radius cut smoothing

[arrow]

What is a good tool to smooth out a 1 1/8" inside radius cuts made with a torch in 3/8 metal plate? Hand filing is getting old rather quickly. Do not have a drill press able to handle this diameter.

 

[Shield Arc]

I always use a die grinder with a roto burr.

 

[yomax4]

I agree with the roto Carbide burr. Double cut. Next would be a flap wheel on the die grinder.

 

[Brushhill dave]

Cone stone hands down

 

[arrow]

Went to Lowes and picked up this Kobalt tool as it was the only rotary tool I could find there. It worked best at slow speed in a variable speed drill. Took about 5 minutes so its slow but gets the job done. As they are only about 4 bucks, I could by several to finish th job. They also work plastics and wood of course.
Thanks for your advise.

 

[Hooked_on_HP]

If I want it smooth I use a drum sanding roll.
Bill

 

[lstinthot]

I guess I have a long way to go cutting with the torch, my cuts look too jagged to be useful. I stopped cutting with the torch and find some other way.

 

[Mace Canute]

Making a template to help guide the torch will smooth up the cut a great deal as compared to hand held torch, unless you have a very steady hand.

 

[jake98]

Went to Lowes and picked up this Kobalt tool as it was the only rotary tool I could find there. It worked best at slow speed in a variable speed drill. Took about 5 minutes so its slow but gets the job done. As they are only about 4 bucks, I could by several to finish th job. They also work plastics and wood of course.
Thanks for your advise.

Five minutes doesn't seem slow to me, for what you're grinding there. What are you making, a quick-hitch?

 

[arrow]

5 minutes was to finish up the hack job I did with the file which did most of the rough work. (over a half hour) They are brackets to go on top of a loader bucket to hold bar type forks. This way I can load and unload the forks w/o getting off the tractor as I have only a pin type mount for the bucket. The torch was used only for the radius as I could not get in there with the sabre saw. The right drill press would have eliminated this problem all together.

 

[jake98]

That looks like plasma cutting territory, you should get Mark away from his BBQ long enough to give you a quote :laughing:
I have a pin on bucket too, and the more I hear about the QA problems, the gladder I am. That looks like a good idea you've got there.

 

[deereman75]

I would have likely wore through it with a hole saw. Seeing as I have the torch skills of an Orangutan...

 

[arrow]

I would have likely wore through it with a hole saw. Seeing as I have the torch skills of an Orangutan...

A holesaw? They have that for metal this thick? When at Lowes, I did see this drill attachment that had 4 carbide teeth welded to a collar. Didn't know what it was for but it looks as if a good drill press was needed.

 

[deereman75]

A holesaw? They have that for metal this thick?

Probably not, thats why I said wore through.

 

[Gary Fowler]

The best tool for that is a high speed die grinder with a carbide burring tool. I have several of different configurations and diameters that I use with my high speed drills since I burned up my die grinder and havent replaced it yet. They work best at high speeds and light pressure rather than the low and medium speed with likely lots of pressure as you were using on the drill. Since my die grinder burned up, I havent found enough instances of needing it to replace it. Maybe Harbor Freight will have one on sale soon.

 

[jake98]

Grizzly has a few, I just ordered an 'industrial' one :laughing: for $19.

 

[deereman75]

I bought a CH one at home depot. It works great, but I later found out that that harbor freight and princess auto have the same one for way less.

 

[TRR]

If you're only doing a few holes, a hole saw should work. The technique is to go slow and keep the cut clear of chips. See the technique from the "Welding Web forum" post #13 in this thread: Drilling 1" Holes, in 1/4 inch steel - WeldingWeb - Welding forum for pros and enthusiasts

The best would be to use an annular cutter - this one is 2" but I've heard they're made up to 4". 2" Dia x 2" DOC x 3/4" Shank M35 Cobalt Fully Ground Finish Annular Cutter | Fastenal

 

[AKwelder]

torches still work, just get some more practice. Most people just fire up and cut the steel. But for finer work try this
- Grind the scale off the front and back
- Remark and even set some punch marks for following your line
- clean your tip and set the regulators until you have a 12 inch long feather when you pull the O2. It needs to be fine and long.
- Use a good clean dark lens
- Lots of Pre-heat, and then some more.
- Get comfortable at the END of your cut and then move to the start of your cut. You will always cut better moving TOWARDS your comfort zone.
- They sell nice radius cutters that hold the torch and guild it. The better ones set to a punch hole and use a magnet

The torch set up has been around a long time and is still in every shop in the country. It works.

Good luck,

 

[jake98]

torches still work, just get some more practice. Most people just fire up and cut the steel. But for finer work try this
- Grind the scale off the front and back
- Remark and even set some punch marks for following your line
- clean your tip and set the regulators until you have a 12 inch long feather when you pull the O2. It needs to be fine and long.
- Use a good clean dark lens
- Lots of Pre-heat, and then some more.
- Get comfortable at the END of your cut and then move to the start of your cut. You will always cut better moving TOWARDS your comfort zone.
- They sell nice radius cutters that hold the torch and guild it. The better ones set to a punch hole and use a magnet

The torch set up has been around a long time and is still in every shop in the country. It works.

Good luck,

that one sounds like it's worth the price of admission right there.