Doorway Chin-Up Bar Modification

A sound mind in a sound body... Keeping it that way is a big job especially for those who spend most of the time working with computers, but I'm still kicking. About a year ago I bought a doorway chin-up bar which had some imperfections I found possible to fix.

The exact item I bought at Amazon.com is not in stock any more, but there are many other similar pull-up/chin-up bars available from different manufacturers. For instance:

or

They may come in different quality and price and it is difficult to suggest any particular one without trying. I usually rely on reasonable comments from other buyers. As a reference - I got my chin-up bar for about $40...45 and it has been working well for all the time.

To my point of view there are two main drawbacks in the construction of the most of these chin-up bars:

1. They have relatively short and narrow plank which goes against the wall above door. With a body hanging and convulsing on the bar, the plank applies too big pressure to the wall and leaves marks. To resolve the issue it is necessary just to make the plank a little bit longer than width of doorway. Also in this case the plank will rest on three vertical wall studs, not just one: the first one is in the middle above door and other two - at doorway sides.
   
   
2. For my height I'd like the chin-up bar sitting in the doorway as high as possible and it is feasible - it's just necessary to screw properly the plank (or "wall bar") to the rest of the chin-up bar assembly.
   

Just to illustrate the idea I have drawn the original and the modified chin-up bars:




For those who wonder: all the parts and assemblies were done in Alibre, a mechanical 3D CAD tool, and printed out into 3D PDF, so one can click the image and get 3D control over the part. Whole collection of the Alibre files for the assemblies can be taken from here.

While it is easier to do accurate mechanical drawing with a 3D CAD software, SketchUp is more convenient for quick modeling. I've uploaded the models to 3D Warehouse: the original bar, the modified one and comparison between the both chin-ups on doors.

In practice the task is pretty simple:

1. Buy a piece of wood: width is about 1 cm smaller than the gap between top door casing and the ceiling, slightly longer than door horizontal dimension, and the same thickness as the original plank (in my case the new plank was 94cm x 14cm x 2cm).
   
   
2. Position the new plank in the proper place above the door, temporarily secure it there, for example, with masking tape - do not let the wood fall on your head!
   
   
3. Then position the chin-up bar assembly without the original plank - ask someone for help to hold it in place for a while. Mark the location of the mounting holes on the plank, then drill the holes: make them of "counter drill" type to hide screw head below the plank surface.
   
   
4. Assemble the chin-up bar, add some soft material to the side of the plank which faces the wall to protect it even more (I put some thin packing foam material).

That is what worked for me. Total cost for the improvement was some time + 49 cents for the wood - what is incomparable to usefulness of the modification and the fun I had doing that.

One more thing - for doorway mount I really like this type of chip-up bars and would not recommend any other "simplified" versions. Amazon has some available of the right kind - you can look though the search results:


Read more...

Free SketchUp 7.1 without 2D DWG and DXF Import - Ways Around

Recently the new SketchUp 7.1 was released. The most negative surprise from its free version is that import of 2D drawings in DWG and DXF standards has become impossible. Now this option is available in Pro version only.

It was a strange decision of Google to strip off the option: http://sketchup.google.com/support/bin/answer.py?hl=en&answer=161784, but anyway there are some ways to deal with it:

1. It seems Google feels that they have done something bad and to sweeten the pill a little bit they are offering optional temporary plug-ins: one for Windows and another for Mac... But it can not last forever and with the next version most likely the option will be gone completely.
   
   
2. One of possibilities is to keep an old working Sketchup version around. It can be kept on a hardware computer or on a virtual one. The former costs more as Hardware + MS license, but it should be fine if there is one extra Windows box around , the latter - is just for MS license (I don't know the deal with Mac). It's a pity there is no Sketchup for Linux, so the only option is to run it under Linux with WINE - some people say that it works.
   
   
3. Use another program to import DWG and DFX and then convert it into SketchUp file. I know one such program - Alibre. Alibre is a true dimension/parameter driven 3D mechanical development tool (SketchUp as we know is not) and there is a free Xpress version offered. The free version has some limitations as 5 unique parts in assembly, for example, but it still enough for a small project. I actually prefer to use Alibre for part and assembly development and then if needed I export design to SketchUp format. For the exporting there is a plug-in for Alibre called Alibre3DPublisherForGoogleSketchUp.exe. The bad news is that Alibre stopped providing the plug-in for download from its site officially and seems they do not want to support this option in the future, but it is still available from Alibre FTP libraries: http://www.alibre.com/alibrelibraries/ftp/addons/Alibre3DPublisherForGoogleSketchUp.exe; the good one is that the plug-in is still working fine with the new 12.0 version of Alibre.
   

Read more...