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Workshop operational tips. #22: Threaded MDF (POC).

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Blog entry by LittleBlackDuck posted 10-13-2020 12:56 AM 569 reads 0 times favorited 9 comments Add to Favorites Watch
« Part 21: Refresh the memory and Graffiti your tools. Part 22 of Workshop operational tips. series Part 23: CA-Finish “layers counter” for Pen turners. »

Boys and Girls,

It’s hard to imagine the blog I wrote about RivNuts was over 2 years ago. I was surprised by some of the comments saying they have been around for years, so I have to fess up that I didn’t discover them.
Whether they be called Rivnuts, Nutserts, pop-nuts or even beer nuts, it’s my blog so I’ll refer to these,

as Rivnuts…. and as I remember my youth, they also come in rubbers,

which I’ll refer to as rubber inserts, so we are all under the same blanket.

If you couldn’t be bothered to read the above link, the rivnuts are inserted using this setter,

For all you thrillseekers (politically correct way of saying skinflints) that don’t want to part with your shekels for a similar tool, you can always seat them using two spanners and a spare nut, or replace one of the spanners with a hex wrench… especially if the bolt has an allen head,


sorry, you figure it out (as I have the tool)... though I compare this method to popping normal rivets, with a mouth devoid of dentures.

I’m far from an expert and still coming to grips with the setter and the nuts,

I make a lot of jigs and workshop enhancements, and can see some use/benefit of threads in MDF.
As there hasn’t been a proliferation of coverage for these here at LJ’s, I thought I might get the ball rolling and share some of my findings to those that are unfamiliar with them. Any reciprocal education by seasoned users is/are eagerly welcome.

I haven’t used it enough to do a thorough review, however, the notion of threads in MDF made me think of rivnuts to see what I can achieve with them.

I have used threads in solid wood and wouldn’t go past The Wood Whisperer’s taps… they have tolerances designed for wood and are better suited than metal taps… in my opinion worth the extra shekels.

Unfortunately the nature of MDF precludes it from taking a thread and after buying a set of Wood Whisperer’s taps I had heaps sitting idle… I found that the two inserts below just don’t cut the mustard… or better worded, cut/ripped MDF,

The one on the left is the woodworkers common threaded insert that still requires a non friendly MDF thread, while the one on the right is the DIY hackers insert, which requires a hole and a hammer to drive it home… also not MDF friendly.

I believe that rivnuts are primarily designed for use for sheet or thin metal,

(up to 6mm… though some may work in thicker metal at higher bolt gauges). I wanted to extrapolate this concept to thinner sheets of MDF (like 3mm or 1/8”),

To set up this POC (Proof Of Concept), I designed a box using SketchUp as a “vehicle” to carry the rivnuts in MDF and see if it was viable.
Initially I was restricting my rivnut “popping” into 3mm MDF (more on this later), so I used my laser cut, dowel aligned, MDF lamination technique to build up a layer of 12mm thick MDF,


and laser friendly format,

Cut on the laser and then off to the workshop,

popped two rivnuts into the 3mm MDF

tested fit

and glued up with PVA using the dowels for alignment,

Cleaned up using flush cut, chisel and sander,


The four sides were then glued together using CA,

with the aid of the “tenon” cut layer of each laminated side,

I had no reservations on bolting something firmly flush against the “box”,

however, I did have concerns about pulling force on the rivnuts. While this is no great scientific experiment, I rigged this setup and managed to break the 6mm MDF I used when I continued to spread the clamps,

Still the same “scientist” operating the hardware, I rigged this larger piece of 6mm MDF to demonstrate forces in action by the bend in the 6mm MDF,

naturally unmeasured, however, I would be happy to trust it with lighter weights and forces.

I also toyed with the rubber inserts,

I made a video of this “box” and tried some basic tests and made a total arse of myself, wasting good footage in bastardising the use of these rubber inserts. I’m sure many illegitimates will attest to failing rubbers. I abandoned the concept, however, eventually came back and made a confessional video when I found the error of my ways.

What I found was that you do not pre-pop the rubber insert. Just drill the hole,

shove it in,

and then just bolt it in,


I found that it worked equally well in solid timber… drill the hole,

slip in the rubber,

and screwed it,

though still with the absence of scientific stress tests.

After some comments made to the video, I promoted the 6mm rivnuts from 3mm MDF to 6mm with success,

Thanks rc

Just to prove I don’t always talk shit… here’s a jig I was forced to make out of timber,

as it blew out when I needed “threads” in MDF,

Please don’t rush out and buy yourself a set of Rivnuts and setters… Not until I buy a few shares in the company.

-- If your first cut is too short... Take the second cut from the longer end... LBD



9 comments so far

View stripit's profile

stripit

116 posts in 2929 days


#1 posted 10-13-2020 01:35 PM

Great presention, as always. I enjoy your posts, they make me LOL in the morning. Keep it up.

-- Joel, People ask what I make. I tell them I make sawdust, and now and then a nice box or frame,or clock, or lamp pops out.

View Dutchy's profile

Dutchy

3830 posts in 3054 days


#2 posted 10-13-2020 04:54 PM

Thanks for sharing. Would it work with solid wood?

-- https://dutchypatterns.com/

View LittleBlackDuck's profile

LittleBlackDuck

5822 posts in 1706 days


#3 posted 10-13-2020 09:18 PM



Thanks for sharing. Would it work with solid wood?

- Dutchy


Haven’t tried too many experiments as I would normall use my Wood Whisperer taps in solids.

The rubber inserts will work, however, I wouldn’t depend on too much pull strength… To hang something vertically would be my limit as long as there not too much twisting forward and down force.

Primarily I use it in thin metal… the MDF was an after thought when I couldn’t tap it (or use thread insert it with satisfactort results).

-- If your first cut is too short... Take the second cut from the longer end... LBD

View robscastle's profile (online now)

robscastle

7446 posts in 3090 days


#4 posted 10-15-2020 12:22 AM

I gave up looking for your Up market Lazy Susan or whatever splintergroup was gobbing off about.

Thanks for your input too really appreciate fooling about all day on wild goose/duck chases.
Anyway enough of the bellyaching.

I have decide to focus more on your nuts.

I am not sure if I told you about putting nutserts into 3rd hands to get rid of all the excessive bits involved with their adjustment.

Let me know if I didn’t and I might go look for them to show you.

-- Regards Rob

View LittleBlackDuck's profile

LittleBlackDuck

5822 posts in 1706 days


#5 posted 10-15-2020 02:00 AM

You didn’t… or you can’t remember that I can’t remember… or I can’t remember what I forgot.

As for my nuts… I’m quite happy to focus on them.

-- If your first cut is too short... Take the second cut from the longer end... LBD

View robscastle's profile (online now)

robscastle

7446 posts in 3090 days


#6 posted 10-15-2020 10:59 AM

OMG well anyway some Good Hand clamps ( not 3rd hand incorrectly reported earlier) are able to be modified so all the additional washers nuts and other annoying bit can be removed on some (depending on their design) and a suitable size nutsert fitted in their place.

Its only the very small ones that have a folded steel arm.

-- Regards Rob

View robscastle's profile (online now)

robscastle

7446 posts in 3090 days


#7 posted 10-15-2020 08:42 PM

You will lose a small amount of lateral adjustment but nothing vibrates loose any more.

-- Regards Rob

View LittleBlackDuck's profile

LittleBlackDuck

5822 posts in 1706 days


#8 posted 10-15-2020 11:32 PM

Sorry rc but I’m now totally lost… must be all those slaps on the back of the head from SWMBO for daring to say that she is banned from LJs in pottzy’s _corona crazy threads…
I won’t say it the vino as that’s what I take to cure the slaps.

As for the,

I use the Rockler

less thinking required. Ya gotta ‘member (Country party), I’m over 71.

-- If your first cut is too short... Take the second cut from the longer end... LBD

View robscastle's profile (online now)

robscastle

7446 posts in 3090 days


#9 posted 10-16-2020 10:01 PM

Yeah I need my beer here too.

I still like looking at your nuts though !

Trust you to have the upmarket varieties!

As for the pottzy’s _corona crazy threads…
I agree.

Maybe he is trying to outdo Stumpies

-- Regards Rob

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