metal cutting part 2 (1 Viewer)

[chicago]

Hey all,
When using a chop saw, my 45* cuts are off, enough that when I weld em together, there is quite a gap that needs to be filled.
I am just finishing a cart for the welder using 1x2 in stock (not sure what gauge) and I had a hell of a time with the gaps.
Does anyone else have this problem? How do you solve it?
Right now its just a cart, but its something Id like to get figured out before I get stock for the rig and have all these SHI*ty 45* 's that need to be filled.
Is that the nature of the chop saw, or is it the chop saw that needs replacing?

Thanks,

Chicago

 

[2badfjs]

I'll use a speedy square to make sure your at 45 degree.
if your cutting two 45's to make a 90 corner, there should be no gaps.
i can see my blade float just a bit when i start a cut, not much you can do about it but wait for the blade kinda balance out before starting your cut.

i would like to invest in a drop down power hack saw myself.

BTW how big are your gaps?

 

[2mbb]

If you don't secure tight the piece you are cutting the abrasive disk can pull the metal into the disk, causing the resulting cut to be off.

 

[REZARF]

If I chop too fast the blade on mine tends to wander outward by the bottom of the cut... not sure why, but I have to take my time and allow the blade to do the work and not mash the saw down on the stock.

Rezarf <><

 

[chicago]

If I chop too fast the blade on mine tends to wander outward by the bottom of the cut... not sure why, but I have to take my time and allow the blade to do the work and not mash the saw down on the stock.

Rezarf <><

This sounds like what is happening on mine, and I might be trying to cut too fast. Ill try slowing down the cut and see if that helps!
Thanks,

Chicago

 

[chicago]

I'll use a speedy square to make sure your at 45 degree.
if your cutting two 45's to make a 90 corner, there should be no gaps.
i can see my blade float just a bit when i start a cut, not much you can do about it but wait for the blade kinda balance out before starting your cut.

i would like to invest in a drop down power hack saw myself.

BTW how big are your gaps?

2bad,
The gaps are about 1/16 to an 1/8 in! Insted of the cut being a straight, it goes diagonally on each cut, and when you but the 2 pieces together, there is a gaping hole on one end that the wire will actually shoot down into.
So Ive been filling it in, almost spot welding, stopping and cleaning the weld, then going over with a 2nd pass and cleaning it up.
Ill take pics later and post em.

Chicago

 

[chicago]

If you don't secure tight the piece you are cutting the abrasive disk can pull the metal into the disk, causing the resulting cut to be off.

2mbb,
I thought that initially, so I tightened down the stock, and still had the same issues, though not as bad.

Chicago

 

[2badfjs]

2bad,
The gaps are about 1/16 to an 1/8 in! Insted of the cut being a straight, it goes diagonally on each cut, and when you but the 2 pieces together, there is a gaping hole on one end that the wire will actually shoot down into.
So Ive been filling it in, almost spot welding, stopping and cleaning the weld, then going over with a 2nd pass and cleaning it up.
Ill take pics later and post em.

Chicago

if i have small gaps like that, i'll kinda pulse the trigger:
zaaapp, pause a second, zaaapp,pause,zaaapp.
this allows the weld to cool enough so that it does'nt molten and blow thru and make holes.

 

[honk]

If you try to cut fast it can heat the work enough to warp it or cause it to expand and then contract to a different dimension than planned. 1/16" isn't bad but 1/8" is big.

 

[Cube Dweller]

It's the blade deflecting. Measure the length of the tube top and bottom, bet it's longer on the bottom.

 

[Pin_Head]

45 degree miters aren't the best way to make 90 joints with steel tube because they are nearly impossible to get to be square after welding even if the cut is right because of bead shrinkage after welding.

The better way is to cut a square notch out of one tube leaving one wall of the tube to cover the open end of the tube that fits into the cut notch.
Weld all around. The shrinkage tends to pull parallel to the joint so it stays square after welding.

HTH

 

[LandCruiserPhil]

Try backing the gap with a scrap of very thick metal. If the scrap metal is thick enough the weld will not stick to the scrap but your gap will fill.

 

[chicago]

if i have small gaps like that, i'll kinda pulse the trigger:
zaaapp, pause a second, zaaapp,pause,zaaapp.
this allows the weld to cool enough so that it does'nt molten and blow thru and make holes.

This is how I was able to fill in the gaps, the way you described. It looked pretty crappy, but it filled in, I then went back and went over it to clean it up and re-enforce the first weld.
Im becoming rather anal about the "appearance" of the weld, and Im not sure if this is necessarily a good thing.
As mentioned, I ground down the welds, and its uniform all the way across, from true stock to the weld. In the "check my welds" thread, someone mentioned grinding down the weld was a good way to ascertain its integrity.

Chicago

 

[yzftaco]

It's the blade deflecting. Measure the length of the tube top and bottom, bet it's longer on the bottom.

X2

If you are in a hurry... at least start the cut slow, and half way thru as you have the cut metal to guide the blade.. then you can put a little more muscle into it. (not sure if this makes sense..)

 

[chicago]

It's the blade deflecting. Measure the length of the tube top and bottom, bet it's longer on the bottom.

Hey Tony,
I think "blade deflection" is what is happening here. That is what makes most sense.
Its a new blade, tight stock, clamp bolts are tight...I think Im trying to cut too fast.
Ill find out tonight and take some pics.

Thanks for the input!

Chicago

 

[chicago]

X2

If you are in a hurry... at least start the cut slow, and half way thru as you have the cut metal to guide the blade.. then you can put a little more muscle into it. (not sure if this makes sense..)

Yes,
what youre saying is..."let the metal be your guide" sort of thing.
Initially when you cut, there is no lateral reinforcement, but when you get down into the metal, the blade will be stabized by the metal.

Correct?

Chicago

 

[chicago]

45 degree miters aren't the best way to make 90 joints with steel tube because they are nearly impossible to get to be square after welding even if the cut is right because of bead shrinkage after welding.

The better way is to cut a square notch out of one tube leaving one wall of the tube to cover the open end of the tube that fits into the cut notch.
Weld all around. The shrinkage tends to pull parallel to the joint so it stays square after welding.

HTH

I can get it square, but in order to get it square, requires me to have gaps in the butt of the two pieces.

Chicago