Scuttle removal?

[JohnCh]

I'm planning to make my scuttle removable by replacing the 24 rivets with M4 dome head fasteners and rivnuts.  For those who have already done this, how did you remove the old rivets?  I'm used to drilling out the center then letting the remaining rivet head "ring" fall off.  However, Caterham paints over the rivets meaning those rings stay in place. 

 

As someone accident prone by nature, I'd prefer not to use an oversized drill bit and carefully wear down the rivet heads.  Even if I make a jig to limit drill depth, with 24 chances to make a mistake, I probably will.  Is there any reason not to simply drill out the center with a drill bit also the correct size to create the through hole for the M4 fastener and leave the rivet head ring in place under the paint?  The only one I can see -- and it is a concern if realistic -- is some ring could rotate when tightening the fastener and crack or tear the surrounding paint.  

 

Thanks,

John  

[sltous]

Hi John,

 

I'm in the process of making this change now, I went with a larger drill bit (a #24) and drilled the rivets out (heads 'twisted' off and all 24 are lined up on my drill bit) but I was not too worried about my paint inside the engine bay where the scuttle meets the bonnet.  I imagine you could do something like using a small hole punch or a knife to scribe around the head of the rivet to break the ring of paint before drilling so you got a nice bare aluminum ring rather than chipping or tearing the paint.  I don't know a ton about rivets but I think unless you used a sheet metal drill bit the thin wall of the head of the rivet is always going to twist when the bit breaks through and pull off.

 

My plan is to re-fit using low profile aluminum rivnuts https://www.mcmaster.com/91230A221/ and plastic screws in order to save on weight. I am basically treating the mounting of the scuttle as a cosmetic piece under virtually no load.

[JohnCh]

Thanks @sltous, this helps.  I toyed with scribing around each rivet but that seems like a lot of work that may not be necessary.  Did you get chipping in the paint when the heads spun loose?  If so, was it minor and sufficiently close to the rivet head that it could be easily covered by the fastener head or a washer?  

 

Those are the same rivnuts I'm planning to use.  I hadn't considered plastic screws but also haven't looked at how the rest of the scuttle bolts to the chassis.  Something to consider for my McMaster Carr order.

 

Thanks,

John

[IamScotticus]

If the rivets aren't pull through, (they will be hollow in the middle) then drilling through the metal shank, or anvil, is asking for trouble. 

Otherwise, scribe around the head and let it fall.

[sltous]

50 minutes ago, JohnCh said:

Thanks @sltous, this helps.  I toyed with scribing around each rivet but that seems like a lot of work that may not be necessary.  Did you get chipping in the paint when the heads spun loose?  If so, was it minor and sufficiently close to the rivet head that it could be easily covered by the fastener head or a washer?  

 

Those are the same rivnuts I'm planning to use.  I hadn't considered plastic screws but also haven't looked at how the rest of the scuttle bolts to the chassis.  Something to consider for my McMaster Carr order.

 

Thanks,

John

Taking into account my plan for use of washers with outside diameter 9mm https://www.mcmaster.com/97763A822/, on my car which has been repainted at least once, there are definitely chips that will be visible outside the diameter of the washer.  (Mis)Using a 9mm wrench instead of calipers, see some pictures.

[IamScotticus]

Is there a leather hole punch the head diameter? if so, you could serrate the cutting edge and spin it around the head for a clean paint cut

Edited October 31, 2022 by IamScotticus

[JohnCh]

@sltous thanks for going to that extra trouble.  I just made an attempt at scribing around a rivet and it's a lot harder than it sounds.  Even with lots of blue tape, no way I'll get through 24 of these without some slips and gouges on the fresh paint.  I know Bruce Beachman did the rivet removal on CatKong and I've asked him to confirm the process.  At the end of the day, building a simple depth stop jig and using a drill bit the same diameter as the rivet heads (5/16") might be the best combination of speed and damage minimization.  

 

-John

[IamScotticus]

https://www.etsy.com/listing/761527011/05mm-25mm-round-hole-punch-leather-hole?click_key=99999274c1ea6f85fc8c9df7885bda9ac61f8cc6%3A761527011&click_sum=12e1e3a9&ref=internal_similar_listing_bot-1

[sltous]

5 minutes ago, JohnCh said:

@sltous thanks for going to that extra trouble.  I just made an attempt at scribing around a rivet and it's a lot harder than it sounds.  Even with lots of blue tape, no way I'll get through 24 of these without some slips and gouges on the fresh paint.  I know Bruce Beachman did the rivet removal on CatKong and I've asked him to confirm the process.  At the end of the day, building a simple depth stop jig and using a drill bit the same diameter as the rivet heads (5/16") might be the best combination of speed and damage minimization.  

 

-John

Happy to help.  Let me know if there's any other scuttle or sub-scuttle structure information I can share while I have mine on the shelf, keeping in mind I have a 2005 car and it may have changed somewhat.

[JohnCh]

Thanks @sltous, I'll let you know if I need anything else while your scuttle is off.  

 

@IamScotticus the leather punch would certainly be safer and cleaner than razor blade to score the paint. 

 

Hopefully I'll hear from Bruce soon since he went through this recently with Croc's car.  Searches on Blat Chat haven't helped.  In the results I've found, people simply state "drill out the rivets."  It makes me wonder if I'm overthinking this or too risk averse.  If the paint wasn't fresh or hard to match, I'd be more prone to experiment, but after waiting nearly a year and a half for the kit, I'd rather not rush into an Oops moment in a visible spot.

 

Thanks,

John

[MV8]

A dremel with a 1/8 shank carbide double cut ball would be quick and easy. A small area can be touched up easy with auto touch paint with a brush cap.

[JohnCh]

I don't trust myself doing that 24 times without error, and this paint is not something I can easily match with auto touch up paint.  It's a pearl that is only offered by the factory as a paint-to-sample upgrade from their back catalog.  If I do need to grind down the remaining rivet heads, I'd prefer to do so with a depth jig using a shallow pitch drill bit.  It feels more consistent and takes a shaky hand out of the equation.

 

Thanks,

John

[IamScotticus]

consider removingthe paint from the headsas close to the edges as possible with a thinning agent.  then drilling wirh the painted edges still soft from the thinner.  when the rivet head comes loose the paint will have a soft edge break and lay down to cure.

Edited November 1, 2022 by IamScotticus

[11Budlite]

John - It's been a while so I can't give you more detail with the size of drill bits that I used, but it was a simple operation and came out very well. One drill bit for rivet removal and one for the nutsert install. I don't recall knocking out the mandrel before drilling out the rivet. The button head screw head covered the missing paint from rivet removal perfectly. No issues with my BRG paint after rivet removal. I can't imagine doing any wiring work behind the dash without removing the scuttle first. I've had mine off 3 times already.

[JohnCh]

Thanks @11Budlite, it sounds like the current paint is thin enough to avoid coming off in bigger pieces like @sltous saw.  I'll give this a shot later today with one rivet and see what happens.  If the flaking encompasses too large an area, I may pick up a leather punch as per @IamScotticus's suggestion and use that to score the paint immediately around the rivet head.  The scuttle is definitely coming off one way or another, I just want to avoid visible damage.  

 

Thanks,

John 

[JohnCh]

I just ran down to the garage and confirmed I've been over thinking this and hyper-paranoid for no reason.  With blue tape covering the rivet area, followed by running my fingernail around the perimeter of the rivet to ensure a good seal with the tape, then using a 3/16" drill bit at very low speed, the 5 rivets I drilled out came out perfectly with no paint damage.  I'll finish the job later and takes some pictures.  Thanks again to those who responded!

 

-John

[JohnCh]

I spent 10 minutes in the garage drilling out the remaining rivets.  The first 19 went smoothly, but the next two left the rivet head in place.  Carefully scribing the paint around the circumference followed by a slight tap was sufficient to knock them off without any damage.  Glad I didn't have to attempt that for all 24.  I'll update my build thread later once the scuttle is removed.

 

 

-John

[JohnCh]

I didn't realize there are two more rivets that attach either side of the scuttle to the dash tube (thought those were small dome head screws.)  @sltous and @11Budlite how did you handle that?  Can you put a rivnut in that tube?

 

 

Thanks,

John 

[11Budlite]

1 minute ago, JohnCh said:

I didn't realize there are two more rivets that attach either side of the scuttle to the dash tube (thought those were small dome head screws.)  @sltous and @11Budlite how did you handle that?  Can you put a rivnut in that tube?

 

John - I put an M3 rivnut and button head screw in that location. So far it's worked out fine.

[IamScotticus]

Someone will eventually hit a foot or knee on the scuttle edge exiting and bend it.  That is an expensive and disheartening occurrence .

Putting a rivnut there in the chassis is one of my goals too, but perfectly locating the drill hole on the scuttle edge in front of the chassis hole is difficult because its hidden.

 

The only thing I have found to help solve this are these

On Amazon they can be found under "Dowel and Tenon Center Transfer Plugs" but they are made for sheet metal applications in smaller size, but getting harder to find