StealthHitches :: DIY 3D-printed Solution :: "Dremel Cutting Guide and Covers"

[AEtherScythe]

I'll lead with three pictures:

Now for the background...

Last fall I purchased the following hitch for use with a bicycle rack:
https://stealthhitches.com/products/ford-hitch-shr11001

There are quite a few posts about that hitch and others.
Some of the photos made me nauseous (no offense to anyone), and I was loathe to actually go through with cutting a hole in the bumper cover of our 2021 MME FE! :S

I chickened out and stalled, just long enough that installation became moot, because we ordered a 2023 MME GT PE. So the hitch sat in the box for a few months.

Finally got the new MME GT PE just before Christmas (see here), but I was still very apprehensive about cutting the bumper cover. :S

Saw this post where someone who bought a different hitch was looking for suggestions for how to cover the cut-out in their bumper cover, whether 3D printed solution or other. However, I realized that there isn't much hope of a one-size-fits-all cover, given that every hole in every bumper cover is going to have a lot of variability due to no standardized method of cutting. :S

That's when it occurred to me I could solve this problem by first designing a Dremel cutting guide, and then designing a cover to fit the hole cut using the guide. Ultimately I made a second version of the cover for added protection against the elements even when the receiver is installed.

A few weeks of prototyping later and I'm done!
Huge thanks for the help from the fine people at @AOSK who supplied this model, which I used the basis of a "cutting tool" to get the contour of the MME bumper cover just right.

Here is the Dremel Cutting Guide:

And here are a few more pictures...

As always, I offer my work for free, for NON-COMMERCIAL USE.
You can find the 3D parts and installation notes, over here:

https://www.thingiverse.com/thing:5847251

If you can't print these yourself and someone else does it for you, it's fine for them to recover their time and materials, but they should not be charging a penny more.
Folks have violated this in the past and if it keeps happening I'll simply stop sharing my designs. PERIOD.

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[AEtherScythe]

And before anyone asks...

These covers won't work for holes cut by any method other than using the included Dremel Cutting Guide.

Even if you have the very StealthHitches model hitch, the measurements most certainly will NOT be the same. One reason is that I had to take a few liberties to make the cutout slightly smaller so that the covers would fit on my 300x300 print bed.

 

[HuntingPudel]

First off, congrats on the new GT-PE! ??

Thank you for donating your time to the community. I probably won’t use this specific item, but I LOVE the charge port door travel limiter. ????

 

[Seth]

Amazing work! That looks absolutely fantastic! There is no limit to the ingenuity I see from people. Thanks for your contributions.

 

[silverelan]

That's a sweet bike! Looks fast not even moving. Nice job on the rack install too.

 

[AEtherScythe]

That's a sweet bike! Looks fast not even moving. Nice job on the rack install too.

Thanls! It's a 2016 Madone w/ ~64,000 miles on it. Overdue for replacement. That's more miles than carbon fiber is intended to withstand, especially having been subjected to Michigan's crater every two feet crappy roads for the majority of said miles! :-/ #FixTheRoads!!!

 

[silverelan]

Thanls! It's a 2016 Madone w/ ~64,000 miles on it. Overdue for replacement. That's more miles than carbon fiber is intended to withstand, especially having been subjected to Michigan's crater every two feet crappy roads for the majority of said miles! :-/ #FixTheRoads!!!

That's a hella lot of miles. Nice to see someone else hasn't made the switch to discs yet either. That'd be pretty fast even today in the Cat 1/2 field.

Any concerns with the cutout in the diffuser keeping out dirt/water/schmutz?

 

[ksroskel]

And before anyone asks...

These covers won't work for holes cut by any method other than using the included Dremel Cutting Guide.

Even if you have the very StealthHitches model hitch, the measurements most certainly will NOT be the same. One reason is that I had to take a few liberties to make the cutout slightly smaller so that the covers would fit on my 300x300 print bed.

any chance this could be printed on a 270x200 print bed?

 

[AEtherScythe]

any chance this could be printed on a 270x200 print bed?

Sorry, but no chance. The covers are 296mm in the long direction and only fit on my Lulzbot TAZ Pro, because I know how to hack the start G-Code to let me print all the way to the edge of the 300x300 surface (normally it maxes out at 282x282),. And of course the Dremel Cutting Guide is even larger, so I had to print it on my Craftbot FLOW IDEX (XL).

EDIT: I should note that the StealthHitches installation guide is calling for a 11.5" cutout, e.g. ~292mm, and the cover has to be larger than that in order to have a "lip" to keep the cover from pushing in through the cutout.

EDIT 2: I suppose if you have very small hands, you might survive with a cutout that is only 10" wide, e.g. 254mm, and with a 6mm lip that would fit on your bed.

The cover might be made to fit your bed (if your hands are small), but what are you going to do about the Dremel Cutting Guide, which is at least 60mm longer?

 

[AEtherScythe]

That's a hella lot of miles. Nice to see someone else hasn't made the switch to discs yet either. That'd be pretty fast even today in the Cat 1/2 field.

Any concerns with the cutout in the diffuser keeping out dirt/water/schmutz?

I'm not sure I follow the question. The cutout has been filled by the covers now, both with and without the hitch receiver installed. I did wonder if I had made the covers' retaining flanges "robust" enough to prevent the covers from getting "sucked out" at freeway speeds, but I put it to the test for > 30 minutes at above 70 mph and there were no issues. It was a bit of a fine line to traverse, wanting the flanges to be stiff enough to do the job, but not so stiff as to make it onerously difficult to install the covers.

 

[TheVirtualTim]

That's a hella lot of miles. Nice to see someone else hasn't made the switch to discs yet either. That'd be pretty fast even today in the Cat 1/2 field.

Any concerns with the cutout in the diffuser keeping out dirt/water/schmutz?

Now that you point out the brakes ... if you look carefully at the front brake you'll see that it's completely aero and you can't see the cables. All of that is hidden inside the head-tube of the frame. But the problem that created is that the forks and brakes have to turn independent of the head-tube. So Trek designed spring-loaded "flaps" on the left and right lower edge of the head tube. As you turn the handlebars, the "flaps" open to give the brakes space. When you return the handlebars back to the straight direction, the flaps close and the frame is totally aero again.

I've never seen anything like it on any other bike. It's pretty cool. Trek likes to hide little Easter Eggs on their bike ... when the flaps open it exposes a little pirate skull & crossbones.

 

[AEtherScythe]

I've never seen anything like it on any other bike. It's pretty cool. Trek likes to hide little Easter Eggs on their bike ... when the flaps open it exposes a little pirate skull & crossbones.

#OffTopic, but okay... ;-)

Don't get me wrong, I love my Trek Madone, but that brake design couldn't be worse from a serviceability perspective. There are something like 50 different parts, including some completely custom, piggy-back, bolts where the bolts go in, and they have a socket for another bolt to go in on top through the back of the other bolts.

To make matters worse, even with Loctite, the bolts tend to fall out over time (due to aforementioned bumpy roads) and since they're completely proprietary they can only be sourced at a high price from Trek. Further, it's only a matter of time before the (proprietary) brake parts will no longer be available, due to discontinuation of the 2016 design.

On top of all of that, these brakes are a royal pain to adjust -- there isn't a barrel style adjuster, so you have to get the cable length exactly right, and then if it stretches you have to loosen the retaining screws, move the cable and retighten it. You have to get it exactly right, because if the cable sticks out of the retainer even a millimeter it will scrape the tire. :S

I couldn't hate these brakes more! I would set my alarm to get up an hour earlier, just so I can hate them another hour each day. ;-) But I love the bike overall. LOL

 

[Avelli]

Design idea- instead of a rectangular cutout, perhaps a stadium-shaped cutout. Installation would be a lot easier with a specified hole saw (just need to define the centers for the hole saw in the template), and two straight cuts to create the flats. This removes the tricky corner cuts on the rectangle, plus any weak points in the hole.

Also, I just found out that "stadium" is the correct geometric term for what I've always considered an oval (i.e. horse track).

 

[AEtherScythe]

Design idea- instead of a rectangular cutout, perhaps a stadium-shaped cutout. Installation would be a lot easier with a specified hole saw (just need to define the centers for the hole saw in the template), and two straight cuts to create the flats. This removes the tricky corner cuts on the rectangle, plus any weak points in the hole.

Also, I just found out that "stadium" is the correct geometric term for what I've always considered an oval (i.e. horse track).

The design is based on the manufacturers instructions. I'm not connected to the manufacturer and when I started this I hadn't installed one of these hitches before, so I wasn't going to take liberties / stray from their instructions. They called for a rectangular cut and that's what I made.

But now that I've done it... Sure, it would be easy to radius the corners and wouldn't affect the installation nor function at all.

I'm backed up on projects, but if there is sufficient interest I could easily make the modification, but beta testing it would be completely on the part of someone doing the asking. And there would be costs involved unless they're prepared to print all the parts themselves.

 

[MurphyDog]

Does anyone have the dremel cutting guide printed that they could lend me? I'm in California and would cover any shipping costs (I can send pre-paid UPS label). I'm having the Stealth Hitch installed next week and would LOVE to provide the cutting guide to my installer. I'll then get the covers printed at a later date.

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