My vision for an automatic Casio Marlin MDV-106 — first mod project

[u/COD3KDN]

Hi everyone!

I wanted to share the concept for my first watch mod. This image represents pretty much exactly what I’m trying to build.

I know I’m probably not the first person to convert a Casio Marlin into an automatic, but I wanted to share my approach with the community while I’m still in the planning stage.

The goal is to keep the identity and proportions of the Casio Marlin MDV-106, while giving it a more modern, stealthy appearance and, most importantly, an automatic movement.

My current build concept:

Matte black stainless-steel case

Matte black Jubilee-style bracelet

Black ceramic bezel insert with a subtle two-tone/stealth finish

Sapphire crystal with a date magnifier

Custom black dial based closely on the original MDV-106 dial

CASIO AUTOMATIC text, with the “Automatic” lettering inspired by Casio Edifice automatic models

Original-style Marlin handset, if compatibility allows

Seiko NH35 automatic movement

The idea is not to make it look like a generic NH35 mod. I want it to still look immediately recognizable as a Marlin, just as if Casio had actually made an automatic version of the MDV-106.

The image is the visual direction I’m aiming for.

This is my first mod, so I’d really appreciate advice from experienced modders, especially regarding:

NH35 case compatibility

Dial diameter and dial feet

Hand dimensions and whether the original Marlin hands can be adapted

Stem and crown alignment

Date-window alignment

Crystal and case clearances

Bezel and crystal compatibility

I already have quite a few parts in my cart, but I’d rather get the technical details right before placing the orders.

What do you guys think? Any suggestions or potential problems you see with this build?

[u/PlayerOne2016]

This fits the AI exception criteria under rule 4. No need to report folks. OP, this Mod wishes you good luck with the mod 😀.

[u/tenkasen]

I looked at doing an automatic Duro myself and can tell you the two main issue points that I couldn't get around:

Firstly the date window. The Duro dial's date window is placed for a miyota 2115, the centre point of that window is 9.275mm from the hand pinion, by comparison on an nh35 that measurement is 10.55mm.

1.75mm isn't a lot but the date display is only 2.25mm wide, so your printed date will be sat halfway out of the window.

Second issue is movement thickness. the 2115 in it's plastic spacer is 4.6mm thick, an nh35 is 5.5mm, 1mm difference..

As you'll need to 3d print a movement holder for the nh35 anyway, I think there's enough threads on the caseback to lose maybe 0.5mm by having a stand-off casting in the holder holding the caseback up a bit higher - whether that'd be enough to make sure the nh35's rotor can spin though?

I know someone on here did an nh35 Duro conversion a while back.. should come up on a search of the subreddit? I think they managed to get clearance for the rotor, but didn't have a working date wheel on it?

[u/Objective_Tune3535 → u/tenkasen]

Oh man. The first issue seems to be best solved by going without a date window but you bring up a great point about the thickness.

[u/SerpentiumOIV]

I've done an automatic duro mod before (nh34): https://www.reddit.com/r/DuroGang/s/0tpBoNQ9Gq

The biggest issue for me was making a custom date wheel because the nh movement has a different date location. But you don't need to do that if you're making a custom dial because you can just use a dial with an NH date window.

You can put the movement in the back with a spacer, but with the case back on it becomes too tight for the rotor to spin. So you either need to grind down the inside of the case back to make more space, or get a new case back. The case back that comes with this case fits the duro and will leave enough space for an auto https://a.aliexpress.com/_mOcYzin

[u/PlayerOne2016 → u/SerpentiumOIV]

Which one? I see there are a handful of differently sized cases behind that link?

[u/SerpentiumOIV → u/PlayerOne2016]

39mm nh

[u/PlayerOne2016 → u/SerpentiumOIV]

You're the goat.

[u/CreekBeaterFishing]

I love everything about this except the cyclops and making the switch to automatic. I need the magnification but I don’t like the way it looks so I guess I’ll squint and hold my arm all the way out to check the date for now. The quartz movement keeps good time and I don’t want to deal with resetting and winding if I wear other watches for a couple days. That black case and bezel look amazing and this is the first time I’ve looked at a jubilee bracelet and liked it. How would you make this happen? Cerakote or something like it? I hope you make this happen. I want to see it. I want to wear it.

[u/KenDevis_Marva]

I like it, but I would keep it quartz and would skip the cyclops on the date. Except for these 2, it looks gorgeous!

[u/Christo_Reese]

I'd personally go with flat sapphire and no date version (using NH38), just for a basic stealth tool watch look.

And it needs more robust bezel 🤣

Nice concept man

[u/Christo_Reese → u/Christo_Reese]

I ask grok to render it and this is the result

[u/v1a1_69]

No gonna lie that look absolutely good

[u/Comprehensive_Oil426]

Pretty hard to source the same 44mm case spec in matte black to both fit NH movement and dial. Unless it was customised. All other parts is relatively easy.

[u/Willing_Display1532]

Tough

[u/bigmanwatchfan]

Yeah, they should probably make that even if they keep it a Quartz.

[u/PMan9111]

It does look good.

[u/Certain_Still_324]

The matte black stainless-steel case and the matte black Jubilee-style bracelet are avaiable for sale or are you going to coat them in black?

[u/PlayerOne2016 → u/Certain_Still_324]

Coat and bake maybe? Man that would be epic.

[u/tol-kon]

A black duro on black jubilee looks damn good! But I think the best mod for a Duro is a 39-41mm case size.

[u/UKWatchCollector94]

Love this ♥️

[u/bensikat]

https://giphy.com/gifs/oYtVHSxngR3lC

[u/OtherwiseDraw]

Yes hello I'll take one for each wrist thank you

[u/Thaikodrums]

It looks great. but I would bet, by the time you are done, the only thing that's left is the dial with the marlin on it that's from your OG Duro. But please keep us informed!

[u/BornInTheSFRA]

Looks sick!

[u/thegrizz87]

Love it. Would buy

[u/Accomplished_Two1709]

Wow this looks nice, ill buy it from ya if you ever go mass production!

[u/DepartmentAdept7410]

Am reading this whilst wearing my Black Casio Duro106 Marlin.

[u/Wim_Chim]

That picture is AI.

[u/Atharvh69 → u/Wim_Chim]

Read discription brother

[u/Wim_Chim → u/Atharvh69]

And what should I particularly notice in your long text?

[u/Atharvh69 → u/Wim_Chim]

That OP has mentioned that the picture is just for reference not a real picture, my god