Fitting flat head screws to countersinks

[kb9ydn]

I'm looking for a way to join a screw to a countersunk hole such that the screw stays in contact with the countersink if the countersink depth changes.  Join doesn't seem to have any options to do this that I can find.  I could use a simple offset and just fudge it to be close but that's seems pretty lame.  Does anyone have any more clever ideas?

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[mrm1018]

I'm interested in this too. Currently I just mate the flat of the screw with the "top circle" of the countersink. So with clearances, the cone countersink screw never touches the cone of the countersink.

[daniel_lyall]

If the point where the screw and the countersink meet at the bottom of the countersink is bang on you would put the joint there.

To get it to work if you change the countersink depth, you Have to get the order correct, put the countersink in.

(This get you a timeline item for the hole then the bolt so you can use the timeline to adjust the hole.)

Now places a joint origin at the bottom of the countersink. (you may not need to do this step)

Import the bolt and move it over the hole it only needs to be close, capture position of the bolt.

(have it sitting above the hole if it goes wrong it's two step to fix suppres feature then redo the joint)

Now do the joint.

when you adjust use the timeline once the adjustment is done step the timeline back it should rebuild the bolt to the joint origin, this should work it did last time I did it.

A lot of problems people have is with the order of operation, it takes a few years to get it correct 90% of the time.

[kb9ydn]

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@daniel_lyall wrote:

If the point where the screw and the countersink meet at the bottom of the countersink is bang on you would put the joint there.

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If that were the case it would be easy, but it's not.  The screw hole is larger than the screw body so the screw head and countersink don't match up.

This particular case shows why I like the mate system in Solidworks so much better than Fusion's joint system.  I could do this in three clicks.

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[mrm1018]

C,

I was thinking the same thing.  I think it's actually one mate in Solidworks if you're ok with the fastener rotating...just a coincident mate on the two conical surfaces.

[Beyondforce]

Please attach the file and I'll show you how to do it.

Ben.

[kb9ydn]

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@Beyondforce wrote:
Please attach the file and I'll show you how to do it.

Ben.

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As it turns out I decided to use a set screw instead for this particular design (it makes more sense), so I'll have to rig up another example when I get back later.  Headed out the door right now.

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[kb9ydn]

Here's a dummy example.  I need to clarify my original question though.  I know how to apply the joint so that the position of the screw changes with the size of the countersink.  What I don't know is how to apply the joint so that the screw head is fully seated in the countersink, without having to fuss with offsetting the joint.

C|

[kb9ydn]

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@mrm1018 wrote:

C,

I was thinking the same thing.  I think it's actually one mate in Solidworks if you're ok with the fastener rotating...just a coincident mate on the two conical surfaces.

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It is one mate.  And newer version of SWX have an option to lock the rotation on concentric mates, so you can fully define the position of a flat head screw with one command.  It's pretty slick.

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[daniel_lyall]

When we get driven dimensions it's just going to be a paramater. the one you use for the countersunk hole.

[mrm1018]

Waiting on you Ben!

[daniel_lyall]

@mrm1018 if you wont someone's attention use @ 

[mrm1018]

Ok, thanks @daniel_lyall 🙂

[Beyondforce]

Hi @kb9ydn,

I hope this will help:

Cheers / Ben
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[daniel_lyall]

@Beyondforce Now For the newbie who asked as well how do you adjust it so the countersink can be made deeper and the bolt moves with it.

[Beyondforce]

That's easy... Since we use the screw to create the countersink - if you move the screw, the countersink on the cylinder will change accordingly.

[kb9ydn]

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@Beyondforce wrote:

Hi @kb9ydn,

I hope this will help:

Cheers / Ben
---------------------------------------------------------------------------------------------------------------------------
Did you find this reply helpful ? If so please use the Accept as Solution or Kudos button below.

Check out my YouTube channel: Fusion 360: NewbiesPlus

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First off, thanks for taking a shot at this one!  That's an interesting and creative way to do it.  But unfortunately it only works if the screw head is completely above the top of the surface, which really defeats the purpose of a countersunk screw.  Usually you want the head to be exactly flush or below the surface.  Of course you could add an additional step to cut out the rest of the countersink above the screw, but this is hardly an efficient approach.  I was hoping for something more streamlined.

After messing around a bit it looks like offsetting the joint to match the screw head to the countersink is still the most expedient way to do this.  If you go into wireframe with hidden edges view you can see both parts from the side fairly easily and get them lined up.  It's not as efficient as a direct surface to surface joint would be, but maybe AD can work on this for the future.

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[Beyondforce]

You can move it below the surface no problem Since we use the screw to create the countersink - if you move the screw, the countersink on the cylinder will change accordingly.

[kb9ydn]

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@Beyondforce wrote:
You can move it below the surface no problem Since we use the screw to create the countersink - if you move the screw, the countersink on the cylinder will change accordingly.

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Except you get something like this:

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[TrippyLighting]

That's really not the only problem with @Beyondforce's creative approach.

I've not yet had the need to create detailed technical manufacturing drawings in Fusion 360 with GD&T dimensional tolerances surface symbols etc.

However I've done this many, many times in solid Works and often enough in Alibre/Geomagic Design. In these software packages when modeling you create the countersink hole with a hole wizard including all parameter of that countersink hole.

When creating the drawing you can with a couple of click  auto-dimension the hole and all the parameters from the hole wizard dialogue populate automatically. I don't believe such a mechanism yet exists in Fusion 360

Anyway,  the method with creating the countersink separate from the hole would undermine that functionality.