Hinged joint preferences

[Xyphota]

I'm designing a tube clamping block with a hinge. What would your preference on a hinge be? I was planning on buying a hinge and bolting it onto the side of the block, but I think the fit and finish might not be to my liking. I could potentially machine a pin receptacle into the blocks. The axis along the hinge is only 1.5" wide for and the block is going to be made of aluminum if it matters.

 

[PeterT]

Assuming it has to swing completely open to load something from the front? I've seen nice quality hinges when they have to support something heavy like steel doors. And also from distant memory some of the Gucci euro cabinet hardware stores for 'bolt-on' possibilities.

If it just needs to open up to accommodate side loading, you could use dowels & the parts would likely repeat position better. Maybe arrange it so it so you can use a quick handle or something vs top latch? What gets held in the bushing?

 

[PeterT]

Generically what I see in office buildings etc.

 

[Xyphota]

Doesnt have to open completely, 90 degrees should be sufficient. Dowels might be a better approach so I'll look into that, but I think a hinge would be less faffing about in practice.

The orange bushing looking pieces will be swappable for different internal diameters so that various diameter tubing can be held in place for mitering in the mill.

 

[Dabbler]

Your hinge choice is dependent on expected loads. If it is a milling load, have a look at your lathe steady rest. Those hinges are designed for higher loads. For lighter loads a 1/4" dowel pin may suffice. (even then a 1/4" dowel will resist some good loads.)

Princess Auto has a nice weldable 2 pc hinge that might work very well...

 

[Susquatch]

What would your preference on a hinge be?

Assemblies like that are only as strong as their weakest link. In this case, you have a closing clamp and a hinge that are miniscule compared to the block. In the surface of it, that seems to be a bit of a contradiction.

If I were you, I'd start by asking myself if I really needed a clamp block that big.

If so, then I'd abandon an external hinge and lock and I'd machine them both right into the block with hinge fingers and lock pin diameters in the range of 1/3 the cross sectional area. Think mitred halves with a hinge pin. If I understand your application, I don't think the fit is all that critical so it's an easy milling operation to make the mitres and any play could be taken up with thin plastic washers to align the halves. Drill for the pins after the hinge mitres are finished so everything lines up perfectly.

If not, I'd abandon the entire block and modify a typical door hinge to serve as both the hinge and the block. Door hinges are available in a very wide range of sizes and types. Most are easily bent and many can be modified (machined, cut, welded, etc) to serve as both ends of your clamp.

If you want a quicker solution, you can also make or buy huge hinges for barn doors, safe doors, cold room doors, etc that could be cut down to fit your block with a strength similar to the block.

Or, here are some quick buy heavy duty hinges that are prolly more like you had in mind.

Atibin 3 Screw Heavy Duty Stainless Marine Door Hinges https://a.co/d/d1zlKKA

Atibin 2 Screw Heavy Duty Stainless Marine Door Hinges https://a.co/d/20CA3Ca

A Google search for Heavy Duty Hinges turns up a million other options. In your case, I think a pair of thick steel hinges might be all you need.

But as @Dabbler said, it all depends on the loads you expect to encounter.

 

[PeterT]

The orange bushing looking pieces will be swappable for different internal diameters so that various diameter tubing can be held in place for mitering in the mill.

I see. Well as a general holding/fixturing principle, a round within a round can have drawbacks too depending material OD variations and/or the fixture itself. If the tube is just a little undersize or oversize or eccentric, the resultant fit can vary between too loose, point tangency or not at all (upper sketch, exaggerated). A vee is more universal purely from that standpoint, but it only offers max 4 tangent contact points when clamped from both sides & the centers will be different if that's an issue. But if you are working with more fragile thin wall tube, vee might not be the way to go either.

Back to round - sometimes when you see plastic or hard rubber inserts, its more about adapting to OD variations, not marring or stressing the surface, that kind of thing. I think we just invented the need for a scroll chuck 300 years after the fact LOL. Now if your tube OD happened to match an ER-40 collet range, you could get a cheapo ER fixture block / chuck plate & be home free, but I'm guessing these tubes might be bigger diameters & maybe you need to index the tube at different angles?

 

[YotaBota]

How much play can you afford between the hinge pin/body and is there a plan to account for this play? Most commercial hinges have more play than "machining/machinists" can tolerate.

What size holes are we talking about?

 

[Janger]

Is that a rotary table behind your mechanism? Chucks are sometimes mounted to RT's to hold round parts. and you seem to have a sliding plate there. What is this for? Interesting. and lots of detail in the CAD model.

 

[Janger]

https://canadianhobbymetalworkers.com/threads/3-jaw-chuck-backing-plate-for-rotary-table.1203/

Rotary table with Chuck project.

 

[Xyphota]

The hinge in the model is the first one I pulled off Mcmaster, so I know it looks a bit anemic haha. Those Atibin hinges @Susquatch pulled off amazon might actually work pretty good. Most of the stout hinges with given load ranges are physically bigger than what I am looking for.

As for clamping the tubes with round dies vs v-blocks, I want to keep the tube axis passing through the same place on all sizes, so the round swappable dies are more work but preferred in this case. V-blocks are used in some tools like this like the one shown in the image below.

@Janger I am making a mitering fixture for tubing that would be welded into a roll-cage for example. The rotary table is rotating a tube in a different axis then you are thinking. Here is a similar tool that would otherwise cost USD$1500.

 

[Janger]

Interesting approach- how is this better than one of those drill press tube notch accessories? Is that a lathe holding the hole saw?
Eg

JD Squared The Beast Notcher

The Beast is the ultimate in hole saw tube notching. Able to easily handle straight notches, offset notches, angled notches, and notches in bendsCapacity of 3/4" to 3" ODStraight, Angle, and Offset Notching Offset notch up to half the tube diameter.Angles

www.kmstools.com

 

[Xyphota]

I think the picture above is a horizontal mill, mine will be mounted in a vertical mill. Functionally similar to those tube notchers, but those can be a bit of a pain to setup the angles and offsets. Those tube notchers also don't support the tube very well up where the mitering happens, so it can be challenging to miter thin wall tubing with those. Most of the tubing I'll be working with will be ~0.035" wall thickness.

The fixture I am building has a dummy tube on the opposite side of the tube being cut so you can pretty easily miter the tubes at the correct angles and length.

 

[Six O Two]

How much notching are you going to be doing exactly? I'm wondering just how much time you'll be saving operationally with a quick release clamp and hinge setup vs screws, while also considering the slop that might be inherent in a hinge. Most of the bike frame building tube notchers I've seen (other than the Anvil fixture you show) use screws or at least a thumb screw and pins to securely clamp the tube. It's a lot easier to drill and tap holes than installing a clamp and hinge though, so that might have something to do with it.

I like Sputnik tool's solution with a thumbwheel and pins (also, v-block for multiple size tubes).

 

[Former Member]

Pipe/Tubing Notcher

Amazing deals on this Pipe/Tubing Notcher at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

 

[Susquatch]

Pipe/Tubing Notcher

Amazing deals on this Pipe/Tubing Notcher at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

Looked at your Harbour Freight link and suddenly I have a much better idea of what the OP is trying to do!

Ya, I'd be making my own fixture too.

Annular cutters on a mill would turn that job into a piece of cake once you make the right fixture.

 

[Former Member]

I've seen the HF unit in person and for the money unless you already have materials and the time, can't beat the price.

Is it as good as the OP's concept likely not as tight tolerances but for weld fitment close enogh.

 

[Janger]

I
And in canada

Magnum 1/2"-2" Tubing Notcher

Use this precision piece of equipment to cut round holes at various angles in pipes and tubes.

www.kmstools.com

 

[Former Member]

I
And in canada

Magnum 1/2"-2" Tubing Notcher

Use this precision piece of equipment to cut round holes at various angles in pipes and tubes.

www.kmstools.com

Painful in pricing. US$58.00 = CDN$80.00 vs CDN $160.00 from KMS.

or

VEVOR Tube Notcher Kit 60 Degree Pipe Tubing Notcher w/18 Pc Bi-Metal Hole Saw 3/4" -3-1/4" with Case Tubing and Pipe Notcher 4 Drills Tube Notcher Tool for cutting holes through Metal, Wood, Plastic., Tube Cutters - Amazon Canada

VEVOR Tube Notcher Kit 60 Degree Pipe Tubing Notcher w/18 Pc Bi-Metal Hole Saw 3/4" -3-1/4" with Case Tubing and Pipe Notcher 4 Drills Tube Notcher Tool for cutting holes through Metal, Wood, Plastic. in Tube Cutters.

www.amazon.ca

and some suppliers wonder why we shop elsewhere.......

 

[Darren]

I've seen the HF unit in person and for the money unless you already have materials and the time, can't beat the price.

Is it as good as the OP's concept likely not as tight tolerances but for weld fitment close enogh.

I was just at a Harbor Freight store on the weekend. I should have bought one. Can't beat that price.