Was making up a prototype of something last week, which used a very common method of joining a bolt mounting point to a tube structure. This is just a random pic I grabbed for visual reference, but basically the same thing as each of the mounting points in this brace:



Just because I was making something on the spot and didn't even have washers of a thickness/diameter I wanted for this, I made those "cups" for lack of a better word from scratch - cut a short section of DOM, then cut out a disc from plate steel equal to the OD of the tube, drill out the center to the bolt diameter, chamfer the outer dia. for space for the weld to fill, then weld this cap to the tube end.

In short, way more work than ought to be necessary, and I'm sure these have to be available pre-made somewhere, but I haven't come up with anything googling all the terms I can think of that they may be called. Any suggestions?

-Ryan

 

I would look at the off-road community. Maybe call Rusty's Off Road and I'll bet they could at least point you in the right direction if they don't make them already.

 

I'm not sure, but if you make some I'll probably buy it.

 

Yeah most of the results that have popped up while googling have been off-road sources. I'll call Rusty's tomorrow..

My last wavering whisp of faith in humanity would fade away if there isn't a fabricator out there yet who made the same thing from scratch and decided these needed to be mass produced.

-Ryan

 

essentially what your looking for is a thicker wall and taller sleeve cup washer? A quick McMaster search yielded me this which wouldn't work for the application you have pictured as they are much too small, but at least you have nomenclature to work with.

Its under sleeve washers.. it wont let me shortcut the direct page for some reason
McMaster-Carr

 

Maybe a pipe cap could work for that application.



Manufacturer of ASME B 16.11 Pipe Cap|Leading exporter of ASME B 16.11 Pipe Cap |ASME B 16.11 Pipe Cap Dimensions | ASME B 16.11 Pipe Cap at best price - Redearth Steels

 

That pipe cap looks great, although I didn't see what it is made of. I have always made mine like you did in your pic. It seams like, turn one on a lathe or cap a tube, they are all an extraordinary amount of work, for such a small part.

 

Even just using a washer for the cap would save a good amount of time over making the cap portion from scratch, but then I'm concerned about the integrity of the washer - all of the load on that bolt depends on that area.. whereas if I cut and drill the cap out of cold rolled steel I know exactly what I'm using. And a ~0.125" thick washer in untreated/non-coated mild steel with a large OD like 1.5" is a bit of a specialty item as well.

It's the silliest little things that can be the most trouble..

-Ryan

 

Send Jim Pierce @ Pierce Motorsports an email, tell him that nutjob with the KL Escort that bought his entire catalog sent you. He uses a ton of these in his tubular subframes and bracing. He may very well make them himself, but if not, he's a nice dude and will probably share his source.

He's located in City of Industry if you want to make a day trip or something.


"Ultra Racing" uses these in all their braces as well. I believe they weld the cap up, though. At least they did on the 4pt front brace i have on the MX6.

 

I resorted to the washer method last time. I doubled up two grade 8 washers, then welded. Not great practice, but never failed either.

It does seam like a great cnc job with mild steel.

 

Maybe this is just me, but I don't like the idea of using washers.
Why not a simple piece of round stock cut real thin? Find center, drill hole, weld on.

 

Well I guess I forgot to add that I used the heavy washers. But your probably right, drill a hole in round stock, then part them off at the desired thickness.

 

Agreed, washers are the DIY homebrew way to do it, round stock is the appropriate solution for professional fab.

Called Rusty's off-road and emailed them pics, those pics apparently circulated around their whole shop and although everyone knew exactly what I was talking about and has seen them in many different applications, they had no idea what to call them or if they are available pre-made anywhere.

Figures haha.

They offered to put together a quote for making me some if I wanted to send them the specs I wanted but really each project is going to need different specs, bolts hole diameters, etc. so at the end of the day I think it just makes sense to get some round stock in the couple different diameters that I may want to make the cups from, have a shop cut me a bunch of discs in X thickness, and stock those. Then drill out to the diameter I need for the project in front of me and weld to the tube.

-Ryan

 

Is beatrush around at all? They use that sorta thing in their ppf/diff brace, I wonder if they'll respond with a "name" of that part. But I think you answered your own question. With the small number of applications, and wide veriety of hardware/pipe sizes, they're probably all made per project.

 

Beatrush uses some sort of poly/delrin insert with a steel sleeve in their PPF brace. Think of the aftermarket differential bushings for our cars, but on a smaller scale.

 

Maybe a bit faster way to make these, but I have a hole saw set where I can put different sized drill bits in. Get the bit sized to the hole you need in the middle and crank the "washers" out on the drill press with some of those nice carbide tipped hole saws.