Group Sourcing Metal Ideas

[Johnwa]

Thanks guys. I have been cutting the 1/2 x 2.5" alum that I used for proto-typing the piece needed with my "cheap Chinese" 5 x 6 bandsaw" with a bimetal 14 tooth blade and it takes almost 5 min. to cut that. I will certainly be sourcing out a much courser toothed blade.

I’ve got the same setup. I’ve never timed it but I don’t think it should take anywhere near that long. You might want to check your speed and pressure adjustment

Ok, I went out a cut a piece of 1”x3/4”. It took 40 seconds. I’m running mine on the middle pulleys.

 

[Smi_tty]

Im looking for some steel stock right now - did you guys already make a group purchase?

 

[Janger]

yes.. a year ago! LOL. Sorry. If you're in Calgary though Steel Inc is good.

 

[Smi_tty]

Jeez i must have missed the 2019 part!!!! Lmao all good.

 

[YYCHM]

Here is the final result - same as posted online at federal. the 2" square was quite a bit more per pound than the other material.

Anyone try turning the 1" round we got with this group buy? I finally tried turning some today and it's fighting me to produce a decent finish. I tried different speeds, different tools and still not great. When I faced my test piece it was as if the first 1/8" or so was some sort of hard crusty stuff and it didn't turn nicely until you got past that.

Craig

 

[Tom Kitta]

Its hot rolled soft steel - the only way you can get semi decent finish with that stuff is to use some emery cloth. I guess you could also try to partially harden the steel and then turn - I have seen parts that were welded harden considerably (relative to original i.e. maybe 25) and produce nice shiny finish.

The hard crusty stuff is mill scale.

 

[RobinHood]

I take it you are talking about 1018 hot rolled mild steel?

The outer surface is mill scale; it is a little harder than the main stock material. Usually get a pretty good finish if you have a depth of cut that is 2x the thickness of the mill scale - chips tend to break easier as well. Underneath, 1018 is ”gummy” and has a tendency to “smear”. The way around that I found is deep cuts (50 thou or more per side) and heavy feeds with, of all things, tools that work well for Stainless. Lubrication, or not, seems to make no difference. If you need a very shallow cut to finish to size, use a HSS shear tool. It will give a good to great finish, but the chips won’t break (you’ll have a very fine threaded birds nest). Not really a problem as you are only taking 1/2 to 1 thou DOC.

 

[YYCHM]

I should be past the mill scale by now......

It's defeating the HSS tool I'm trying to test, but that could be a tool geometry issue. I had to resort to carbide tooling to get this far. The finish sucks.

 

[Tom Kitta]

There seem to be vibration issues and/ or dull tooling in few areas as well as too fast of a feed for the speed.

What I though you meant is that the finish is "dull" i.e. non shiny.

Check that your tool is not rubbing on the piece.

 

[Janger]

Tom is right -tool height check your tool height on center. Check your dead center is still engaged into the work. from the picture it might be backed off a bit? Does the hole match the angle of the dead center? Just using a regular drill bit it will not match.

What speed are you turning at with the carbide? 4 * 400 / 2 = 800 rpm so at least 800. I would try 1200 or even more. Are you using auto feed? Is the tool bolted in tight and the tool post locked in place?

 

[YYCHM]

Tom is right -tool height check your tool height on center. Check your dead center is still engaged into the work. from the picture it might be backed off a bit? Does the hole match the angle of the dead center? Just using a regular drill bit it will not match.

What speed are you turning at with the carbide? 4 * 400 / 2 = 800 rpm so at least 800. I would try 1200 or even more. Are you using auto feed? Is the tool bolted in tight and the tool post locked in place?

Every thing is set up properly, every thing is tight, everything has been re-checked 3 times now. I'm using the power feed at the slowest feed rate the machine can go. I have tried 500 RPM and 900 RPM.

This is the best pass so far. The finish looks dull and grainy as if the metal it self has a grainy structure to it? As I said before when I faced the piece off the first 1/8" or more had something odd going on with it, almost crusty.

Just wondering if anyone else that got some of this stuff with the group buy experienced this. Haven't had any issues with the 1.5" round we picked up, but that stuff looks completely different than the 1" round.

Craig

 

[DavidR8]

Have you tried using a HSS bit instead? I get a better finish with HSS on run of the mill steel.

 

[YYCHM]

Have you tried using a HSS bit instead? I get a better finish with HSS on run of the mill steel.

This stuff just defeats a HSS tool or so I think. The whole reason I'm playing with this piece of steel was to check the performance of a HSS tool I ground from scratch. I had to abandon that exercise and switch to carbide to get this far.

 

[Tom Kitta]

Your dull grey finish is standard stuff when dealing with hot rolled stuff - your 2nd picture looks normal. You may get maybe a bit better finish if you up the speed a lot - i.e. for under 1" at least 1500 rpm. With soft hot rolled with say 7/8 you may even go 2000rpm or more depending on carbide.

 

[Dabbler]

I'd even try 200 rpm for a 1" piece. Now that the scale is off you can go back to HSS. The scale is pretty hard, but the steel is soft underneath. The softness leads to the pits and grains. As Rudy says, using a diamond ground carbide intended for gummy stainless (like 304, your finish will improve a lot.

If you use HSS grind the bit as for stainless, that is a much sharper point, in the 8-9 degree angle, with at least 7 degree back rake.

But your very best finish on these soft gummy materials is to use a shear tool. I don't have one yet, but it will leave a very nice finish.

Xynudu on Youtube shows how to use a shear tool on the same kind of steel:

if you prefer Mr Pete222, here's another:

 

[YYCHM]

Ok..... 180 RPM and HSS produced an acceptable (actually quite decent) finish with a 0.015 pass.