Right at the beginning

[DollyDiggerParticipant @dollydigger]

Posted by Nicholas Wheeler 1 on 03/10/2020 19:32:47:

That's why having made a start before you ask how to shave 1/2 a micron off titanium wire with only a granite kerbstone is so useful….

damm i just new i should have posted that one yesterday instead

[JasonBModerator @jasonb]

Few methods for the rails

For the rail either fabricate from 3 parts, top bottom and bent middle

If the height is right then cut down some box section to form the C section notch, bend and fill

Join two L shapes together with triangles cut out to allow them to be bent solder or weld together and add triangles to fill in the gap on the bends that opended up the joints. Although straight these channels were formed by cutting down angle iron and welding two pieces together

[DollyDiggerParticipant @dollydigger]

I have found some brass1/2×1/2×1/16 which is exactly the height needed, the top and bottom sections can be cut back to be the 8.5mm req.
Then side on i figure to mill the curved profile in or cut with bandsaw and file, then solder some flat section to match the 8mm top along the curve to the front.

Hoping this makes sense as it seems easy to understand in my mind.

With that said, this v8 will be 25cc and i imagine the cab to be none to light, should i consider as per jasons post?

[JasonBModerator @jasonb]

Sounds similar to how I would do it, Is the Angle that you have found? If so just imaging that the channel shown below is two pieces joined down the middle. You could also look into the 25mm sq steel tube used with knock in fittings to make shelves etc which if cut down would make a similar size channel.

I would make it up in one overlength piece and then mill off the top and bottom plus the dip at the front. Then bend the sideways jog. Once that is done silver solder on new tops and bottoms with the top also being bent to follow the reduced height. Keeping the vertical web as one piece will mean no butt joints so a stronger chassis rail.

As it is hard to line things up while soldering make the new top and bottom plates over width then you can file the excess off the flat outer edge first so it is flush with the vertical web. Then it is an easy job to mark or measure 8.5mm from that to get a uniform width for the return flanges.

[DollyDiggerParticipant @dollydigger]

Slight oops here, there is a 1 missing of my measurement in my last reply, it should read 1 1/2 x 1/2 which makes quite a difference

Thats some nice tube there jason, cheers

Here is a better idea of the spline guide which shows the curve profile from the top, as you can see the bend is not horendous, and the slope which is curved to over quite a distance.

[DollyDiggerParticipant @dollydigger]

I have seen a picture in an album by 'muzzer' from 06/08/2013, would it be possible to use this radius function on my dro in a back to back method to cut the 'S' curve looking from the top?

cheers

[JasonBModerator @jasonb]

If you have the ARC function then yes you can set it up for each of the two curves in turn. The other way to do it is to use CAD to give a set of Y co-ordinates for a regular movement of X which is what I often use.

[DollyDiggerParticipant @dollydigger]

Thanks Jason, so the first method i can look into tomorrow when i find the manual (its a new dro from machine dro) and see how to set it up for the arc, the second i have never come across, cheers

[JasonBModerator @jasonb]

This is the second method where I plotted the path of the ctr of a 6mm dia cutter as it moved along the blue shape at the top of the image at 0.5mm intervals so you just move one axis by the 0.5mm and then the other by the generated amount and make a cut, in your case a plunge cut would do.

This half round was done using a similar DRO and the flat ended cutter shown but it does take a while to get your head around how they work.

[DollyDiggerParticipant @dollydigger]

Well it makes good sense and i will have a look into fusion to see if i can do that, cheers

nice half round too

[DollyDiggerParticipant @dollydigger]

I found this as a surprise:

I thought 1 1/2" or 38mm mild steel channel would be a breeze to find, only to find that size is available in Ali, learning all the time

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