ive included a 'scraggy' sketch :D to try and explain it.
aye
john e
bluebrd
-
Use 1/64th ply! I'm building a Dean's steam yacht Medea at the moment which requires a lot of cutting out of plasticard. Give me plywood every time!
-
Guys,Guys
Thanks for the input. However, the slot is 3mm by 0.5mm thats .15 square cms. No room for cross cuts or clamps as the superstructure is already built thus no plywood.
Any other ideas?
Doug
-
I would have a play with a .5mm drill bit or an end mill if you can get one and run it along a straight edge.
Set the depth somehow with a collar or something and see what happens.
-
I think the only way to do it would be to lay a straight edge of some sort along the length of the slot and run a 0.5mm drill in a power drill along it for 3mm. Then use a very sharp pointed scalpel to clean it up. It's such a small hole that you will have trouble in plastic whatever method you use. It's too small to make up a punch.
Snap Bunkerbarge!
-
Guys,Guys
Thanks for the input. However, the slot is 3mm by 0.5mm thats .15 square cms. No room for cross cuts or clamps as the superstructure is already built thus no plywood.
Any other ideas?
Doug
It's actually 1.5 square mm
-
I think the only way to do it would be to lay a straight edge of some sort along the length of the slot and run a 0.5mm drill in a power drill along it for 3mm. Then use a very sharp pointed scalpel to clean it up. It's such a small hole that you will have trouble in plastic whatever method you use. It's too small to make up a punch.
Snap Bunkerbarge!
Great minds etc...etc...
-
Thanks for the input I'll see what I can rig up with a drill as I don't have access to a milling machine.
Doug
-
If you are drilling in plasticard especially with very thin drills have a small squeezy bottle of water handy and drip it as to the drill it stops the drill picking up plastic when it gets hot and sticks to the drill ,so you get a clean hole as the drill does not grow in dia with plastic, it only needs odd drips .
Peter
-
I have an X-acto hand saw with a 0.35 mm blade. This produces a slot which is about 0.5 mm wide.
-
Yes, but I bet the blade is more than 3mm long. OK if it's an open ended slot but I got the impression that it's a closed one - or am I wrong? If it is open then the Xacto knife saw blade would certainly do the job as you say.
-
I am intrigued as to where on the Sentinel these small slots are. I built one a couple of years ago, and don't recall being faced with this problem. Mind you, my memory isn't so good now either.............what were we talking about??? ??? ;)
Peter.
-
Is this piece of plasticard allready fixed on the boat ?
Can you take a picture for us. It's intriguing. If you went wrong, then is there a damaged piece still on the boat ?
Sort of problem to get the old grey cells moving. ( as Pieorot would say).. O0
Cheers...Ken
-
Could you laminate a piece of brass shim on top with the slots in it.
Peter
-
If you have more than one slot it sounds like you need to make a jig.
A possbile solution.
A piece of brass sheet (or other metal) and carfully drill the the two 0.5mm holes at 2.5mm centre to centre. drill other holes in between and then use a 0.5mm router of the drill bit as a router.
On second thoughts if you have a pillar drill and one of those sliding vices you could use a piece of mild steel. As it is thicker and harde than brass you will get a better vertical.
The jig can then be clamped onto the plastic sheet.
But I am sure somebody can come ouy with something smarter than this.
But at 0.5mm I would not want to paint it.
-
How do you paint a 0.5mm hole ? ???
-
Don't know if this helps Doug but I bought a couple of those cheap little wooden handled chisels, you know, the type you find in every pound shop.
I then ground the blades down to whatever size and shape that I neededthe blades are as close to 1/2 mm as dammit in thickness and you can grind them down in width no trouble......
-
Thought you'd have known that Dicky
Carefully mask round the hole - spray - remove masking - voila! A painted hole! :D :D :D :D :D ;D
Danny
-
The slots/holes are required to accept brass 'u' pieces which are the supports for the vertical handrails either side of the ladders. There are four supports on each side of the superstructure each requiring two slots. The superstructure is already built as I hadn't considered the railings etc until now. Moral RTFM.
Peter, bummer I was hoping you'd come along with ready solution.
Tiger Tiger, your solution was how I was going to try it unless somebody gave me a better idea.
I can't get into the workshop for the next few days, painting the floor, so the job will remain on hold till then. I'll let you know all how I get on.
Bigh, your idea is also an approach I thought about but I have no grinding wheel (yet!).
Thanks everybody for the help.
Doug
PS Omra85, I tried your method of painting holes but they all come out as the same colourless space. O0
-
PS Omra85, I tried your method of painting holes but they all come out as the same colourless space. O0
I told him it wouldn't work Doug, but you know what these youngsters are like. ::)
-
My uncle used to make holes for a living, he swears that he made the first 1,000 holes to fit in Polos, I know he used to bring sacks full of holes home for us idiots to play with. I woildn't lie to you fellas, honest.... ;D ;D ;D
-
Yes, but was he any good with slots, I believe different qualifications were needed?
-
I do not know if he did slots Colin, he fell into one of his own holes one day and came out in Oz. It took him 2 wks to get back and his boss sacked him for leaving his hole without permission, he went off and joined the legion and the last we heard was that he was making upside down umbrellas. Harry
-
I would be temped to make a hole larger, use styrene filler, and plant the fitting in the filler before it set, then hide it under the paint. Sometimes I really am glad that I'm not a craftsman...
There used to be a slotting tool that looked like an engraving tool fitted with what looked like a short piece of junior hacksaw blade with the teeth at the end. Downside is the end was probably bigger than the holes needed. Drilling looks the best option, but I would do my initial holes with an Archimedes pin drill, and use the inevitable broken bits to form the slot in an electric drill run at low speed with water for cooling.
-
Here's a wee snipet. I have used piano wire in a mini power drill for this, as long as you have the piano wire dead straight, put a small length in the drill chuck and just give it a quick waz, without applying too much pressure otherwise the piano wire will bend and the drill will go daft. Give it a try on some scrap and see how ya go.
Paul...
-
How do you paint a 0.5mm hole ? ???
.
Like that O0
-
Still no picture of this hole ... ::)
I had a look at my new metric ruler to see what 1/2 a mill looks like. It's rather small innit.
How about heating up a piece of copper at that size and plunging it into the plastic ?? (In a precise sort of way)
I fit my stanchions by heating them with an Iron.
Cheers...Ken
-
Kenny,
Paint still drying on workshop floor, then I have to move everything back. :(
I thought about a heated wire but I don;t think it would be accurate enough. I have sent for some watchmakers broaches, a set of 12 0.3mm to 0.65. Expo tools. Hopefully these will do the job.
I will post a photo when the job is done, as it is there is no hole to show.
Doug
-
I will post a photo when the job is done, as it is there is no hole to show.
Doug
But aren't holes invisible ? Isn't this why you can't paint them ? ??? :-\
-
Dicky,
This is getting complicated I'll have to look into it ;D ;D O0
-
Kenny,
Paint still drying on workshop floor, then I have to move everything back. :(
I thought about a heated wire but I don;t think it would be accurate enough. I have sent for some watchmakers broaches, a set of 12 0.3mm to 0.65. Expo tools. Hopefully these will do the job.
Does it need to be precise?
It is to locate a component that will be glued in (I presume) to it will be hidden.
And the adhesive will cover a multitude of sins.
As will the final paint job.
-
I cut these tonight , Mark hole, use a 0.04 drill protruding out about 3mm ish, hold or tape a straight edge on few drops of water(important)
move the drill from left to right to help stop climb . Di Daaaaaaa the one on right was the first try not very good
Peter
-
As tigertiger implies, the model is only there to keep the paint the right shape. If it is going to be painted, you will only see the paint, what goes on beneath is your secret.
-
HS93/Peter
Thanks for the demo I'll give it a try, when I return from the family wedding this W/E (if not one thing then another).
TT ans Malcolm,
I try to work as accurately as I can (which often is not that accurate) so that I end up with the best I can do. I know that most other people will not spot small imperfections, but to me they look like enormous carbuncles. Each to his own. 8)
Cheers
Doug
-
Try on scrap first it took a couple of goes, then it was easy.
Peter
-
OK - just came upon this thread and thought it was time to let this suffering stop!
Ref Sentinel - I designed the bl00dy thing and there's no way that you can cut slots that small - neither do you need to. The brass U-pieces are soldered or superglued upside down onto the stanchions and act as stops when you push the stanchions into their holes in the deck. On the full-size Nellie these U-Pieces are actually mounting brackets which are welded to the deck and the stanchions fit into sockets bolted to the topside of them, so the stanchions don't go into the deck at all. Yep - you can see daylight underneath them.
Crazy way of doing things, but that's Vospers for you.
Doug - if you look at the photos I sent you there's one of the aft deck rails which shows the towing clench and the bases of several stanchions. You can clearly see what I'm going on about from that, mate.
Sorry for the confusion. Off to find a hair-shirt..........
FLJ ::)
-
Dammit no holes to paint then, Danny will be disappointed. :(
-
You can laugh - but when I've perfected my skill .......
There's money to be had in hole painting :D :D :D :D
http://www.artgallery.com.ua/bigpicture.php?Artist=46&ID=002&lng=it (http://www.artgallery.com.ua/bigpicture.php?Artist=46&ID=002&lng=it)
Danny
:P
-
:D You kept us waiting for that one Dave
-
Sorry, Harry. Like I said, I just tripped over the thread (p155ed again). Itching like hell from this hair shirt, now.
I'm sure Doug is doing a blinding job of his model of Nellie - it's taking him long enough!!
FLJ
BTW It's nice to be away from the Ward Room and back among the living
-
Hello folks...In response to DickyD question how to paint a 0.5mm hole..
All you do is get a 0.5mm drill turn it upside down so the blunt end is to be touching the plastic card ..dip this end in the paint you require so as to just cover the end of the drill and then you touch this onto the plastic card and hey presto one 0.5mm hole painted !! simple.
It may take a couple of practice tries to get the right amount of paint on but its easy when you have had a couple of practice goes, I have used this technique when painting very small portholes on a superstructure and it looks very realistic.
Hope this helps Sub. ;) ;)
-
Hi All
Just to clear a few things up. I have had a very friendly exchange of emails with FLJ and we agree that the slots are needed. O0 He recommends using heat as suggested by Kenny. I will experiment but am still dubious about accuracy (mine). I will also persevere with the drill etc and let you know what I finally use.
Yes the model is taking a long time, I have built 3 others since I started it, but I want to make it as good as I can. FLJ has been very helpful and I am grateful to him, even if he did have me doubting my sanity when he said the slots weren't needed. :D :o
Any way feel I'm on the home straight now.
Cheers
Doug