Insulation Problems

[Mr. Delirium]

The latest project that I've been working on (and my first pen build) has been a ~150mw red laser pointer that uses the Mitsubishi LPC-840 along with an AMC7135 current regulator.

Problem:
Both the negative and positive connections from the batteries must go through the AMC7135 to properly drive the diode

As you can see, the diode is case negative. I knew this going into the project and assumed that I could use some kapton tape to insulate the 12mm module from the host. My hosts happened to be the amazing leadlight hosts from Laser66 which happened to be machined to have an ID of exactly 12mm. I wasn't expecting such tight tolerances, but it's definitely a testament to the quality of Laser66 products.

This makes it impossible to fit into the host, I have tried sanding this thing down for about an hour now and I don't think it's going to work.
If any of you have tips on how to maybe insulate this a different way, insulate the diode from the module, or recommend some cheap drivers, I'm all ears. Worst case scenario I buy some more pricy drivers. This was supposed to be a very cheap build so I'd like to stray away from that.
All help is appreciated

*If you got the notion that I was dissing Laser66 products in any way during this post that was not my intention, I genuinely like their products. Sometimes my thoughts aren't as clear as I would like

 

[405nanoMatt]

Use something tapered as a mandrel and flare out the end you need to put the module in. Needle nose pliers usually get the job done for me.

 

[Alien Laser]

I build many of this pen laser's it's tricky to get it in all the way but it's possible see mine video's
i will update some of this video's using mine camera.

 

[Mr. Delirium]

I build many of this pen laser's it's tricky to get it in all the way but it's possible see mine video's
i will update some of this video's using mine camera.

beautiful lasers, did you just sand down the interior of the host, or maybe the module?

 

[Mr. Delirium]

Use something tapered as a mandrel and flare out the end you need to put the module in. Needle nose pliers usually get the job done for me.

Sadly I do not possess a lathe

 

[405nanoMatt]

Neither do I . I do it by hand . Either with a cordless drill with a half inch chuck or a pair of vise grips.Just secure the host and insert whatever makeshift mandrel I have on hand that is the proper size and slowly turn while applying downward pressure.

 

[Mr. Delirium]

That's inventive, I'll try that