[snout]

Full disclosure: I'm still very new to cutting / fitting tube and I promise to not work on anything structural for quite some time. Right now, I'm working on some basic WAL-bannable offense sliders to replace the crappy tub mounted ones that came on my JKU.

I'm working with 1.75x.120 1xxx dom tube. I'm using a HF tube notcher and so far have only been making 90* cuts. The issue I'm having is burning through hole saw blades at an excessive rate. Also, the cuts are taking longer than I would expect. My guess is I'm doing it wrong and need someone to provide some feedback on my technique.

Here's what I'm doing:
- Take measurements and mark where to cut
- Use the following formula to determine cutting speed:
(4*120)/diameter inches = drill speed
4*120/1.75=~270. My drill press' lowest speed is 300rpm.
- Coat the hole saw with dark thread cutting oil
- Apply constant (not too heavy) downward pressure and let the saw remove material. I keep the cutting edge wet with cutting oil.
- I avoid releasing pressure on the saw for the duration of the cut
- The cut takes 10 minutes or more. I've read elsewhere that it should take less than a minute. For some reason no matter how tight I have the chuck, the cutting shaft seems to drop often -- not what's going on there, but it's annoying.
- I cut all the way through the tube. I don't rotate the tube and cut from the other side

Typically, following those steps will demolish a HF hole saw about 50% of the way through the tube. A Milwaukee or Diablo hole saw will be missing 50% of it's teeth at the end of a single cut. I'm just not sure what I'm doing wrong here but it's costing me $10 every time I want to cut a tube.

I know, I know, the problem exists between the feed lever and the floor, but any tips would be appreciated. :beer:

 

[Tspevacek]

In the past I had notched many sticks of DOM with a single hole saw blade. Le the blade pull itself thru with no pressure and a constant flow of oil over the cut area. Hell I have even made holes in steel with cheap ass china hole saw bits and finished the job with a single bit, I am talking bits cheaper then Harbour freight shit.

 

[snout]

Thanks. I must be applying too much force on the feed lever or not enough cutting oil. I've been using that Oatey "dark thread cutting" oil from the plumbing aisle. I'll try again tonight when the neighbors are trying to sleep.

 

[thedirtman]

I never use oil with a hole saw and get many many cuts with a hole saw. Lately I have just been using a 5" flap wheel on the grinder as it is faster.

 

[gt1guy]

Might be a dumb question but, are you sure the hole saws you're using are for metal?

Spend 10 bucks and get a Lenox bi-metal hole saw from Lowes or wherever. They work great and are cheap. You should be able to make 20 sets of sliders from a single hole saw.

I never use oil, just a couple shots of WD40. Makes clean up easier too.

I have a JD2 notchmaster and I can make a 90* notch in 1.75"x .120 in about 10-15 seconds.

edit: What RPM are you spinning the notcher?

 

[snout]

They're bi-metal saws spinning at 300rpm.
I noticed the notching shaft has an ever so slight warp in it, which may be part of it. I'm going to try and press it flat and cut some more tonight when I get home.

 

[Uncle Sams Misguided Child]

 

[snout]

I straightened the shaft out with my press, fixed 95% of the wobble and used a little more oil and a little more feed pressure. Now it's working perfectly. I'll probably use the notcher for funky angled fitment.

I tried the chop saw technique above and cleaned up the cuts with a flappy wheel and files. That method is much faster and cleaner.

Thanks for all the suggestions / help! :beer:

 

[snout]

So just to add to this -- a lot of the issues I was having were due to my shit chinese drill press -- which was just too weak to drill through the tube. I moved my jig over to my welding table, bolted it down and used a plain old 10amp corded drill, which blows thru the tube like a hot knife thru butter.

 

[ExWrench]

Glad to hear you got the notcher working for you. :beer:

Now that the notcher doesn't suck, do you generally prefer it or the angle grinder?