Finding the thred size of a 3/4in. bore Bimba piston
 

Hello,

I am trying to print a mounting for a piston on a Maker Bot(3D printer). For this i need to know how to find the size of the mounting thread of the front of a 3/4 inch Bimba(brand) piston. If anyone knows the answer or how to find it please help.

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

Look it up on www.McMaster.com or www.bimba.com -> http://www.bimba.com/Products-and-Ca...Line-Cylinder/

I believe the correct answer is 1/4-28

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

On my phone but just go to McMaster and type in air cylinder. Filter by 3/4 bore and some stroke size. Click product detail and it'll call out the thread size. Same can be done with other size cylinders.

You can also go to the Bimba site and get the same info.

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

http://www.bimba.com/Products-and-Ca...Line-Cylinder/

Fill in the information (bore, stroke, double vs single acting, etc) about the cylinder, and hit the dimensions tab.

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

Ok Thanks, McMaster helped.
And just making sure (1/2'' - 20) means that there are 20 lines of thread in 1/2'' right???

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

That is incorrect. 1/2 is the diameter and 20 is the number of threads in a full longitudinal inch.

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

Not quite.

Standard bolt sizes are notated as "diameter - threads per inch", so 1/2'' - 20 is a 1/2'' diameter bolt with 20 threads per inch.

Note that for smaller sizes, the first number may be given without units (such as "10-32"). This refers to machine screw size, (in this case, a #10), and if you want to know the diameter in inches you can just look it up (in this case, it'd be ~.19''). It helps to have a wall chart in your build space for this.

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

Oh ok well that makes more sense. Now im measuring the diameter of the piston mounting tread and from the part without thread i get .54 inches and where the thread is i get .61 inches. Does that make a difference?

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

I also feel like i need more information in order to actually draw the thread into the mounting in Solidworks. Does anyone have any ideas on how to do this?

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

Use the "Hole Wizard" tool, it has all the information needed.

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

Solidworks should have a threaded hole feature built in, where you can select the thread type (if it is actually .61 it may be a 5/8" bolt at .625)

You just need to measure the major diameter (largest diameter you can get (so include threads) and the threads per inch. Then you should be able to use the threaded hole tool. Tell it it is a 5/8 - 24 bolt (or whatever it actually is) and how deep you want the hole to go, and it will draw the threads visually.

To actually get the three-dimensional model of the threads so it can print on a 3d printer you will have to go through a complicated process of drawing the profile and revolving it in a helical manner at 1/24" per revolution.

It may be easier to print the hole to the appropriate tap size In which case you would create a hole of that size in solidworks, so it is printed, then tap the threads into it. I suspect your printer may have difficulty providing enough resolution to make clean, strong threads.

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

With my team's makerbot, we've always printed to tap into it for bolts. The default wall thickness is 2, but I like to double that to 4 layers for the taps - you want to make sure there is enough material there to hold.

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

Just to clarify, virtually every 3/4" bore cylinder I have ever used (primarily Bimba) in the United States has been a 1/4-28 UNF thread on the rod.

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

Yeah, it seems a bit big, 0.61" might be referring to either the threads on either cylinder endcap for affixing it?

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

Yup, that's a .625-18 on those cylinders.

Re: Finding the thred size of a 3/4in. bore Bimba piston
 

Bimba already has a CAD file of the Clevis you are trying to make

EDIT: well it is missing the threads, but here