[4]

Help milling Aluminium on a Clarke CL500M

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

Superslim

Newbie
Registered
Joined
Nov 5, 2018
Messages
6
Likes
2
#1
Hi, First post but likely not my last

I am 47 and started my working life in engineering working on capstones and lathes and then went on to sheet metal fabrication and welding till I was about 22 then ended up in sales which is what I do now.

I have always enjoyed making things and have just got into making nixie clocks and have always wanted to make one similar to Nixie Machine II Exclusive edition M.A.D.Gallery if you have a look,
So I have now bit the bullet and bought myself a little Clark CL500M and am about to start working on my clock legs, they are being made out of 12 mm aluminium plate that I've had cut to the blank sizes I need.

My legs will look a little like spider legs and will have curves and straights to machine out.

I have various end mills of all HSS sizes 2 mm - 12 mm some 4 flute some 2 & 3 flute that I will mostly use to mill out these parts, I have bought a 6" rotary table for my curves but it has been a very long time since I used any kind of milling machine so could do with some advice.
As I understand it with aluminium I don't necessarily need coolant but I have got a compressor to constantly blow away chips.
I have it on its fastest 1630 rpm
I know this is not a professional machine by any capacity it is just a hobby machine but hey this is my hobby.
Can anyone advise what is reasonably the most I can remove on each pass, so how deep into the 12 mm plate and how far in - so can I do 5 mm deep and 5 mm into the plate or less or more, what would be a safe speed to operate my power feed - should I even use the power feed

I will be grateful for any advice that will save me burning and breaking cutters until Iv'e learned the hard way

Thanks
 

Shootymacshootface

Active Member
Registered
Joined
Mar 17, 2018
Messages
109
Likes
66
#2
I've only been at this stuff for a year but I am lucky enough to have a 23 year old son that is an excellent machinist. He has taught me so much about this stuff.

For starters use WD40 while machining aluminum. I don't think that there is anything better that a consumer can easily get.
I'm not a stickler for speeds and feeds. I tend to do things a little slower. I don't do this to make money, although I do enjoy saving money by making instead of buying anything that I can make myself. I adjust my speeds by what the chips look like and the sound of the cutter. With a sharp endmill (but not the smaller ones) you can easily remove 40 or 50 thousandths at a time if your machine has enough power. I would start with 20 thou and go from there.
For rpms with aluminum I would turn a 1/8" endmill at 1200 rpms, 1/4" at 1000, 3/8" at 800, 1/2" at 5 or 600, and bigger cutters even slower. For cutting steel run things 1/3 slower the chips should be silver to light brown in color. Dark blue or black will ruin your endmill. If you see sparks or a loud squeek slow things down and use more cutting oil.
Like I said start slow listen to what your machine is saying, you can always speed things up as you become more familiar with things.
I hope this helps, good luck!
 

mikey

Active User
H-M Supporter - Gold Member ($25)
Joined
Dec 20, 2012
Messages
4,363
Likes
4,715
#3
... I have it on its fastest 1630 rpm
I know this is not a professional machine by any capacity it is just a hobby machine but hey this is my hobby.
Can anyone advise what is reasonably the most I can remove on each pass, so how deep into the 12 mm plate and how far in - so can I do 5 mm deep and 5 mm into the plate or less or more, what would be a safe speed to operate my power feed - should I even use the power feed.
Welcome to HM, Superslim!

I am attaching some info for milling aluminum from Niagara Cutter below. Here, you can see that the max axial depth of cut should be no more than 1.5 times the diameter of the cutter. So, you can engage 18mm of a 12mm end mill, max; less is usually wise and I normally limit it to 1.0 times the diameter if I can.

The radial depth of cut determines your speed. As seen from the chart, cutting speed goes up as the depth of radial cut goes down. To use this info, plug it into the formula: RPM = Cutting speed X 3.82 / diameter of the cutter. This works for inch calculations only, though, so you need to make the conversions. For example, if you were using a 12mm cutter and chose to engage 1/2 the diameter in a radial cut then 400 surface feet per minute X 3.82 / .5" = 3056 rpm. I suggest that you not cut deeper than 1/2 the radial depth of the cutter because your mill is not all that rigid. I would dial in 6mm depth of axial cut and 12mm radial cut and run the mill as fast as it will go. Use WD-40 or some other aluminum-specific cutting fluid and conventionally feed manually so you feel a slight resistance to the feed. The end mill cut just fine under these conditions.

Hope this helps. If it is at all unclear, let us know and we'll help you sort it out.
 

Attachments

Superslim

Newbie
Registered
Joined
Nov 5, 2018
Messages
6
Likes
2
#4
I've only been at this stuff for a year but I am lucky enough to have a 23 year old son that is an excellent machinist. He has taught me so much about this stuff.

For starters use WD40 while machining aluminum. I don't think that there is anything better that a consumer can easily get.
I'm not a stickler for speeds and feeds. I tend to do things a little slower. I don't do this to make money, although I do enjoy saving money by making instead of buying anything that I can make myself. I adjust my speeds by what the chips look like and the sound of the cutter. With a sharp endmill (but not the smaller ones) you can easily remove 40 or 50 thousandths at a time if your machine has enough power. I would start with 20 thou and go from there.
For rpms with aluminum I would turn a 1/8" endmill at 1200 rpms, 1/4" at 1000, 3/8" at 800, 1/2" at 5 or 600, and bigger cutters even slower. For cutting steel run things 1/3 slower the chips should be silver to light brown in color. Dark blue or black will ruin your endmill. If you see sparks or a loud squeek slow things down and use more cutting oil.
Like I said start slow listen to what your machine is saying, you can always speed things up as you become more familiar with things.
I hope this helps, good luck!
Thank you for the advice, those speeds seem slow, the stuff I have read say aluminium should be milled at about 2000

But like you say start slow and hear what the machine is saying

Thanks
 

Superslim

Newbie
Registered
Joined
Nov 5, 2018
Messages
6
Likes
2
#5
Welcome to HM, Superslim!

I am attaching some info for milling aluminum from Niagara Cutter below. Here, you can see that the max axial depth of cut should be no more than 1.5 times the diameter of the cutter. So, you can engage 18mm of a 12mm end mill, max; less is usually wise and I normally limit it to 1.0 times the diameter if I can.

The radial depth of cut determines your speed. As seen from the chart, cutting speed goes up as the depth of radial cut goes down. To use this info, plug it into the formula: RPM = Cutting speed X 3.82 / diameter of the cutter. This works for inch calculations only, though, so you need to make the conversions. For example, if you were using a 12mm cutter and chose to engage 1/2 the diameter in a radial cut then 400 surface feet per minute X 3.82 / .5" = 3056 rpm. I suggest that you not cut deeper than 1/2 the radial depth of the cutter because your mill is not all that rigid. I would dial in 6mm depth of axial cut and 12mm radial cut and run the mill as fast as it will go. Use WD-40 or some other aluminum-specific cutting fluid and conventionally feed manually so you feel a slight resistance to the feed. The end mill cut just fine under these conditions.

Hope this helps. If it is at all unclear, let us know and we'll help you sort it out.
Thanks for the help, wow that seems/sounds a lot of fast removal, right now for removing the bulk material I have a solid carbide 2 flute end mill, so am I correct with a little WD40 I should be able to remove about 4 mm of depth with a full 8 mm of radial on each pass at 1630 rpm, I haven't tried even close to that, not got the bottle
Thank
 

catsparadise

New Member
Registered
Joined
Nov 21, 2015
Messages
25
Likes
32
#6
I'm probably just going to repeat what's already been said, but here goes...

I started out with an SX2 mill. Probably in a similar class to the machine you have - ie. not as rigid as you'd like. Try some trial cuts in waste stock and see what sounds right. I suspect if you stick an end mill 4mm deep and take 8mm width it won't sound good and the finish would be poor. I'd start with half the cutter's diameter as the radial cut and 0.5mm as a first go, then try progressively deeper cuts. Finish off with a light cut, possibly climb milling if your machine will tolerate it, fo a good finish.

With aluminium your bugbear will be chips welding onto the cutter. The WD40 (I use paraffin - it's cheaper than the blue tins!) helps stop this happening. I found 2 flute cutters better than 4 flute for aluminium - more clearance for the chips.

Oh, and when you find the settings that work, write it down somewhere for future reference!
 

Boswell

Hobby Machinist since 2010
H-M Platinum Supporter ($50)
Joined
Feb 27, 2014
Messages
649
Likes
296
#7
the stuff I have read say aluminium should be milled at about 2000
It is not so much the RPM but the relation to RPM and Feed speed. This is called Surface Feet per Minute (SFM). Higher RPM means higher Feed speed. Lower RPM = Lower Feed Speed. Also you need to take into account the number of Flutes. Higher feed rates can cause issues with chip evacuation so lower flute count (2 or 3) works better with Aluminum if you are wanting to at a maximums speed. A mister will also help evacuate chips. Speeds and feeds will also affect surface finish so experiment for the best effect.

now for the seat of the pants method. Use WD-40 or a mister. Start slow and with small Depth of Cut (DOC). Increase speed and DOC until you are happy with the sound and feel and if you go too far then you will get chips welded to the cutter. If that happens. know the chips off and get back to work but slower. Of course you can also reference one of the online speed and feed tools such as GWizard or HSMAdvisor.
 

coherent

Active Member
Registered
Joined
Aug 6, 2013
Messages
213
Likes
168
#8
I had no idea what a nixie clock was when I read your post, so had to do a little web research. They are pretty neat. I like retro and steampunk stuff which they remind me of. Please share some photos when you have any completed projects!
 

Superslim

Newbie
Registered
Joined
Nov 5, 2018
Messages
6
Likes
2
#9
This was my last clock build but now its time to go big or go home ;)
The only metal work was the brass plate bits and one on the back where the control buttons are
Z566M.jpg
I absolutely love Frank Buchwald's Nixie Machine 11 so going to make something similar and more originally mine, I don't mind getting the idea from it but I'm not copying it.

I want my legs similar to this, these are some wooden mock ups I made so will be like this but the joints will slot inside each other and I will turn some brass screws/bolts that will hold them and then go on to design the rest of the clock using brushed aluminium and brass

IMG_6753.JPG
 

hman

Active User
H-M Platinum Supporter ($50)
Joined
Feb 17, 2013
Messages
1,802
Likes
1,424
#10
I like it! The combination of fine woodworking and retro electronics is a sight to behold.
 

Superslim

Newbie
Registered
Joined
Nov 5, 2018
Messages
6
Likes
2
#11
Thanks hman - I do like it, it looks much better in real life, the nixie tubes are just timeless and getting hard to get now, the new old stocks are running out and apart from one guy in the Czech republic Dalibor Farny who makes the huge R|Z568M tubes that I will be using in my new clock though they aren't cheap at $145 per tube and I need 6 plus the colons
 

Shootymacshootface

Active Member
Registered
Joined
Mar 17, 2018
Messages
109
Likes
66
#12
Those are really cool! I always wondered how those old readouts worked.
 
[6]
[5] [7]
Top