I need to find a low deflection rectangular steel tube

In summary, a 1"x.5" rectangular tube .065" wall and 84" long steel tube that will have the least or very low deflection is what I need. I have been trying to educate myself today on the different grades of SS which would be preferable for rust resistance. If I understand things correctly 304 SS is the most common but apparently it is more deflective than carbon steel. I have tried what I believe to be a mild 1x1.5x.065 carbon steel in my application and found it deflects too easily. I am concerned 304 SS will be worse. I can use either carbon or stainless (prefer stainless) and increase the wall thickness to .125" but would prefer not to for
  • #1
iakobos
4
0
What I need is a 1"x.5" rectangular tube .065" wall and 84" long steel tube that will have the least or very low deflection. I have been trying to educate myself today on the different grades of SS which would be preferable for rust resistance. If I understand things correctly 304 SS is the most common but apparently it is more deflective than carbon steel. I have tried what I believe to be a mild 1x1.5x.065 carbon steel in my application and found it deflects too easily. I am concerned 304 SS will be worse.

What I can't change is the requirement for 1"x.5" 84" long. I can use either carbon or stainless (prefer stainless) and increase the wall thickness to .125" but would prefer not to for weight reasons. Specifically, I need the tube to be more rigid and stay very straight and I need suggestions on which grades of carbon and stainless steel will work better.

What I am working on is a new invention. I install steel roofs. Roofs with hips and valleys require a miter cut with a circular saw on steel roof panels that are 39" wide. Miter cuts may easily range up to 60". I've invented a Miter Table (pat. pend.) that makes the task much easier. My prototype is entirely aluminum. The miter assembly consists of two rails under the roof panel that support the panel and two rails above the roof panel that support and guide the circular saw. The aluminum I used was stiff enough to not deflect but it creates too much drag on the aluminum base of the saw making it harder to push. That is why I'm switching to steel.
 
Engineering news on Phys.org
  • #2
Metal on metal can have high coefficients of friction, making it harder to push one metal item over another. I assume your frame is not painted or coated.

I don't know much about your device, but would it be possible to coat it or lubricate it in some fashion? For instance, if the frame were coated with plastic or painted with epoxy, the change in friction might be such to reduce the effort required to push the saw.
 
  • #3
Painting or coating is certainly a possibility. That's another avenue I may experiment with. Part of the problem with aluminum on aluminum, in my application, is even if one surface is painted, metal shards will be thrown between the base of the circular saw and the rail it glides across. My concern is the steel shards will still dig through a coating and cause problems. To negate this issue would require a very hard coating. I've thought of chrome as one possibility but am not sure how feasible it would be to have it done.
 
  • #4
iakobos: Any steel (including carbon steel) and any stainless steel (including SS 304) will have approximately the same deflection. Carbon steel is only approximately 4 % stiffer than stainless steel. No noticeable difference. You can call them equal. There is nothing else economical that will be stiffer than carbon steel or stainless steel 304. Either one of these is your best choice; and they are essentially equal in stiffness. Therefore, use whichever one you prefer.
 
  • #5
nvn, Thanks for the info. Since 4% is not that much different, that gives me relief to go ahead with SS. From what I can tell no other SS grade is commonly available in my size requirement.
 
  • #6
Use a piece of HDPE (high-density polyethylene) between the guide and the base of the saw. The saw will slide very easily.

HDPE is pretty easy to find, and it can be cut and drilled with common woodworking tools.
 
  • #7
Thanks pantaz, I'll look into it.
 

Related to I need to find a low deflection rectangular steel tube

1. What is a low deflection rectangular steel tube?

A low deflection rectangular steel tube is a steel tube that has been designed to resist bending or flexing under load. This means that it is less likely to deform or change shape when weight or pressure is applied to it.

2. Why do I need a low deflection rectangular steel tube?

You may need a low deflection rectangular steel tube if you are constructing a structure or machine that requires high precision or stability. This type of steel tube is commonly used in applications such as building frames, bridges, and machinery.

3. How do I determine the appropriate size of the steel tube?

The appropriate size of the steel tube will depend on the specific application and the amount of weight or pressure it will need to support. Factors such as the length, width, and thickness of the tube will need to be considered in order to select the best option for your needs.

4. What are the benefits of using a low deflection rectangular steel tube?

One of the main benefits of using a low deflection rectangular steel tube is its ability to withstand heavy loads without bending or flexing. This can result in a more stable and durable structure or machine. Additionally, this type of steel tube is often more cost-effective and efficient compared to other materials.

5. Where can I purchase a low deflection rectangular steel tube?

You can purchase a low deflection rectangular steel tube from various steel suppliers and manufacturers. It is important to ensure that the supplier you choose offers high-quality products and can provide the specific size and specifications that you need for your project.

Similar threads

  • Mechanical Engineering
Replies
2
Views
2K
  • Mechanical Engineering
Replies
8
Views
2K
Replies
3
Views
1K
  • Mechanical Engineering
Replies
6
Views
16K
Replies
4
Views
2K
Replies
6
Views
4K
Replies
3
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
9
Views
10K
Replies
1
Views
10K
  • General Engineering
Replies
6
Views
5K
Back
Top