Cannot select cylinder for threaded bolt contraint

[Anonymous]

Hi all, 

I would like to perform a simulation, where I need 16 bolt to fasten to a body through another body. It usually works with the first bolt, but then I can't get any of the following to work. 

It simply won't find the cylinder as a suggestion, which is does the first time. 

I can use the bolt/nut combination without problems, but that is not accurate for the object I am trying to model and simulate.

[Andrew.Sartorelli]

Hi @Anonymous

Welcome to the Fusion 360 forum! I just took a quick look at the bolt connector - threaded bolt feature and I'm seeing the same behavior that you described. I will follow up with the development team on the matter. I'll also take a quick look under the hood and see if this is simply a visualization problem, but the correct data is written into the Nastran bulk data file.

Best Regards,

Andrew

[Andrew.Sartorelli]

Hi @Anonymous,

I took a deeper look with my test model and only ran into problems when the threaded hole face was connected to the circular edge used in the initial selection. While I think the failure presents it self in a strange manner, it makes sense for it to not allow this as the the bolt would not actually be doing anything without connecting to another part. Might you be able to a share a .F3D of your model or a record a screencast of the problem? I think I might have encountered something slightly different than what you are referring to.

Best Regards,

Andrew

[Anonymous]

Thank you very much for looking into this. 

I have made a small, downloadable demo file here: http://a360.co/2gpsZLg

In this case I want to fasten the motor-model to the carbon plate. I select the edge of one of the 4 holes of the carbon plate facing away from the motor as location for the Bolt Head. Then I select Bolt subtype as Threaded Hole. Now I cannot select the cylindrical face inside the motor, only the face of the hole in the carbon plate. 

[Andrew.Sartorelli · Accepted solution]

Hi @Anonymous,

It looks like the problem appears to be the hole centers are very slightly different, on the order of 1e-6mm difference. The bolt connector feature requires that both the centers and diameters are the same. One thing you could do is re-create the holes in the combined model, rather than generating them individual in each component. I've also recommend to the development team that we allow for a slightly tolerance to allow for very slightly mismatching hole centers and diameters to have a bolt created for it.

Regards,

Andrew

[Anonymous]

Thanks @Andrew.Sartorelli

The holes in the plate were created using 3 mm circles from a sketch (made in a360, with the sketch circle tool), and the holes in the motor was created with Hole tool with 3 mm as diameter.

So on top of allowing for a bigger tolerance, maybe you could also initiate a alignment between the above mentioned 2 ways of creating holes. 

Much appreciate your looking into my issue!

//Christian

[Andrew.Sartorelli]

Hi @Anonymous,

I looked into things a little bit further. By using a cylindrical joint in the modeling environment I was able to get the holes to match up exactly with your provided geometry. I was then able to use the bolt connector without rebuilding the holes.

Please let me know if there is anything else I can help you with in the simulation environment!

Regards,

Andrew

[Anonymous]

Hi @Andrew.Sartorelli

I couldn't get the joints to work, but I don't have much experience with using joints in A360. However, remodeling the holes with the holes tool helped, and I can now use the threaded bolt option. 

Moving on in my simulation, I have another issue. I can't place the nut on a bolt through a metal clamp, clamping on to a carbon rod. Can you maybe tell why ?

The model is here: http://a360.co/2gDDWf8 for you to have a look at. Hopefully you can my threaded bolts in place in the file as well.

Thanks for all your help so far!

[Andrew.Sartorelli]

Hi @Anonymous,

Sorry for not responding sooner, I've been out with a bad cough that I just can't shake. I noticed that you had marked my post as a solution. Were you able to use joints in the second to allow you to add bolt connectors in the simulation environment or do you still need help with that model?

Best Regards,

Andrew

[Anonymous]

Hi @Andrew.Sartorelli

Yeah, marked it, because you have indeed solved parts of my issue, and I am most grateful for that. 

I still have problem with placing both bolts with nuts and bolt, using thread on the 2 metal clamp sets in the model, I linked in the previous post. I can't simple get a valid selection for the faces I need to constrain. 

I have redone all holes with the Holes tool, and made sure the holes were made from the same center-point on the same sketch, but still can't make them match precisely enough it seems.

Hope that update with a more relaxed alignment criteria will come sooner rather than later 😉

Hope you get well again soon !

[Andrew.Sartorelli]

Hi @Anonymous,

In the new model it seems to be picky, sometimes I do a joint and it lets me use a bolt and other times it doesn't. I'm going to take a closer look at the model and see if I can figure out what exactly is the issue.

Regards,

Andrew

[Anonymous]

Hi @Andrew.Sartorelli

Thank you for your continuous effort! I very much appreciate it !

Hope you find a good solution.

//Christian