Drafting a part by taking a picture of it

[Fastyankee]

I more than oftan have to draft a prt to fit an existing part. This can take a lot of time with to do some times.
I'm in the process of building an over head crane in my shop to handle the steel and car frames I build. I want to make simple saddle to fit the frofile of the I beam mainly the bottom flange so it slips on the end and I can than weld it on the beam. I thought maybe I could take a picture of the end of the beam and trace it. Or go the tape measure and angle finder out and do the old school drafting. I have traced parts out on paper and scanned it in and traced it with some success. Your thoughts?

[Joe Jones]

Beam trolleys are already available. What do you need that is different from what is already designed?

Joe

https://www.northerntool.com/search?s=i-beam+trolley

[Dirtmotor]

I would think you could do it , It might be ard to get the scale right , can you trace actual beam flange ?

[adbuch]

I more than oftan have to draft a prt to fit an existing part. This can take a lot of time with to do some times.
I'm in the process of building an over head crane in my shop to handle the steel and car frames I build. I want to make simple saddle to fit the frofile of the I beam mainly the bottom flange so it slips on the end and I can than weld it on the beam. I thought maybe I could take a picture of the end of the beam and trace it. Or go the tape measure and angle finder out and do the old school drafting. I have traced parts out on paper and scanned it in and traced it with some success. Your thoughts?

AJ - you should be able to take a picture looking straight on from about 3 feet away and use that for either an auto trace or manual trace scaled to the correct size. For testing your file you might consider using a sharpie pen holder attached to your torch and draw it onto a piece of paper or cardboard. Then you can cut out your drawn template to see how closely it matches to your actual beam and make adjustments accordingly.

David

[adbuch]

I would think you could do it , It might be ard to get the scale right , can you trace actual beam flange ?

This is a good idea as well. Just put a piece of cardboard up to the end of the beam and trace around the beam with a pencil or sharpie. Then cut out your template (and optionally paint it black) and take a photo for auto trace. I have done the same and it works well.

Below are several examples I have documented to help show you how I have done it in the past.

David

https://photos.app.goo.gl/CnePLkzmKUyesqXy8

https://photos.app.goo.gl/HyrwMz8KQd9fdAdg8

[adbuch]

I more than oftan have to draft a prt to fit an existing part. This can take a lot of time with to do some times.
I'm in the process of building an over head crane in my shop to handle the steel and car frames I build. I want to make simple saddle to fit the frofile of the I beam mainly the bottom flange so it slips on the end and I can than weld it on the beam. I thought maybe I could take a picture of the end of the beam and trace it. Or go the tape measure and angle finder out and do the old school drafting. I have traced parts out on paper and scanned it in and traced it with some success. Your thoughts?

I have done it the "old school" way in the past as well using tape measure, angle finder, etc.

David

[ROKCRLER]

Have you checked mcmaster for the dxf?
https://www.mcmaster.com/products/i-beams/

[tcaudle]

There are some things to be aware of if you go the photo way. First the lens and focal length should be normal and not distort the imge. Working too close and some lenses Wil take the picture but you get distortion . Better to take the photo far away ans either use a zoom lens or enlarge it in photo software.

The higher the contrast the easier it is to trace. I have been known to spray the object black and place it against white background. Where it gets fun is on 3D stuff, or assemblies .

If you can do a three view drawing of something (top/front / side usually you can break it down into flat parts or you can do a 3D drawing (or at least an isometric view.

the "plane "of the came (where the image falls inside) and the plane of the object have be exactly 90 degrees (perpendicular) in both directions. That may not be as simple as it sounds .Even a few degs off and you will have a skewed shoe. Once again the further you are away the less it matters .

Sometimes a mix of old school and the photo method work best. Hand draw a sketch and take measurements . use the photo to hand trace and try to work in closed objects . use you hand drawing and notes to "adjust t; the final drawing paying closer attention to areas that have to be accurate of fit other parts.

If I build stuff out of conventional square tube, sheets and angle, I make those parts up to size and change the lenghts

and then do a 3 view drawing. That usually is enough to precut the pieces and weld them up into the correct shape.

[Fastyankee]

I like the cardboard cad idea were I can spray it black and take a picture of it. Once the shape is scanned in scaling it usually not a big issue. I have to mount two beam trolleys together so the beam can’t cock when rolling it along the bridge beams. I have also traced parts on to paper and than scanned it inn the computer and that has worked well. Time is money so anything to save time is money saved.

Thanks for the input

[djreiswig]

Should be able to find all of the dimensions for your beam online and simply draw it out. That would be the most accurate in my opinion.

[adbuch]

I like the cardboard cad idea were I can spray it black and take a picture of it. Once the shape is scanned in scaling it usually not a big issue. I have to mount two beam trolleys together so the beam can’t cock when rolling it along the bridge beams. I have also traced parts on to paper and than scanned it inn the computer and that has worked well. Time is money so anything to save time is money saved.

Thanks for the input

AJ - I think you are on the right track with your cardboard template, particularly if you can trace it directly off of the end of the beam. Then cut and paint black as you say, etc. Let us know how you make out, and perhaps take some photos to document your process.
Thanks,
David

[Joe Jones]

I have to mount two beam trolleys together so the beam can’t cock when rolling it along the bridge beams.

I am trying to picture this condition that you are worried about. What can "cock" by rolling it along a bottom flange of an I-Beam?

I am left-handed, so I naturally think in pictures. A couple of photos or drawings would help immensely.

Joe

[Fastyankee]

If you try to roll a beam along two parallel beams on a single fulcrum point it has the tendency to pivot and get cocked if you use two beam Dollie’s you make the fulcrum point wider so it doesn’t want to pivot .

[Joe Jones]

If you try to roll a beam along two parallel beams on a single fulcrum point it has the tendency to pivot and get cocked if you use two beam Dollie’s you make the fulcrum point wider so it doesn’t want to pivot .

Ah! I understand your concerns now.

Joe

[Joe Jones]

I am reminded of how PlasmaCam keeps their gantry in line. They have a drive shaft that spans the two rails, and a gear rack in each rail. The driveshaft prevents one end of the gantry tube from advancing faster than the other end.

Joe

[kicktillmonday]

I am reminded of how PlasmaCam keeps their gantry in line. They have a drive shaft that spans the two rails, and a gear rack in each rail. The driveshaft prevents one end of the gantry tube from advancing faster than the other end.

Joe

But there are rack and pinion gears on both sides that aid in keeping both sides true, in this case that would not be an option. I would likley do some follower bearings spaced a decent distance apart from the center of the bean trolley to help prevent either side from getting ahead of the other.

[SegoMan DeSigns]

If you try to roll a beam along two parallel beams on a single fulcrum point it has the tendency to pivot and get cocked if you use two beam Dollie’s you make the fulcrum point wider so it doesn’t want to pivot .

The gussets and additional length needed for them can be eliminated with a double girder crane that will increase your lifting capacities. Have you considered that design?