Drill Alu....

[Jameshow]

I'm making a couple of router planes.

I have 2 X 2" holes to drill in 6mm plate 6000 series.

I have a decent hss hole saw but it keeps clogging and welding alu to the teeth.

Am I going too fast too slow? I'm on a medium speed I'd say.

What cutting fluid should I use. Some wd40 perhaps?

Cheers James

 

[Jelly]

If there's chip welding, you're either running the drill too fast, or not applying enough feed pressure, potentially some combination of the two.

Cutting fluid will help, WD is not ideal but might work for Alu as might 3-in-1 or another straight to mineral oil, a dedicated cutting/tapping compound like Trefolex would be my choice but it's expensive if you only need it for this.

Hole saws generally can be funny around chip extraction, a proper trepanning tool or a just using a 2" twist drill would be better options, but only worl if you have a machine to run them in.

 

[Jameshow]

If I apply too much pressure it stalls?

Will try 3-1 oil.

Perhaps the belt is loose?

Cheers James

 

[Terrytpot]

The snag with holesaws is there's no way for the swarf to escape past the blade unless you manually lift during the cut but by the time you do so it may have already been squished onto the blade..if you just take a light score at the start marking out where the blade is going to cut and then drill a few largish (10mm or so) holes within the scored cut area that just intersect with the scored line,the swarf will have a means of escape when you continue the cut with the hole saw without having to keep lifting and also without getting squished onto the saw blade
edit: I also recall we used to use paraffin as a cutting lubricant on aluminium, just don't get stuff too hot

 

[Phill05]

Now before you all start laughing I have found Baby oil the best to use on aluminium make a clay wall around where you want to cut and pour some in swarf will not stick, the only problem I found was getting some unsuspecting person (not me) to go and get a bottle of oil to use, I am told they give you a funny look when you ask for a bottle.

 

[Davey44]

Hi there. If you're still having difficulty in getting your 2" holes cut into aluminium, then find a local hobby machinist. They'll be able using a milling machine or a lathe to bore those holes in a matter of ticks. If all else fails then contact me with your email address and we can discuss getting it done for you.

 

[Jameshow]

Hi thanks for the offer.

I used gt85 as a lubricant and with a belt change (far to fast) I had no further problems.

See my DIY router plane thread.

Cheers James

 

[Ttrees]

Are you keeping the waste?
I'd drill a wee escapement hole on the inside of the trench for the swarf to go into.

 

[Davey44]

Hi thanks for the offer.

I used gt85 as a lubricant and with a belt change (far to fast) I had no further problems.

See my DIY router plane thread.

Cheers James

Well done! Experimenting often helps, but advice from someone who's done it before is better!

 

[AES]

Well done mate. For the future (I've only just seen this thread, sorry):

1. WD 40 will work fine on ali - paraffin is the "proper" cutting lubricant. No need to buy anything expensive - but I must say I've never tried baby oil! That's a new one on me - perhaps they didn't have it readily to hand when I was doing my apprenticeship in the RAF!

2. As already said above, hole saws are a bit of a so and so for this sort of job - not a lot of set and teeth quite shallow. For a start the chip clearances aren't great on most (if not all? hole saws, and then you have the annoying problem of the fact that when being cut, the chips have strong tendency to "weld" themselves to whatever cutting tool you're using. So a trepanning tool would be better if you have it. But especially if forced to use a hole saw, you need:

3. Gentle down feed pressure, NOT heavy IME;

4. Slowest speed you can dial/set up;

5. VERY frequent chip clearing, especially with the hole saw - SO be almost constantly (every couple or three revs of the tool) lifting it fully clear of the job to clear chips;

6. Finally (it wouldn't apply in the case of your router base because it's quite thick) but if there is a next time, and if the ali is thinner, try clamping it to a sacrificial board (bit of ply or MDF off cut).

HTH (IF there's a next time).

 

[Jameshow]

Thanks that's the very conclusions I came to in the end.

Many thanks

James

 

[Sideways]

Make a good template and it will be easy to mill out a 2" hole using your 1/4" handheld plunge router.
Go in gently a mm or so at a time while you maintain a steady cut following the template.
A shortish straight bit of 6 to 8mm will be stiff enough
Dial the speed down for this. You won't be feeding the router into the metal very fast so I would run close to the bottom end of your routers speed range.