Xairflyer's first MDF CNC router

[Mr.Chips]

Thanks Xairflyer, for the tip on "Machine Taps".

Would a machine tap also reduce the possibility of tap breakage when tapping alum? I'v broken a few taping alum, seems the chips stick together and jam, even when backing up ever so often.

Hager

[buscht]

Mr. CHips, You might want to use Tap Magic cutting fluid for Aluminum. It will solve your chip sticking and jamming.

[buscht]

xairflyer, When screwing MDF together I think the best fastener is a confirmat screw. Here is a link that shows how one guy uses then in cabinet work.
http://www.norrod.com/shop/screws/
You don't need that fancy drill bit, but you need a clearance hole (8mm) for the the shoulder and a pilot hole (5mm) for the threads.
This eliminates the tiring tappping of MDF and holds fantastic.

[xairflyer]

Yes I have used these before they are common to flat packed furniture you buy at DIY stores.

Tapping should not be tiring if you use a cordless drill !!

[davesaudio]

The K179 unipolar driver board kit was only £9.95 works great had my motors on the bench last night buzzing away.

good deal those, wish I had seen those before I started my homebrew version. its pretty much just the cost of the parts...

[avsfan733]

Originally posted by buscht
Mr. CHips, You might want to use Tap Magic cutting fluid for Aluminum. It will solve your chip sticking and jamming.

Tap magic is incredible stuff. Personally i usually back the tap all the way out of the whole and blow it out every quarter inch or so with aluminum

I spent the last week cutting and tappin 4140 and was amazed at how well it actually tapped, so much easier than i expected

[xairflyer]

Mr Chips,

Machine taps work great in all materials, and by their design, are not meant to clog up. But a tapping fluid like buscht mentioned is always recomended as well.



Davesaudio,

You should also look at the K109 kit it uses the UCN5804 chip and has half step as well. £14.95stg.
It is Limited to a 1.25A motor in it's out of the box setup.

I have ordered one to play with, as I want to build a pan mount for my CCTV camera.

[xairflyer]

Started making up my 4 jaw chucks today for the rails.

Only material I could get (without having to wait a week) was 1" nylon. Sorry I never waited !!!

I decided to drill out the clearance holes for the 1" tube and used a 1 3/8" hole saw.
Nylon is a pain to cut at anything faster than you can do by hand.
It heats up so fast, I was cutting at the slowest speed on my drill press, and it still kept heating up, clogging the cutter, even the coolant was bubbling with only small cuts.

Eventually got four holes cut for the x axis blocks and then I tried to cut them into 3" squares (as I left them in one piece for easier drilling) I decided to use my jigsaw as I had broke the blade in my bandsaw last week.
Tried all different pitch sizes of blades and all it did was melt !

Ended up Cutting it with the hacksaw which cut it fairly well and easier than I thought.

Note: Best thing to cut nylon is a hacksaw, bandsaw would be ok to if you have access to one.

After all that work I Still have to clean them up, and probably still won't get that good of thread when I tap them.

Would not recomend the use of standard nylon, especially that thick, Delrin is a far better material.

I could have made them up in 1/2" alloy plate in half the time, but I did'nt really want to mix alum with the wood if possible.

I am going to make some out of 1" MDF for the y axis just to put to the test. I think with the great thread my machine tap makes, along with the thin super glue I will have just a good of job as the nylon ones.

Time will Tell !!!!

[balsaman]

The CYa will help a lot with the threads. It's a trick only a model airplane guy knows!

Eric

[xairflyer]

I think being a model and full size flyer is what gave me the motivation to build one of these machines.

I can see lovely ribs etc being spat out, as fast as I can stick them together.

I want to build a 1/4 scale R/C model of the aeroplane that I Distribute and fly.
The wings are tapered and swept back so it means a lot of cutting by hand.
This will be my first project when the machine is up and running.

I have a lot of little things I want to make for the full size version's that I have to make by hand now.

[creative_mind]

xaeroflyer,

You have a beautiful flyer in the picture. Do you have the plans for it? I'm interested in building one myself.

[xairflyer]

It is only available in kit form, we both sell kits to customers and build for them.

Construction is all aluminum tubing and the covering is Dacron (polyester).

[xairflyer]

Got my steel framework made up to sit the machine on.

Made the whole thing out of 2" x 1" box section, need to paint it now with hamerite.

Not been too happy with the nylon blocks for the four jaw chucks, firstly because of the work it took to make them, and second because I am not that keen on the finish or thread quality.

Decided to make some up out of 1" mdf to try out and I am really pleased with the result.
I cut the clearance hole in the middle, with a 1 1/4" flat (spad as we call it) wood bit, and the finish of the holes is lovely.

Made big discovery on the tapping front.
I had this flash of an idea lying in bed, and decided to try tapping the holes with a Roll tap.

The difference is (hard to explain) the tap dos'nt actually cut a thread, it makes the thread by squeezing the material into a thread as it goes, so instead of material being removed (swarf) it push's it into the last thread.
These taps are normally used for tapping holes in extrusions punch out of a piece of material in order to give it sufficent thickness to actually have a thread. (a 1/8" thick piece of material would not have many threads, but this can be doubled or trippled by extruding it.

You could'nt use one in normal circumstances for tapping steel as it would jam or break, but wood and especially MDF is perfect for it.

I put it to the test and the threads are actually HARD, this is due to the squeezing of the wood to form the thread.
With the thin cyno, and then re tapped again after about 2hrs (won't get bits of glue stuck on your tap, if you leave it a while to harden) The thread quality is that good, my mate thought I had fitted inserts into the mdf.

The moral is for tapping MDF you want to get your hands on a Roll tap.

So I am scrapping the Nylon 4 jaw chucks and making them all
(x and y) out of MDF, as you can see from picture I have drilled all the holes in a 9"x6" piece ready to be cut up into 3"x3" squares.

The nylon block dos'nt even look as good !

[Mr.Chips]

"Roll Tap" never heard of that one. But the principal sounds very sound with MDF. Is this tap available in the US?
I made my first srt of blocks out of a thick cutting board and it was a mess cutting them the material wanted to melt and difficult to clean up. Finally decided not to use them and gang drilled the end plates. Put the base together today will find out tomorrow when I mount the movable table how far it's out. Hope they are parallel and level, time will tell.

Hager

[xairflyer]

I agree nylon/chopping board material, is a pain to work with, I milled up the sides of the blocks I cut, but not eveybody has a mill in the garage, so that is why I favoured MDF, as a test.

The name "Roll tap" could be an engineers term for a "fluteless tap" try that name and see how you get on.

They are in my RS catalogue, not that cheap as they are a specialist tap, but for tapping MDF brilliant.

In the RS catalogue they state "they produce threads not by cutting, but cold forming material displacement"

[TopSpin80]

I'm using Forstner bits for all my holes... MDF and cutting board material. They leave a flat bottom hole too incase you don't want to go all the way through. The hole is a lot cleanter then the hole saw holes. I drilled these bearing blocks with them, and the holes they leave in MDF are incredible.

Ernie

[Hobbiest]

Forstner bits have the bonus of making round holes as well, instead of the slightly oblong holes from a twist bit. Bearing blocks look great. What are the step sizes? 7/8" and 3/4?

[TopSpin80]

yea they are 7/8 and 3/4 the bearing isn't really tight in there, but there isn't much slop either.

Ernie

[Hobbiest]

should be tight enough once you get your washer on there. Another idea...use a fender washer that is just small enough to grip the outer race of the bearing, and drill two holes in the edge to mount it.

[ger21]

CMT makes 22mm forstner bits, for about $15. That is what those bearings are, right?

Gerry