# Thread: SolidWorks Question

1. BillH Guest

## SolidWorks Question

Here is what I did tonight, I designed a chip tray for my lathe. My main question is with the 4 holes drilled for the lathe, there dimensions SHOULD be 6"x 27.375, and in the Sketch they are. However, I inserted those holes when the Chip tray was already bent. For the 2d drawing, I flattened the tray. Should I of put the holes in when the tray was in the flat position? Why have my dimensions changed? I know why the others have, for the bend allowance.

2. Senior Member
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Were the holes dimensioned from the edges? If you place a constraint on the holes (distance between them in x and y directions, distance of one of them from the centerline of the part, also in x and y) I think you may get different results. Den

3. BillH Guest
the holes are dimensioned on the sketch from the origin which is smack dab in the middle. I will try the constraints tommorow. It must be calculating those holes with the sheetmetal k factor.

4. Senior Member
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The quick and dirty way to do it is to 'fix' the postion once dimensioned, the buton will appear when the sketch is being worked on, or you can use the 'add relation' tool.
Or you could put a fixed centreline line on the sketch, and use the '=' relation to put a constraint in, or dimension one hole from the centreline and then the second hole from the first.

Peter

5. Senior Member
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Am I missin sumthin? you say; there dimensions SHOULD be 6"x 27.375, and in the Sketch they are.

yet when i look at your sketch im seeing 6.100 By 27.370 ?

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Did you go outer or inner parimeters for bolt holes one way and centerline the other?

7. BillH Guest
Boomer, the 2d sketch, not the 2d sketch your looking at in the drawing, but the 2d sketch of the 3d model has the correct dimensions. Solidworks calculates stretch and shrink with the K factor on sheetmetal parts. One hole is measured from the origin with all the other holes dimensioned and relationed to the first.
Peter, I had a feeling that fix button would probably be the answer to the problem, thanks.

8. Senior Member
Join Date
Feb 2004
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127

## Fully Defined...

Having used SolidWorks almost daily since 1996 I have one piece of advice. When sketching a feature like your holes (or any other for that matter) always make sure all the sketch entities are fully defined or contrained. When you sketch the lines are blue until you fully dimension them from other lines or the origin or reference planes etc. When fully defined they turn black and will not move around on you unless you dimension to something that moves (like a bent edge in sheet metal).

The "K" factor in SW would not cause your holes to move if they are dimensioned properly. In your case you should pick the center of the tray as the base face for the sheet metal feature then the "K" will only be applied to the folded edge dimensions when flattened.

Once you get the hang of a few basics SW is a very powerful tool. You can model almost anything you can think of.

9. BillH Guest
GlenJ, I found my problem, one of my dimensions were not sitting on a flat plane, but from the 2d view, looked like it was, that was skewing my numbers.
I am now putting in a locomotive frame and having hell of a time getting all the blue lines to be defined and turned black. When you are staring at 50+ dimensions all over the place and see 1 little blue dot or line and cant figure out why it is blue, it drives me crazy! I am making headway, I will make sure all my dimensions are fully defined before I move on to the next part.

10. Senior Member
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In SE, I seldom use sketches unless creating a solid of revolution from one. In SW, do you need to have to use the sketches or can you create protrusions, holes, revolved solids, etc. in solid form? This may be one of the reasons the mech guys in our lab prefer SE. You point to a surface and either protrude a feature, create a hole or cutout, or whatever, similar to a machining operation. You can throw a dimensional constraint on any feature, enable viewing of constraints and change one while viewing the 3d part (length, diameter, etc.).

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