Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: Asellith on April 07, 2011, 05:42:25 PM

Title: Threading rod that needs to be perpendicular
Post by: Asellith on April 07, 2011, 05:42:25 PM

So I am trying to tap acrylic and screw a threaded brass rod into it. I'm having trouble getting them to be perpendicular when connected. I'm tapping and cutting the threads by hand. Any suggestions or tips?

Title: Re: Threading rod that needs to be perpendicular
Post by: Soeren on April 07, 2011, 06:16:06 PM

Hi,

A drill press is probably the easiest way - just turn the chuck by hand and watch the z-axis.

Title: Re: Threading rod that needs to be perpendicular
Post by: MikeK on April 07, 2011, 09:51:23 PM

Make or buy a tapping guide.  It's a block that holds the tap perpendicular to the surface it rests on.

Title: Re: Threading rod that needs to be perpendicular
Post by: Asellith on April 08, 2011, 09:19:43 AM

Thanks Soeren. About 10 mins after I posted I tried my drill press and it worked great. I used it for tapping the holes but didn't think of it right away for die cutting the rod. I just tossed it in the chuck and it worked great.

Now if I can find a source for various lengths of stainless rod with a small amount of thread on them then I will be set. Prototypes are ok but production runs of these are going to be a pain.

Title: Re: Threading rod that needs to be perpendicular
Post by: waltr on April 08, 2011, 09:56:55 AM

Threading the end of a rod can be done in a lath.
For production you may want to have a local machine shop make these. It could be cheaper when you consider your own labor cost.

Title: Re: Threading rod that needs to be perpendicular
Post by: Asellith on April 08, 2011, 10:27:09 AM

I'm going to look into that option but I don't know if I can do it for the cost I need. Just cut to length steel is pushing my price limit at roughly $0.25 a unit for 2" stainless. I'm looking into alternative parts that might work. For instance an R/C car push rod with threaded ends could work if I can find the right one and get them from a distributor without having to go through a retailer.

This is plan B because I wanted to do something with clear acrylic rods but they are not strong enough.

Title: Re: Threading rod that needs to be perpendicular
Post by: Soeren on April 08, 2011, 07:59:09 PM

Hi,

Quote from: Asellith on April 08, 2011, 10:27:09 AM

Just cut to length steel is pushing my price limit at roughly $0.25 a unit for 2" stainless. I'm looking into alternative parts that might work. For instance an R/C car push rod with threaded ends could work if I can find the right one and get them from a distributor without having to go through a retailer.

Not sure of what gauge you need, but perhaps bicycle spokes could be used - not sure how much they are in your end of the world either, but I would guess them cheaper than R/C rods.

A small shop with a CNC would probably be the cheapest, but you'd have to order enough to spread the setup cost.