Countersinking flathead screws V13 Platinum
I'm fairly new to 3D work, and feeling pretty stupid. How do I countersink a hole in a block for a flat head screw? I can drop an 82 deg flat head screw (X-Solids) into a clearance hole, with the head flush to the surface, and "Subtract" the screw from the block. But what if I want that screw recessed below the surface, say .050 inches? I'd need to extend the screw's 82 degree conical head the exact distance necessary to recess the screw .050". There must be an easy way to do this, but my 2D brain is not helping me!
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Hi Jim:I would do this by creating a cone who's centreline is aligned to that of the hole and then subtract the cone from the body containing the hole.To create the cone draw a closed polyline which represents half of the cross section of your countersink drill bit. Note that you could draw the full cross section and rotate it 180 degrees in the next step - it's up to you.Revolve your closed polyline about it's centreline 360 degrees. You should now have a 3D cone.Use the align command to align your cone to the centreline of the hole. When using the align command, first pick the centre of the base of the cone, then click the centre point of the top of the hole, next pick the point of the cone and pick a point along the centreline of the hole (or the centre of the circle representing the end of the hole), hit enter at the 3rd point prompt and enter again at the final prompt to accept no to scale the entities.Your cone should now be placed at the top of the hole with its point pointing toward the bottom of the hole.Run the subtract command and subtract the cone from the object with the screw hole in it.Check out the video attached, it should give a bit more clarity to my description.0
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Well, the way I'd do it (caveat: there are undoubtedly better ways):
- Drop clearance-hole sized circle onto the face and push it in (or through).
- Drop a concentric circle that's the proper diameter for the head. Extrude that circle, with a taper of 41 deg and a negative height (so that it's an innie not an outie). Note that this needs to be the extrude command and not the quad's version, in order to access the taper option.
- Grab the face on the base of the cone with the quad cursor and extrude it up "far enough." Don't use push-pull here, since that would just continue the conic shape.
- Select the now pointy cylinder, move it down .050", then subtract it from the main object. Done.0 -
Thanks guys. I will give it a try.0
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Scott,
I forgot to thank you for the video. How do you create them? Is there something built into BricsCAD?
Richard,
I'm so inexperienced with 3D, I never realized there is a tapered extrude command!
I do not want the flat head screw recessed in a straight walled hole. I need it recessed in a tapered hole which would be generated by a 82 degree countersink.
Here's what I finally did. I created a circle the exact diameter of the screw head, concentric with my through hole. I extruded the conical shape down into the block, as you described. (Scott's method works just as well.) Then I used the extrude face command to extend the plug (with taper) .05" above the block. I moved the plug down .05", and subtracted it from the block.
Neat!0 -
Hi,A short tutorial movie about countersinking flathead screws in BricsCAD is available on our YouTube channel.Best Regards,Sander0
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Hi Jim:To create the video I used Microsoft Expression, it is a discontinued product (some information here: http://www.microsoft.com/expression/eng/), it is available for free on the Microsoft website: http://www.microsoft.com/en-us/download/details.aspx?id=278700
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Sander,
I was wondering if the procedure you referenced in the video works for you? I have watched the video repeatedly, and tried the steps over and over again, but it does not work on my system, either with V14.2.17 or the last version of V15.
I place two copies of the same screw in my drawing. I make a clearance hole in the block. I move one screw to the hole I just cut, and subtract the screw from the block. I am left with a countersunk hole, perfectly flush with the surface of the block.
I then apply a Fix constraint to the top surface of the block. I drop the second screw into the hole using the Coincident constraint (applied to the angled surfaces of block and screw). The screw is transported into the hole. That is where the proceedure goes south for me. Moving the screw downward DOES NOT deepen the chamfer. If the head of the screw moves the slightest, (and it doesn't always), it then snaps back to the surface. It doesn't matter if I have ESNAPS enabled or not. Bricsys support keeps telling me I must be doing something wrong, but I am damned if I can figure it out..0 -
FWIW: The procedure in the video works fine for me (V16.1.05).
Maybe there is an issue with the DMRECOGNIZE setting that can cause your problem, I am not sure.
You should post your dwg.0 -
... One thing that may be causing confusion is the snap setting.
In the video when the initial rectangle is drawn snap is on. But when the fastener is moved, after the constraints have been applied, I believe that snap is off.0 -
Roy,
Thanks for your reply. Sorry about my late response. Been out sick for a few days. I have DMRECOGNIZE set to "2". I'm not having any luck, even with ESNAPS off. I can move the fastener, but it always returns to it's original position. I've attached a copy of the drawing, if you think you can figure out what I am doing wrong.0 -
@ Jim:
Your screws are not blocks or Xrefs, but 3D solids. This is the cause of your problem.
You can do two things:
1. Create a separate screw.dwg and BmInsert it.
2. Apply a 'rigid set' constraint to the screw solid. Because the screw is very complex (the thread is a helix) this is problematic.
Attached is an example showing both methods. To demonstrate method #2 I have create an 'unthreaded' fastener.0 -
@ Jim:
Your screws are not blocks or Xrefs, but 3D solids. This is the cause of your problem.
You can do two things:
1. Create a separate screw.dwg and BmInsert it.
2. Apply a 'rigid set' constraint to the screw solid. Because the screw is very complex (the thread is a helix) this is problematic.
Attached is an example showing both methods. To demonstrate method #2 I have create an 'unthreaded' fastener."Create a separate screw.dwg"? Are you saying I place the screw I have in a separate drawing and BMinsert it? Or is there something wrong with my screw?0 -
There is nothing wrong with your screw, but it is a very complex solid. Putting it in a separate file and 'xreffing' that makes sense anyway. But this will also ensure that the screw is a fixed element which is required for the technique demonstrated in the tutorial to work. On my machine applying a 'rigid set' constraint to the screw's 3D solid did not work. My guess is that this is because the screw is just too complex.0
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... Maybe it is a good idea to retry the tutorial, following each step exactly. This means starting out with same fasteners and exploding only one of the two. This is the crucial part of the tutorial that you have skipped.0
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Over the last few years, I have created a library of fastener solids that omit most of the detail that make the existing BricsCAD library unusable for my work. Hopefully Bricsys will fix that in some future release, since they used to have the non-threaded fasteners in an older version. Though I do wish it were possible to see some sort of thread. Perhaps some sort of toggle to switch between the two types of fasteners. That may be possible with lisp, if there were some sort of consistent naming between the threaded and non-threaded fasteners.Another thing I would love to see is a hole library. I.e. choose a hole for a 1/4"-20 bolt, with a choice for Tight, Normal, or Loose fit. It is less of an issue for cap screws, but the flat head ones are a pain to do manually. I suppose I should start a library of those holes as solids, that I can insert, explode, and then subtract from the solid. But, I rarely use flat-head screws, so I don't personally have much need.-Joe0
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@ Joe; The screw in Jim's drawing does not come from the BricsCAD library. I don't think helical threads occur there.0
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............................Another thing I would love to see is a hole library. I.e. choose a hole for a 1/4"-20 bolt, with a choice for Tight, Normal, or Loose fit. It is less of an issue for cap screws, but the flat head ones are a pain to do manually. I suppose I should start a library of those holes as solids, that I can insert, explode, and then subtract from the solid....-Joe
Joe, that is a great idea. I would use that every day. And I do use a lot of flat head screws.0 -
@ Joe; The screw in Jim's drawing does not come from the BricsCAD library. I don't think helical threads occur there.
You're right Roy. I get most of my hardware models from McMaster Carr. They are a great resource for hardware and models to match. But they are full helical threads, and this does slow down my machine considerably.0 -
As much as I love McMaster-Carr for their wonderful online catalog (they really are 10x better than anything else out there), the CAD models they provide for download are generally useless from my perspective. Their screws and nuts are quite detailed, even more so than the ones BricCAD provides.A few years ago I wrote to McMaster about this, and also to Bricsys, but it looks like we are stuck with highly detailed fasteners.There are only a few screw types that I use. I wish we had 3D parametrics so that I could model a single #10-32 bolt, and then easily change its length without having to manually create each variation in length.-Joe0
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No, there isn't an easy way. On another thread, I suggested abandoning the BricsCAD fastener library because of problems with hightly detailed models for the fasteners, and incorrect naming of small screw sizes for English fasteners. There are probably only a few fastener types you use anyway.For the recessed flat-head screw you are describing, you need to model your hole 1st as a solid. Be sure to include a extruded top cylinder that will later be used to create the countersink. Also, save this solid into a directory where you can easily find it again. You would want the origin of the model to be at the center of the top of the cone shape. Note that if you insert this model into another drawing, it will come in as a block. Before you can use it to form a hole, you will need to explode it so that it will be listed as a "3D Solid".Once you have your solid that represents the hole you move it to where the hole should be and then use the solid subtract command.I will also mention that you can explode the screws from the BricsCAD fastener library, though you will get all the modeled threads as well. But, it might be a good guide for re-modeling. Personally, I prefer to go to www.mcmaster.com and find an example screw there, and view their dimensioned drawing to create a sketch that I use to create the fastener.-Joe0
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@ Joe:
You can create a single model for a bolt with a variable length. You can do this with 3D constraints and parameters. Note: you have to use BmInsert to insert the object.0 -
I have spent a fair amount of time trying to figure this out, both today and in the past. My help file will give info on specific commands, but I cannot find a "getting started" or much in the way of tutorials for mechanical for v14 (or even releases right before or after). I looked hard for anything that mention 3D constraints being able to change the dimensions of a solid. I also searched the BricsCAD TV on Youtube.Are you sure you can actually change the dimension of a solid such as the length of a bolt?-Joe0
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Yes, I am sure. For example BIM window components use this technique.
I am attaching a simplified M3 bolt sample (with the thread 'sanded off').0 -
Thank you very much for that. I will endeavor to create a library that I will share here on this forum.But, first I need to get a better handle on the mechanical part of the program. The main issue that caused my frustration may been the documentation. That, together with a few actual limitations or problems with the program pretty much caused me to abandon hope in it. But, you have rekindled my interest. Also, the fact that work is slow right now, for me means I can invest the time to learn. I will contact support to see if they can direct me to some better tutorials, even if it is not for v14 that will give me a start. Hopefully later versions improved the documentation and training videos, and were enough like v14 that I can get started.-Joe0
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