[febikes]

I like Paragon flanged sliding dropouts but there are somethings about working with them that is frustrating. This is mostly a repeat of stuff on my blog but I hope sharing it here will be helpful to others and facilitate a discussion that will help me improve my process.

It starts with dropouts | Farnsworth Elemental

In particular, the miters is hard to get perfect. I have setup a fixture where I rough in the miter but I still end up needing to tune it. I want the sliders to be level when the frame is complete and in hindsight need to adjust the design of my fixture to support this. For now what I do is set it up close in the jig then work with a file to make it perfect. Redesigning the fixture will take time so if you have ideas and/or photos of your fixtures for this please let me know.

The way the flange is shaped the chainstay will not hold in place so in addition to the tight miter I need to steady things with one hand and then fusion tack with the other. I am not sure what others are doing but fusion tacks like this are stressful. I am thinking of a modification to my fixture to provide a way to hold this for the tack and/or setting up a dedicated JIG for making the tack on this.

The following is a crappy photo but, I like the look of these dropouts vs. the plate style ones.

In any case, thanks for looking and let me know if you have any comments or tips about working with these dropouts.

 

[febikes]

Duh; I hate it when I do stupid stuff!

I just realized this morning that while one of the dropouts went on great I somehow goofed up and did one of them upside down.....

On the first dropout I had things perfect but then somehow when I was setting up things in the fixture for the second dropout I flipped it over. You can see this in the photos above where the one with the little tack is actually correct but the bottom photo of the fully welded dropout is actually upside down...

Stupid happens

 

[Walt]

I don't usually use hooded dropouts but in general, if you can't find a way to keep everything in place with magnets, rubber bands or even tape are great for tacking. Find a way to make everything stay where you want so you can concentrate on the tack/weld instead of having to hold it all together with your free hand.

Your fixture looks pretty much like what I would do - why is it that you can't level the slots with those miters? Doesn't the hooded portion allow you to rotate the dropout around the miter on the stay to some extent?

-Walt

 

[febikes]

I still can't believe I goofed up and put the one drop out on upside down for setup. In any case it just gives me a chance to do it again and get it right. The silly thing is that I actually made the same mistake on one of my other frames but for that build I just did both upside down to match.

In any case it gives me a chance to start over and refine things to get a better setup.

Find a way to make everything stay where you want so you can concentrate on the tack/weld instead of having to hold it all together with your free hand. I don't usually use hooded dropouts but in general, if you can't find a way to keep everything in place with magnets, rubber bands or even tape are great for tacking.

Ya, for some reason I just can't seem to get a good positive force with magnets, toe straps, bands, etc. Really would love to see some photos of this sort of setup. I have managed on all my builds but am still not really super happy with setting up for this tack. There are ways to "get it done" but they don't feel super precise.

Your fixture looks pretty much like what I would do - why is it that you can't level the slots with those miters? Doesn't the hooded portion allow you to rotate the dropout around the miter on the stay to some extent?

The fixture I built "works" but I think it needs to be redone to get the level of accuracy that I want. In particular the bottom bracket vs. the dropout has "bb drop". With BB drop the slot for the slider needs to be made level with the ground for when the bike is built so it's not really inline with the chainstay. In addition the way the flange is made the cut must be pretty well aligned although getting close works then following up with a file to make this perfect. The fixture works but it is very much a 1.0 design and needs to be refined a bit.

 

[smudge]

what frame fixture are you using? Do you have something like the "support bar" on the Anvil?

First I'd suggest that you keep meticulous notes on your slider builds (I'd suggest every build actually) so you can keep track of things like BB drop and miter offset. After five or six different frames with different BB drops you should have a pretty good idea of what offset is doing to work with the miter on the bottom flange.

One of the few uses I have for that extraneous Anvil fixture arm is to use it as sort of a stay tacking fixture. I'll load the dropouts into the fixture and use the arm (with a wide plate bolted to the top of it) to support the stays while I line up the miter with the dropout. I have some thick rubber bands that I use to keep them in place and if they're being stubborn, I'll use a pony clamp.

I try to choose a reference surface when a single item has to go through multiple steps. For example, I have a little fixture that I use to set the angle of the miter for the D.O. and it uses the S bend in the stay to orient itself when clamped in the vise. I use the same side of the stay to lay on the plate on my Anvil fixture arm and more often than not, it self references on the bottom plane of the stay because the S lays flat on the plate. All I have to pay attention to is setting the miter angle tight to the D.O. before the stay is clamped.

For me, the bigger issue with sliders is the loose fit between dropout and dummy axle and that the weld face is so far from the axle. More time than preferable is spent setting each dropout just so to prevent them from being at slightly different angles which goofs up fitup and can lead to the rear wheel axis tilting on adjustment. As usual, I made a tool that removes that step (but adds others) from the process. It's a very rough prototype, but it works perfectly.

Untitled by VertigoCycles, on Flickr

 

[febikes]

what frame fixture are you using? Do you have something like the "support bar" on the Anvil?

I have the HJ fixture and it does not have a support for this operation.

For me, the bigger issue with sliders is the loose fit between dropout and dummy axle and that the weld face is so far from the axle. More time than preferable is spent setting each dropout just so to prevent them from being at slightly different angles which goofs up fitup and can lead to the rear wheel axis tilting on adjustment. As usual, I made a tool that removes that step (but adds others) from the process. It's a very rough prototype, but it works perfectly.

Untitled by VertigoCycles, on Flickr

Very nice!

I made a similar fixture at one point but I like yours better.

Right now I am using the 142x12 TA axles and with the anvil through axle the indexing of the dropouts is pretty close. I machined the top of two dropout inserts to provide a reference plane.