Chainstay to Dropout Options

[Clockwork]

I've been slotting the chainstay at an angle to receive the dropout for silver or brass brazing. I'm starting to think about other ways of doing this since it takes me a while and is a common place for me to make a mistake. I start by marking my cut with a Sharpie and make my first cut with a hack saw and make adjustments with a file. I also am not fond of the sharp corners at the end of the slot. They look like a great place for a crack to start.
Attachment 17028

Are there any problems with case 1 or 2? Especially in the case of Paragon sliders?
Attachment 17027
Attachment 17029


Thanks for the help,

Joel

[e-RICHIE]

i opt for the first option atmo -

[conorb]

We slot the chainstay as you have it in the traditional picture. We also notch the dropout like you have shown in case 1.

Then we'll generally back cut the stay before brazing. We find this gives us a variety of finishing options from points to square to flush in.



Conor

[e.Gellie]

....slotting the chainstay at an angle to receive the dropout for silver or brass brazing. .........I also am not fond of the sharp corners at the end of the slot. They look like a great place for a crack to start.

Are there any problems with case 1 or 2? Especially in the case of Paragon sliders?

Joel,
your 'Traditional' is the most robust of your 3, with the greatest brazed surface area. But it's not like what I call traditional since it doesn't have the dropout stepped down so it fits inside the stay for the extra surface area as in my pic; that is the benchmark that has been proven. Moving away from what's proven can easily make it less robust in my mind. I reckon your Case 1 actually has more area than your Traditional! Your Case 2 tabs wouldn't add much strength because their section is so thin.

I make straight slots and bend the dropout tabs to suit. I made tools to speed both of those steps; no photos handy sorry.
For stainless I look to add more surface area as in the pic.. For Paragon sliders which add more load to stays than than the Traditional arrangements, I'm really looking for that extra area, especially with silvered joints;

I've newer-ever seen a crack start in the square when it was done the Traditional way, brass-brazed....that square corner isn't flexed open-and-shut, it's filled from inside with a plug of brass.

pic. joint for silvering; pre-slotted brass-brazed plug, chisel end added with Multitool belt linisher with a guide. Stainless fork-end.

[Rody]

Joel,

If the issue is accurate repeatability in an efficient manner, would a change in process be the ticket?

I slot all my stays on a vertical mill; the stay is slid into a vice with an established stop for position, the angle is set by tilting the mill head, and the slot width is achieved using a stacked slitting saw with a custom spacer.

The whole shebang is done in less than 10 minutes (with a couple sips of hot chocolate intermittently).

All right, the pics are in reverse order, so I totally suck, but you get the idea

rody

[Zimmermanbicycle]

I use more or less the same process as RODY,doesn't take so long and gives you a few choices on finishing,goes pretty quick with a hacksaw too,may even be faster than the mill.
-Eric

[Tom Kellogg]

We do pretty much the same, except that we use an old 11.5" Southbend lathe. Our slotting saw is much thicker than Rody's so that Jeff will do one pass, turn the compound in X thou. and do another pass to suit the thickness of the dropout to be used. Instead of bending the dropout, Jeff has found that is easier to cut the slot at the angle that is needed for the frame. I will do up a quick AutoCAD elevation to get within about fifteen min., then he will tack the dropout in the jig to get the "H" perfect so that we don't need to set it later. Unless we are using an SS dropout, we always use LF bronze. For SS, we use nickel-bronze. When it comes to Paragon SS slider dropouts, you pretty much have to slot on the angle since the stay will bend before the dropout if you need to set the dropout "H." Helps?

[marten]

We do pretty much the same, except that we use an old 11.5" Southbend lathe. Our slotting saw is much thicker than Rody's so that Jeff will do one pass, turn the compound in X thou. and do another pass to suit the thickness of the dropout to be used.

I use a 2mm wide slotting saw, adjust with the slide against the stop, and make the second cut with a piece of suitable thickness (~3mm) between stop and slide

[steve garro]

i slot them at an angle with a boring old sharpie, hacksaw & warding file. i'm pretty damn quick & accurate. millions of bikes were made with slotted dropouts & i never saw a slot fail - just busted driveside dropouts. cut apart some old bikes - there's barely a lipstick smudge around the edge of the slot of brass on most. Shit....... millions of bikes just have the mild steel stays smashed onto the seemingly improbably thin drops & they hold up for years - Garro.

[suspectdevice]

Another great option (and possibly the cheapest and most space conscious) is to use a small horizontal mill with Tom or Rody's method. If you only do slotted stays it makes a ton of sense to have a dedicated fixture and machine for it. With some locating pins you can easily swap the machine over to chainstay mitering too. That might only be time effective for serial production though...

[Dazza]

why the reluctance to do the slots straight along the CS
and then bend the dropout to the correct required angle after brazing?
checking in the fixture to get it all correct and adjusting.
Then when doing the seat stays one bends the top of the tip to what is required.
Vice and smooth jaws and push
I always thought this was the way to do it.
For roadies and trackies any how.

PS. If I had the room and if I had the constant need I would set up an old mill for slotting.

[Tom Kellogg]

why the reluctance ...

For us, it just kind of developed. When I were only using hot forged dropouts, I always slotted in line with the stay since the dropout yield strength was well under any of the stays we were using. Once we started having Paragon make our track dropouts out of 4130, we had to start slotting on the angle since the dropouts are WAY stronger than any stays that we use. Once we had gotten a system going, we found that it saved time, both in fitting up the frames and in cleaning. So now we just keep doing it that way. Does it make a better bike? Heck no! But for us, it is necessary on some frames and is easier on all frames. Helps?

[conorb]

why the reluctance to do the slots straight along the CS
and then bend the dropout to the correct required angle after brazing?
checking in the fixture to get it all correct and adjusting.
Then when doing the seat stays one bends the top of the tip to what is required.
Vice and smooth jaws and push
I always thought this was the way to do it.
For roadies and trackies any how.

PS. If I had the room and if I had the constant need I would set up an old mill for slotting.

We cut the slots straight (4" angle grinder, thin blade, file cleanup) as well and then bend the tabs for the seatstay attachment as well the drop for proper angle with the rear triangle.

I don't see the other method as reluctance just another method.

Conor

[Dazza]

We cut the slots straight (4" angle grinder, thin blade, file cleanup) as well and then bend the tabs for the seatstay attachment as well the drop for proper angle with the rear triangle.

I don't see the other method as reluctance just another method.

Conor

Agreed
but as I work this morning on the XCr luggie
me thinks
I cannot file desirable pointy tapered bitsie bits along the drop to tube fitting if the drop out is angled into the tube

For other finish styles would be fine

[e-RICHIE]

Agreed

I cannot file desirable pointy tapered bitsie bits along the drop to tube fitting if the drop out is angled into the tube

it's a high style, hand-eye, muscle memory task and that's why they pay us the big bucks atmo.

[Dazza]

it's a high style, hand-eye, muscle memory task and that's why they pay us the big bucks atmo.

Just finished this one this morning
joined to the white Dove's INOX "Cadenzia" tubi

[shand]

I always slot on an angle and keep the dropouts straight. Don't know why, always done it that way. Most I do on my lathe, some I do by hand. Doesn't make much difference time wise and the deciding factor is usually what's set up on the lathe and how long it'll take to bolt on my milling vice!

I used to use a couple of saws on with a spacer but found a big old thick mother that would work in one pass if I took it slow.

some info here:

http://www.shandcycles.com/slotting-stays

[Clockwork]

I always slot on an angle and keep the dropouts straight. Don't know why, always done it that way. Most I do on my lathe, some I do by hand. Doesn't make much difference time wise and the deciding factor is usually what's set up on the lathe and how long it'll take to bolt on my milling vice!

I used to use a couple of saws on with a spacer but found a big old thick mother that would work in one pass if I took it slow.

some info here:

http://www.shandcycles.com/slotting-stays

Steven-

What RPM are you running when you slit stays with your lathe?

Thanks, Joel

[shand]

Steven-

What RPM are you running when you slit stays with your lathe?

Thanks, Joel

Hey Joel,

normally the lowest (non-backgear) speed, which I think on my Super7 is about 250RPM. I'm pretty bad a remembering things like that though so I'll check for sure later. I know it needs to be slow and since I started using the single saw rather than a pair with a spacer, the feed rate needs to be very slow. I don't have power feed on the cross slide so I just take it very easy and make sure there's always positive pressure being applied. Works fine and no need for any clean up other than a touch of shop cloth.

Steven

[marten]

Steven-

What RPM are you running when you slit stays with your lathe?

Thanks, Joel

250 rpm will be way too much.
A normal cutting speed for HSS (ie 25-30 m/min) will work out at around 100 rpm, depending on the diameter of the blade ofcourse.