[boydage]

We purchased a qty of 304 SS bars requiring the size to be perfect or at least very close but ended up with stainless bars that are 1mm too wide and 0.8mm too thick. We ordered imperial 1.125" x 0.375"

The size we have is 30.2mm x 10.1mm and we need to face off a very small amount to end up with 28.575mm x 9.53mm or imperial 1.125" x 0.375" . The lengths vary from 200mm to 600mm, the 600mm being the longest and most difficult I think.

Wondering what the nest strategy would be to take this worthless bar-stock and make it to something we can use? All I can think of is a facing operation on a mill with a bunch of vices all holding it in a row. Not being a machinist, this is all I can think off. Does anyone here have a better way that we can fix this issue? Such a small amount we need to remove. The current finish also on this product is quite scratched and rough. Does that make it easier?

The final finish needs to be excellent cosmetic almost polished SS. I am unsure what to do, My employer is annoyed I got this order wrong. Help?

Rgds in advance.

[Jim Dawson]

Vices is the best solution I think.

[mactec54]

We purchased a qty of 304 SS bars requiring the size to be perfect or at least very close but ended up with stainless bars that are 1mm too wide and 0.8mm too thick. We ordered imperial 1.125" x 0.375"

The size we have is 30.2mm x 10.1mm and we need to face off a very small amount to end up with 28.575mm x 9.53mm or imperial 1.125" x 0.375" . The lengths vary from 200mm to 600mm, the 600mm being the longest and most difficult I think.

Wondering what the nest strategy would be to take this worthless bar-stock and make it to something we can use? All I can think of is a facing operation on a mill with a bunch of vices all holding it in a row. Not being a machinist, this is all I can think off. Does anyone here have a better way that we can fix this issue? Such a small amount we need to remove. The current finish also on this product is quite scratched and rough. Does that make it easier?

The final finish needs to be excellent cosmetic almost polished SS. I am unsure what to do, My employer is annoyed I got this order wrong. Help?

Rgds in advance.

Depends where you are located you would be best to have it double disc ground that will be the only way to keep it flat, milling such a small amount off the parts will move all over the place, your boss needs to understand that bar stock comes in a nominal size can be +/- .050 and anything in between, see if you have a company near by that has double disc grinders TCI are quite good at this if they are near you but there are many companies that have Double Disc Grinders

You could mill the sides no problem but the face will be a challenge to mill

[boydage]

Thanks. Ok good lesson to learn. A double disc grinder. So these pieces are for the medical equipment industry. We have in the past had these parts made in a machine shop as we are only setup for alloy.

I wonder if it's worth investing or at least investigating the purchase of a grinder? What are we looking at for a reasonable one? Or even second hand?

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[boydage]

Oh they look gnarly. I'm already in the process of pushing for a 5 axis machine this might be a bit too much lol

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[boydage]

Guys so these pieces are relitively small on size. Is it something that a surface grinder would be able to do? I am looking at a few they range from $5k to lots of $$

Its a case where I might be able to swing a $5-9k machine as we do this a lot.

[mactec54]

Guys so these pieces are relitively small on size. Is it something that a surface grinder would be able to do? I am looking at a few they range from $5k to lots of $$

Its a case where I might be able to swing a $5-9k machine as we do this a lot.

Surface Grinder no that would not work, 5 axis mill that would need someone who could program it and run it

You are better off to contract someone with a double disc grinder this would clean up both sides at the same time then you get almost zero warping of the plates, if you do just one side then the plates will be like a banana unless you can straighten the plates after machining, why not change the design to suit for material that is available

[boydage]

I did wonder how much that bar would banana. I think your right we will search out a business with a double grinder.

The 5 axis was not in reference to this job. I reckon with a bit of time I could run it. As for design unfortunately we can't change it. The bars are an assessory bolted on the sides of a piece of equipment that accept many different other sub assessories that slide on and clamp tight. Hence the need for the exact size. The equipment we have purchased has come with a Euro size (much thinner and wider) we need to make it American size.

It's a small but difficult problem that I didn't take into consideration that purchasing ss bar it might arrive 1-2mm larger than ordered. My bad. We live. We learn. Thanks for your input.

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[joeavaerage]

Hi,
304 SS is austentitic and generally not considered to be magnetic. As the material is rolled and/or worked however. the strained material becomes increasingly magnetic.
In fact its a good test of SS, if its non magnetic, or only very weakly magnetic, then the material has suffered minimal strain since it came from the furnace. If its more strongly
magnetic then its had significant work, say thread rolling or thread cutting say, since it came from the furnace.

It just may be possible that it is sufficiently magnetic that you could hold it in on a magnetic base vice in a surface grinding machine, and a surface grinder will get you the accuracy and finish you want.

Craig.

[mactec54]

Hi,
304 SS is austentitic and generally not considered to be magnetic. As the material is rolled and/or worked however. the strained material becomes increasingly magnetic.
In fact its a good test of SS, if its non magnetic, or only very weakly magnetic, then the material has suffered minimal strain since it came from the furnace. If its more strongly
magnetic then its had significant work, say thread rolling or thread cutting say, since it came from the furnace.

It just may be possible that it is sufficiently magnetic that you could hold it in on a magnetic base vice in a surface grinding machine, and a surface grinder will get you the accuracy and finish you want.

Craig.

You are dreaming again and obvious have never done this type of work

[boydage]

That a fact! I always thought it was due to the quality. Hey so I have made some enquires around NZ. Craig your in the country, do you know anyone with a double grinder? I found one outfit in Akl but Google is more about advertising these days.

This stock is directly out of factory China its pretty raw.

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[joeavaerage]

Hi,
most Tool and Die makers would have one, really depends on size.

I had my smaller stuff done by Torks Precision Engineering in Christchurch, but that's only one place, there'd be dozens of others.
The real question is the material sufficiently magnetic for it to be held in the grinder? You really don't want this stuff flinging out of the machine!
May I suggest taking it to one of them and asking, it all comes down to workholding, if you can hold the work then you can grind it flat as you please.

I did a Google search a while ago and there was a company in Auckland that had a machine with 2.5m travel. I rang them and they were more than happy to do the work I wanted.
Sorry, can't remember the name.

In the event I had a company in Christchurch mill my axis beds on a big Okuma and when I measured them up they didn't need grinding....they were as flat and
parallel as I could measure.

Craig

[mactec54]

Hi,
most Tool and Die makers would have one, really depends on size.

I had my smaller stuff done by Torks Precision Engineering in Christchurch, but that's only one place, there'd be dozens of others.
The real question is the material sufficiently magnetic for it to be held in the grinder? You really don't want this stuff flinging out of the machine!
May I suggest taking it to one of them and asking, it all comes down to workholding, if you can hold the work then you can grind it flat as you please.

I did a Google search a while ago and there was a company in Auckland that had a machine with 2.5m travel. I rang them and they were more than happy to do the work I wanted.
Sorry, can't remember the name.

In the event I had a company in Christchurch mill my axis beds on a big Okuma and when I measured them up they didn't need grinding....they were as flat and
parallel as I could measure.

Craig

It does not have to be magnetic to grind it on a surface grinder I do aluminum brass and may different plastics on a magnetic table

Here is a snip of some Brass parts that where Ground on my Surface Grinder using the mag table