need a 26mm PCB / driver board / contact plate

There really doesn’t need to be a 20mm version cause there are already 20mm 7135 and FET drivers.

Be prepared and have the option of any size or configuration contact board at your fingertips.
DIY Contact Board Tutorial

How about 26mm DD fet driver for 9T6 or TR J18 ? :slight_smile:

This is the contact board. You can even adapt the setup to the given space and solder the driver on the inside or the outside of the contact board, depending on whether you need more space in the driver hole or on the battery side.
I’m new to PCB design, so 2 questions come to mind.
When I order this, is the inner 18mm part loose or do I need to saw it out?
Is the outer ring completely copper plated but partially unexposed? At first glance it seems there is no contact between the copper plated parts.
Thanks for designing this.

Oshpark’s project creation process says that they do not officially support cutouts but that they “usually” work anyway. That’s probably what you are thinking of. The specs page says that they officially support cutouts and that’s the one to believe.

For an SRK the diameter of the driver he wants to use along with the contact plate really doesn’t matter, the battery + ring must be very large so an SRK should really use a traditional contact plate. That’s getting pretty expensive for a contact plate though…

Plus IOS and FT both sell 20mm contact boards.

even though it’s been up recently I’d already forgotten about your tutorial. Of course that’s a more truly budget option than mine! Thanks for reminding us. If you had leftover sheet copper or scraps of copper pipe to unroll I suppose they could also be used with a little extra grunt work.

Thanks HarleyQuin. It is not obvious from the Oshpark renders, but both sides are 100% flooded with copper. The vias are plated of course, but the center cutout is not plated. Oshpark specs don’t allow that. Of course that’s only an aesthetic problem, there is plenty of electrical path by way of the vias. I guess I should have specified for it to be plated and waited to see what happens - they’d cut the hole whether they plate it or not. The purple areas are covered in resist, it’s there primarily to help keep from making a mess while soldering. With the resist ring you should be able to keep solder away from the ledge for a nice clean fit in a driver pocket.

You should not need to cut out the center. It’s drawn on the renders, but you shouldn’t receive it. It is marked to be cut out with a milling tool and it does not have tabs to keep it in place.

Thank you very much, wight, that clears matters up for me.

I fiddled around with pipe tube parts in the past, like adding several concentrical rings to a 17mm driver. It works, it’s budget, but your approach is way better.

I downloaded Eagle in the meantime, but it seems you have a different file format. Is there a software (preferably free) to make or alter these PCB designs? You just opened a can of worms here. I can well use the 26mm variante, but I could need 23.7mm (Maxtoch HI6X-17) and 22mm (Ultrafire F10). Oh this might come in handy…

Edit:
This had been my approach till now, yours is slightly more sophisticated… :slight_smile:

PCB manufacturing uses a format called Gerber. That’s what those files are. I did use Eagle to produce those layouts, the appropriate files for Eagle are .brd files:
http://photo.jesusthepirate.com/blf/26mm_contact_board/

Note that v4 are what I shared on Oshpark. v6 uses an unsupported drill size to create a large via (plated hole) instead of a routed hole. v6 may or may not actually work :slight_smile: The PCB house used by Oshpark specifically does not support plated slots on these boards, but who knows if you could get away with specifying a giant drill hit (16-18mm) and via.

Wow, thx for the link to the brd-files, I was able to open these in Eagle (v6, though).

The program is, well, err, mildly intuitive… but I was already able to move some vias.
I found Mattaus Eagle Tutorial, that’s exactly what I need right now. :slight_smile:
I’m thinking of placing the vias closer to the center and all copper visible, so I could grind down any 26mm board to a needed size. Still easier than my last approach or having 18 and a half different board sizes to design.

Your board looks slightly different in Eagle than at Oshpark. So you designed them in Eagle, how did you upload them, as .brd or somehow pre-converted?
At Oshpark other boards are sometimes .zip (Gerber?) but also sometimes .brd, that still puzzles me.

To make gerber files out of eagle brd files you use Eagle’s CAM processor. Oshpark has an Eagle CAM processor built into their site, so it is possible to upload .brd files directly. When sending to other places you typically must provide gerber files. Doing the CAM processing yourself helps make sure that the Eagle file is interpreted the way you want.

I did intend to link you to Mattaus’s Eagle tutorial, but I forgot. Good thing you found it yourself.

Eagle’s presentation of boards is different from Oshpark’s. For one thing, Eagle shows you the mirror view of the bottom side, Oshpark does not. Not such a big deal here of course since the whole board is symmetrical :wink:

Leaving off the solder mask is fine. I actually took it off myself and then put it back for the reason I mentioned above - to clean up the soldering process a bit. Note that you can move items parametrically by right clicking and editing the Properties of any given item. That will allow you to directly set the X and Y coordinates for precision placement.

Harley if/when you do a 22mm one please post it here, I need one for my balder clone.

I was thinking of doing breakaway tabs for a more flexible contact board, but never made it that far. Instead I made this 22mm contact board.

16mm tabs for 17mm driver or file to match outer radius to get a 18mm circle for a 20mm driver.

EDIT: those are the tightest turns you can make at Oshpark. They use a 0.1in endmill for the cutting.

It depends on the CAM processor, if someone uploads a .brd file OSHPark renders the file then generates their own gerber files for the manufacturer, pre-generating and zipping for them just skips the step of them having to convert .brd to the CAM files (gerber) files

Mattaus’s CAM processor is so easy to use…just design the board, open the cam processor, load the board, hit the generate button, zip up all the *.CAPLETTERFILES in the directory and viola…instant zip file ready for OSHPark (I added a top and bottom paste layer to his processor so it will have the cream layers to work in OSHStencils)

That’s pretty cool…a modular type contact board

Err, the more I think about it the more I wonder whether that latest board I posted would be sturdy with a 17mm driver installed. The contact patch should be approximately 8 linear mm (2mm long across each tab) by 0.5mm deep. So ideally you are getting… 4 square mm of soldered contact area. As long as the traces on the 17mm PCB don’t lift/tear I guess it’s OK.

Maybe if you had extra tabs at 12 and 6 oclock, more work to fit…but would really increase the area for soldering to the ground ring, much more rigidity and strenght

Some 17mm drivers have very narrow GND ring. BLF17DD for example.

Wow, I’m still trying to find the bottom layer in Eagle, and you bring up truly fancy stuff here.

If you could
a) extend the 4 inner lips just so far, that a 17mm driver can be put on top instead of being soldered planar

- then you have the option to file it down to 17mm if you want it planar, but you needn’t. I second the idea for a 5th and 6th lip.
b) extend the whole piece to 26mm while keeping the vias exactly there.

  • then you can grind it down to any diameter between 26 and about 22.

That would be a very variable board for 17 to 20mm driver and 22 to 26mm outer diameter. PCB can be shortened with a dremel and a sanding piece in no time.

Just a thought.

As long as I’m in Eagle…

Would you want guide rings?

The inner tabs already extend to 16mm diameter. As I mentioned, 15mm would cause a problem for BLF17DD and similar I think (?).

The tabs were a big pain and not flexible the way I was doing them. I did some new tabs a different way.

Oh yes that’s truly helpful. Now I start to understand where all these cool Oshpark projects come from.

Sure…

What are guide rings? :slight_smile:

In response to your earlier comment - yeah, Eagle is the the devil. It’s super-not-intuitive. Somehow I’ve started to get used to it. I have also messed with Kicad some, it was different but not better.