Member postings for Andy Bladen 1

Thanks for all your advice most helpful

Does anybody have a good tutorial on lost wax casting it's something I've never done before

Your joking I could not build a V12 ! Would be nice I've seen people build them but my engineering skills are not that good!

So alu tubes could they be soldered or brazed rather than glued it needs to be capable of bearing some weight

That would certainly be easier but as its a a flying model I need it to be as light as possible so aluminium would be ideal

Hi all

I'm building a 1/4 scale rc spitfire I need some advice on maching the undercarriage

Would it be possible to mount a solid piece of alu into a 4 jaw chuck carve out the outer detail and bore the inside to correct diameter to allow an oleo tube to fit inside and machine the rest with a milling machine I know it's a big job can you also suggest a suitable lathe which for the job ?

Thanks

Andrew

thanks for that diagram I see what you mean now

i have done a little work today but not completed the component yet as I need a new endmill to recess the front part

i managed to use the broken one for milling it out

john

they. Look a bit heavy to be honest I may have to make something from alu shouldn't be that difficult if I take my time

I will get hold of a t cut slotter and hopefully if it's machined accurately enough it should just slide on the rail

we will see !

Neil

the mechanism will be hidden away so that might work as long as it travels up and down the slope without binding

Andy

John

Around 20mm square would be ideal they have to be quite small and a total of 8 I'd need there are 2 for each flap per wing

I've looked on Google but they seem to be really expensive and a bit to big

failing that I will have to attempt making the top one 2mm roller bearings of some kind would work

cheers Andy

This is the next part I need to create or something similar

Andrew

thanks for that info I will try that method this weekend as soon as I buy a new endmill!

Still a little unsure about the tapers and how that works

if you could post a diagram of some kind that would be great

the crucial part where the accuracy needs to be precise is the slope

this is where I have to make a carriage to slide up and down

i was hoping to use a t slot cutter if I can find one small enough (around 6.5mm)

Murray

great idea I never thought about using spacers this should allow the chippings to fall through and hopefully prevent clogging

I tried using wd40 but it just made a paste and the alu welded itself to the mill

this uses should hopefully work th least amount of times I have to un clamp the material the better

as you say most of the time is taken up setting the work piece

Daft question. But how would you clamp the work piece to the table ?

my first attempt was to bolt the alu down onto a piece of wood so not to mill into the table problems I found was there wasn't anywhere for the chips to fall away apart from blowing them which did work to a point

I thought about using a vice but once I cut most of the frame I thought the vice might crush the remaining metal

Ian

Great advice I was blowing the chips away it makes a lot of mess but worth it to help keep the cutter free

surprising how much mess can be made from such a small part !

Once again thank to everyone who has taken there time to contributed to this thread it's certainly invaluable advice I will take on board to try and improve my work

i am a complete newbie and still learning we never did a lot of engineering and metal work at school sadly

Some interesting advice thank you all

i will try a 2 flute hss endmill and see if that works better

as mentioned above I did have problems with the chips welding to the mill maybe I was going too fast and clearing them away enough especially using a 4 flute mill

Thanks for the advice everyone still much learning to do

Andrew would what thickness end ill should I use for the part it's around 4inch long and 1/4 inch thick extruded alu

Well tonight's progress has been halted

End mill has broken

it looks to be a 4 flute hss type so I'm going to try a 3 flute it was clogging up quite a bit

Here are some pictures of the machine I'm using

the alu is 1/4inch thick not sure if it's alloy ? It didn't say in the listing I bought from ebay it is extruded alu

Mike I'm not sure what you mean by rake head?

I created this structure from the above drawing at roughly the size it needs to be to fit into the rear of the wing trailing edge

as in the full size there isn't a lot of room under there especially with spoilers and servos underneath

this prototype was just to get a feel for the machine as I've never used one before

the problem with it apart from a few rough edges is the top part of the angled edge

a carriage has to slide up and down and this bit needs to be very accurate I really need a thinner end mill

what I should have done was mill out all the gaps parallel in one go instead of re setting the work piece

the angled slope was actually cut with a jigsaw and sanded smooth with a belt sander

that was my 2nd mistake because it's not straight enough really

the sliding carriage is going to be the most difficult piece to make

it will probably take another 12 months to finish the plane completely as I keep adding more scale detail I must also consider the weight as it's intending to be a flying model (I hope)

Thank you all

i will slow the speed Down a bit and take my time for the next pieces and try fluid as I did not use any previously and there was times when the alu clogged a bit again I'm learning as I go

I've read that techniques such as climb milling are useful so feeding the work against the cutter

on this piece I made I just went back and forth most of my time was taken up setting the work piece I guess this is where accuracy comes to play

I'm certainly enjoying it so far especially if the mechanism does actually work

Hello all

thought I would share my first experience using my newly bought milling machine

although the quality of the part I've made isn't great I'm sure with some more practice it should improve

anybody have any tips on getting a smooth finish and recommended cutting speeds?

Im working with aluminium