binding barrel bolt meets a carriage bolt

[magicniner]

You need to step away from your fixation on a fastener designed for easy use in non-engineering applications, they don't make threaded Chicago Screws without driver slots because they need to be user friendly for their intended purpose, holding together books, material sample swatches etc.
Use a length of tube with two press-in ends.

[JEK5019]

indeed.

my primary concern is movement. is there an epoxy that i can use where the tube meets the channel?

[magicniner]

indeed.

my primary concern is movement. is there an epoxy that i can use where the tube meets the channel?

To do what? You don't have the area to securely bond the tube to the channel with epoxy so why would you want to put epoxy there?
Tube
Holes in the channel the same size as the tube ID.
Hammer Drive Screws
Job done.

[JEK5019]

okay -

so this seems like a viable solution. however, i would imagine that after pressing in the drive screws - they would probably 'slighting' bulge the inner tube - thus creating friction for the center barrel to rotate smoothly?

is this correct?

[JEK5019]

i should also add that these pieces are quite small - that center hole is 0.4 cm. i would need a ID tube of 0.4 cm with a reasonable wall thickness to prevent bulging?

is something that small even available?

[cropwell]

It would help if you could give us an idea of what you are trying to achieve. I respect that you may not want to disclose the end use, but some indication of the forces involved may be useful. Also is the axle to be free to rotate in the yoke or must it be definitely fixed? Are you looking to scale up to produce many units, or are you making just one or two? What material is the roller? Will it be wet (aqueous), oily or dry in end use? Do you have a unit cost limit in mind?

If you wanted a quick bodge you could pop rivet a length of tube into the yoke.

BTW cm is not a preferred unit in engineering, metric users prefer mm. In the US they use inches a lot (but not excusively). Some of the Model Engineers in UK use imperial measure, while some of the absolute recidivists use Furlongs, Newtons per square fortnight, Firkins and Ducats per gross. Oh! and BA screws.

[JEK5019]

thanks cropwell.

so i looked up the wallpaper seam roller you had mentioned - and the design i am working will work just like that, in fact! but unlike many of the designs, i came across - where the roller bracket is on one side only - my design will be built like an axle.

attached are several of these wallpaper seam rollers that more or less fit my goal and operation.

in my design goal - i am wanting to avoid any welding/sanding finished. i would prefer fasteners - but with no drives. very clean!

[JEK5019]

so the handle will be metal/wood lather operation.

the channel/bracket and the roller - all metal. no plastics.

the approximate pressure and use will be similar to that of the wallpapaer seam roller.

and lastly - if i can resolve this issue in the design and move forward - the goal will several hundred units at first. if i can market it well and proves successful - then definitely a few thousand thereafter.

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also - i am living in iceland and it'll be costly to manufacture here. i am beginning to source out manufacturers throughout europe and states. i need to start some cost estimates

do you have recommendations for any machine shops to contact?

[magicniner]

okay -

so this seems like a viable solution. however, i would imagine that after pressing in the drive screws - they would probably 'slighting' bulge the inner tube - thus creating friction for the center barrel to rotate smoothly?

is this correct?

No, it's not.
Drive screws have a fast outer helix with a relatively high sharp profile, they are designed specifically for blind holes where the relative sizes can be chosen such that material distortion stays local to the hole walls, among other things they are commonly used to fix data plates to castings.
You could make the holes in the bracket a tighter fit to give a lot of hold and the hole in the tube the right size to prevent rotation and give adequate retention without distortion of the outer.
It's your job to experiment with drive screw size, tube hole size and wall thickness to get the materials behaviour you require for your application.

[JEK5019]

thanks magicniner. i guess it is a matter of experiment - much appreciated.

i'm currently using mcmaster as a source for stock items (as it allows me to drop in the actual 3d product into fusion 360 - enabling the design) however, their tube selection seems rather marginal.

do you have recommendations for manufacturers for smaller sized metal tubes?