I was wondering if you fine folks here could take a look at my model and the attached image to see if you think the model is correct. The top view looks correct in my model but the front view is a little confusing. I'm not sure what they are trying to do with the 11/16 radius and the two radii and how they are even created.
Any help is greatly appreciated!!!
Chris
Here are my notes:
1) Your thread length for the Pipe thread tap is at the maximum. Not really a problem, just thought I would point it out.
2) Looks to be a "cup" inside the flange. You are missing this entirely. It has an 11/16" radius going to a flat that is 3/16" away from the main flat of the flange. It is hard to tell what is going on with the "R" that I am pointing to, but it might be a just showing you that there is a radius to transition into to the 3/32" cut away in the flange.
3) The thread relief for the 1/2-13 thread doesn't seem to go deep enough. The minor diameter for 1/2-13 thread is approx. .404" (for 2A fit). Your part follows the print, but I don't think it is enough.
I could have sworn I put the 11/16 radius in there. Maybe it was suppressed?
Chris
Christopher Estelow wrote:
I could have sworn I put the 11/16 radius in there. Maybe it was suppressed?
Chris
Yes, it was suppressed. That is why I didn't include it in my notes.
Christopher Estelow wrote:
front view is a little confusing. I'm not sure what they are trying to do with the 11/16 radius and the two radii and how they are even created.
Yeah, I am not sure either. Can you get a sample part to look at/hold in your hands? I find that this sometimes helps a lot with these old drawings.
I tried to figure it out, and even tried to google some similar pins.....but no luck. Kind of reminds me of a cam mechanism to raise and lower that pin.
I wish I did have one to look at, it would make my life a lot easier. It is actually a core for a brush to clean to rocket tubes shown on the side of a Huey below.
Chris
Basically a bigger more complicated version of this
Chris
The 11/16 Rad does not go to a sharp outer corner and does not have a flat at the bottom like you modeled in your part file. Instead, it is a spherical radius as shown by the center tick just before the dimension arrow jog. This can be confirmed by looking at the 2 concentric outer circles in the left end view although these circles are not accurate representation. Also, the top view implies .1875 depth over 270 deg. which is .250 helix pitch not .1875 like you have.
Assuming that the 9/64 x 3/32R cam surface is machined with an end mill, the attached file shows one way how this can be done. I believe the R dim is showing poor practice of trying to define the corner radius on the end mill blending from the cam surface to the .540 dia. surface.
M.B.,
I totally agree about the 11/16 spherical radius. I was a little lost when you said the 270° for the helix because I assumed it was a full revolution. I looked at it a little closer and realized that the line on the top view was straight and not on an angle. The angled line next to it was giving me an optical illusion and threw me off. I revised my model but I kept the height at .1875 and just changed the revolutions to .75. That way if anyone goes to edit the model in the future they won't wonder where the heck did he get the .25 height from!!!
Thanks so much for your input on this one M.B.!!
Attached is my latest attempt (SW15). Let me know what you think.
Chris
Anyone have any thoughts on the latest model?
Chris
Take this with a grain of salt, since I don't think that I would know how to model this part any more than you, considering the horrible-ness of the view and the dimensions.
You seem to be missing the radii for the "R" dimension....however, since there is not a dimension, not really sure what this would be.
And the drawing seems to imply that there is a sharp corner around this area. You have it with a radius.....but again, not really sure what else I would do about it.
Dan,
You don't ever have to worry about offending me with any critiques of my work. After all, if I am asking about it here it is because I am not sure if I did something right or just don't have a clue how to. For the "R" dimension I have no clue what the top arrow is supposed to be pointing to. I think it might be where I have Fillet6. For the bottom one, I believe it is referring to the point at which the swept helical cut intersects the cylindrical boss where I have Fillet5. I totally agree about the sharp corner on the other one. I attached my updated model for review.
Thanks for the help on this one!!!!
Chris
Are we all in agreement that the view on the left hand is completely wrong showing the concentric circles?
Chris
Sure...
You know, we deal with this sometimes....but what we have to do is ask the customer more questions. Normally we deal with this because our customer is taking something that they have been making themselves for 40 years or so and giving the project to us. Of course, they figured out all the issues with the part 40 years ago and never had to deal with it again. Can you ask your customer for a sample part? Excuse could be because of the confusing issue on the drawing.
Unfortunately we are going to be making the parts and there are none available to check out.
Chris
How about the mating part? Or going out to buy an assembly with this already in it? This can't be a new part. That drawing is 25 years old at least.
We are making the entire assembly. I tried to find one on the market and nobody has one available. I really do not think it is that critical as all it does is hold a spiral wound brush in place and then a nut goes on the top to hold it on. I just like making my models correct.
Chris
I am just going to run with what I have. I believe it is accurate and will serve the form, fit and function it was designed for.
Thanks for all the help on this one, it is greatly appreciated!!!
Chris
The 11/16 Rad does not go to a sharp outer corner and does not have a flat at the bottom like you modeled in your part file. Instead, it is a spherical radius as shown by the center tick just before the dimension arrow jog. This can be confirmed by looking at the 2 concentric outer circles in the left end view although these circles are not accurate representation. Also, the top view implies .1875 depth over 270 deg. which is .250 helix pitch not .1875 like you have.
Assuming that the 9/64 x 3/32R cam surface is machined with an end mill, the attached file shows one way how this can be done. I believe the R dim is showing poor practice of trying to define the corner radius on the end mill blending from the cam surface to the .540 dia. surface.