binding barrel bolt meets a carriage bolt

[JEK5019]

i'm sure it is - however, this is a small smart in an overall design i am working on - if the design proves to be successful - i'll be needing to make approximately several thousand pieces easily!

custom work at that level wouldn't prove cost effective - so i am trying to manage ready-made assets, if possible.

[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.

[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?

[hanermo2]

A peen, aka pin punch on one corner of the flat blue bolt flat area will mostly lock it in place.
This can be done in an inside-supporting fixture, think fork, avoiding distorting the U shaped hold.

Any industrial epoxy will fix the blue bolt, depending on load and the size of the end plate surface area.

A fast small drill through the holding bolt edge (blue), and a pin, punched, would also work.
So would e.g. blind pop rivets.

Press-fit barrels would definitely work.
Both for holding them, and the ends pressed in.
They need precise holes for press-fit purposes.
Think reamed to 0.01 mm in D, more or less.

Typical std reamer accuracy (0.01 mm in smallish D), easy to do, cheap, fast.

Custom barrels are probably much cheaper than anything like that from mcmaster in qty 3000 units.

Typically, mcmaster/misumi/etc cost 1-2-3$ for engineered units of any precision.
Industrial epoxy will likely cost 1$/unit, +/-, in small quantities.
Total 4$, or so, qty 3k total.
Plus lots of work in assy, several $ each. You cannot assemble 60 per hour.

You could get 3000 units of barrels and fitments and an assy jig (pop/rivet/pin) made by any jobshop for around 10k$.
And maybe a drill-jig to make the forks yourself.