help making small hinges

[PeterT]

At least for the base part, I think you'd have to remove the bearing and cut the shaft off unless I'm misunderstanding.
They do sell corner rounding tools for mills but probably not in the delivery timeframe the OP has mentioned.
Good luck with the project. I repaired a so called brass antique hinge once, they can be fiddly buggers despite the innocent appearance.

 

[Megar arc 5040dd]

I will check what I have I might have a spare router bit I can modify if not I have HSS I can use. I will definitely let everyone know what I try and how it works out.

 

[Susquatch]

At least for the base part, I think you'd have to remove the bearing and cut the shaft off unless I'm misunderstanding.

I think it will work fine without that need Peter. Just run the bit axis parallel to the plate and at a right angle to the line between the screw holes. Box hinges only open half way so "the foot" of the hinge is flat for both halves.

I'm in the same camp as others here. Make the whole thing in one strip and then cut into pieces to form the two halves.

I dunno about drilling the hole that way though.

 

[Dan Dubeau]

I think it will work fine without that need Peter. Just run the bit axis parallel to the plate and at a right angle to the line between the screw holes. Box hinges only open half way so "the foot" of the hinge is flat for both halves.

I'm in the same camp as others here. Make the whole thing in one strip and then cut into pieces to form the two halves.

I dunno about drilling the hole that way though.

That's what the WEDM is for. Need a hole popper first though.......

I'd do that hole after parting to length, and cleaning up the ends to size, but before cutting the fingers. It's a deep LxD ratio, but not too bad. Setup a stop in the vice, and they'll all be perfect.

 

[Megar arc 5040dd]

Ok so small update and more question. I got a hold of a box I made my parents with the same hinges. Near as I can tell, using a magnifying glass to line up the caliper tips, the pin diameter is 3/32". I am in luck there as I own a set of accusize reamers from 1/16" - 1/2" and it had 3/32". My question is what size do I drill the hole to before I ream? And does anyone have any advice for drilling a hole that small 3/4" deep in brass? I also measured the thickness of the hinge leafs (I think that's what they are called) and they are only 3/32" thick. It that enough for the vise jaws to grip or will I need some sort of creative work holding when I mill it down to the L shape? I forgot just how small these hinges actually are. We are ordering a pair off of ali as a backup in case I fail. But I am bound and determined to succeed. With all the wisdom on this site how can I not.

Also dose anyone know generally how accurate the size is on 303 stainless round bar? It comes in 3/32" diameter but I don't know what the tolerance is on that.

 

[Susquatch]

My question is what size do I drill the hole to before I ream?

See, I'd like to learn from your question too. It is a good one. Here are a few more things to complicate matters for you.

You need the center section to turn freely and the outer section to hold the pin in place (or vice versa). I assume a pressed in pin. And I presume that means two different reamer sizes.

Reamers also come in under (-), standard, and oversize (+).

I'm looking forward to hearing the answer to your question!

And about drilling the hole, you should use a "sensitive drill chuck" for this job. If you don't know what that is, look it up. Maybe you can make a decent one. I doubt you have one. So you might have to be extra careful. The joy of machining!

 

[Megar arc 5040dd]

See, I'd like to learn from your question too. It is a good one. Here are a few more things to complicate matters for you.

You need the center section to turn freely and the outer section to hold the pin in place (or vice versa). I assume a pressed in pin. And I presume that means two different reamer sizes.

Reamers also come in under (-), standard, and oversize (+).

I'm looking forward to hearing the answer to your question!

And about drilling the hole, you should use a "sensitive drill chuck" for this job. If you don't know what that is, look it up. Maybe you can make a decent one. I doubt you have one. So you might have to be extra careful. The joy of machining!

The pin turns inside the center piece. Instead of a press fit and having to deal with 2 different sized holes I was just going to put a tiny bit of loctite as i slide in the last little bit of rod. The reamer I have is standard size that is why I was wondering about the tolerance of 303 stainless rod.

I don't have a sensitive drill chuck but I have a feeling that is the right tool for the job. I may have to add one to my list of tools to get.

 

[kstrauss]

The hinge uses countersunk flathead screws. How about drilling the holes and using screws to hold the hinge to a base plate while machining rather than using a vise?

 

[Megar arc 5040dd]

The hinge uses countersunk flathead screws. How about drilling the holes and using screws to hold the hinge to a base plate while machining rather than using a vise?

I thought of that but how do you hold it to machine it to thickness? If you put the screws in first you would machine off the heads bringing it down to thickness.

 

[kstrauss]

I thought of that but how do you hold it to machine it to thickness? If you put the screws in first you would machine off the heads bringing it down to thickness.

Drill the countersinks to the depth appropriate to the final hinge leaf thickness. That is, when you start milling to thickness the top of the screws will be well below the surface. When done you will be barely skimming the tops of the screws. Hopefully that makes sense...

 

[PeterT]

My question is what size do I drill the hole to before I ream? And does anyone have any advice for drilling a hole that small 3/4" deep in brass? I also measured the thickness of the hinge leafs (I think that's what they are called) and they are only 3/32" thick. It that enough for the vise jaws to grip or will I need some sort of creative work holding when I mill it down to the L shape? I forgot just how small these hinges actually are. We are ordering a pair off of ali as a backup in case I fail. But I am bound and determined to succeed. With all the wisdom on this site how can I not.

Also dose anyone know generally how accurate the size is on 303 stainless round bar? It comes in 3/32" diameter but I don't know what the tolerance is on that.

The pre-drill rule of thumb is 2-3% of finish (ream) diameter. Example 3/16 = 0.1875. 0.1875 * 0.98= 0.184"
0.98 corresponds to (1 - 2/100). 0.97 corresponds to (1- 3/100)
There are tables but a calculator works well for metric too LOL
Personally I ream with more like 5% without consequences, but its material & drill size dependent. Don't load the reamer with chips. Don't bottom out a reamer in a blind hole.
For example in brass or bronze, chances are you may be drilling with a dubbed tip in which case the hole can be a teeny bit larger anyway. Best to experiment on representative scrap

Pre-Ream Hole Size - Super Tool, Inc.

My preferred method for calculating the drill bit size is to take the desired finished hole diameter and multiply it by 0.98. Then take the desired finished

www.supertoolinc.com

Brass is pretty forgiving for depth but peck drill, don't let the chips pack in the flutes. Small diameter drills don't usually have to dub the end.

303 SS I've had is ~ +0.003" oversize, but it can vary.

 

[Dan Dubeau]

I'd probably drill about 0.005" under on that before ream. I wouldn't worry about over under reamers here. There's a time and place for that, but for a one off job, just take your pin in a drill chuck and with a narrow strip of emery cloth just polish the center section out where it will ride in the center section a bit. That'll give you enough clearance to hinge freely, while leaving the ends a nice fit in the fixed side. You can test it as you go to get the fit you want. Either use loctite, or my preference for this would be to slightly peen the ends over to set the pin in place, then file flat.

As to over under reamers, they are certainly the right tool for the job when you "need" to hit a size on a print, or for something very critical. But for shop projects, and a lot of other situations like this (non/semi critical), where it's a one off, learning to make things bigger/smaller with peening, or polishing is a handy skill to have. A ball bearing about 2x hole size given a small tap on a hole will create a nice press fit too. Handy thing to have in your pocket when you only have an onsize reamer, and need to create a doweled joint and want the dowel to remain fixed in one half (slip/press). Little chamfer on the hole, give it a tap on the ball, and it'll tighten that hole up enough to retain the dowel, and have no effect on your position at all. I have a nice "ball punch" made from a chunk of 1/2" aluminum hex, with a tooling ball press in the end. It got used (and borrowed) a lot. I had a smaller one where I brazed a small 3/16" bearing into the end of a steel rod, and used that a LOT for 1/8" sized dowels until it grew legs a few years ago. Always wanted to make an entire set to cover all the bases, but it's not that size critical, and I never really got around to doing it......Maybe someday....

 

[Megar arc 5040dd]

Drill the countersinks to the depth appropriate to the final hinge leaf thickness. That is, when you start milling to thickness the top of the screws will be well below the surface. When done you will be barely skimming the tops of the screws. Hopefully that makes sense...

That makes total sense. I Don't know why that never occurred to me. Thank you!

 

[Susquatch]

@Megar arc 5040dd

I saw this and thought of you. Not sure what radius you need, but at this price, it seems pretty attractive. Saves trying to grind your own. Note that other radius tools are available at this link.

https://a.co/d/eQTGIGk

 

[Megar arc 5040dd]

@Megar arc 5040dd

I saw this and thought of you. Not sure what radius you need, but at this price, it seems pretty attractive. Saves trying to grind your own. Note that other radius tools are available at this link.

https://a.co/d/eQTGIGk

Thanks! There isn't quite the size I need but I would bet it's close enough to work. I am going to quickly play with the 1/16" radius and 1/8" radius in autocad and see what get me the closest. I can have it here for tomorrow so that works out great. Your timing couldn't be more perfect. I started on making a fixture last night to screw the pieces to for machining.

 

[PeterT]

I have used similar HSS versions on aluminum & they work well. Don't get too aggressive on thinly held parts & it should go fine for brass. Similar to what I showed in post#21 other than those are carbide via AliExpress. They are very accurate, reasonably priced but predominantly (if not entirely) metric radius. But sounds like you have time constraints anyway. I can't speak for Accusize specifically on these particular cutters, but my experience is been good to deal with directly or through Amazon if a dud, which does happen on occasion. Good luck.

 

[Megar arc 5040dd]

Ordered up a 1/16" radius it will be here tomorrow. I needed a size right in between 1/16" and 1/8". I could probably have gotten away with either so I went with the one that can be here tomorrow. Now if it actually shows up tomorrow I will be impressed but I'm not going to hold my breath.

 

[Megar arc 5040dd]

Bit of an update. The prototype/proof of concept is done. I had two small pieces of 1/4"x3/4" brass in the scrap drawer. So I decided to try with that before buying material just in case I bit off way more than I can chew. once the pieces were to size I made a fixture to hold them while I milled the step into them and milled the radius on. The fixture worked perfectly.

 

[Megar arc 5040dd]

Then it was time to drill and ream the holes for the hinge pins and that is where I ran into problem number 1. My parallels are .125" thick but the leaf of the hinge is only .0885". Plus I needed access to the hinge to verify it was held square. This is what I came up with and for a one off it worked fine but after I was done I had an idea for another fixture similar to the first one. I will make that for repeatability on the next ones.

I checked both for square with a test indicator on both the x and y plane. In the y direction I was out .0015" when indicated from top of piece to bottom. I wasn't super pleased with that but it worked. That was part of the reason I designed a fixture for the next one.

 

[Megar arc 5040dd]

The last step was to mill out the ends of one piece and the center of the other. I didn't end up taking any pictures of that but I solved my parallel problem by using an off cut of brass to go between the movable jaw and the hinge leaf. I took .010" depths of cuts just to be safe. I couldn't get stainless locally in 3/32" diameter but I was able to get 3 feet of drill rod so that is what I used for the pin. It fit perfectly in the reamed holes. The only issue I had was when cutting it in the bandsaw it bent about 1/2" that was sticking out of the vise to the blade right when it finished the cut. I will make up some sort of quick jig for cutting the rest of the pins.

The finished piece turned out better than expected. I worked it out and material cost to make them is just under $2 per hinge.
Dime for scale since I couldn't find a penny.