Threaded inserts in MDF

TheHighFlyingBirds

Distinguished Member
I'm looking at possibly building some speaker stands to sit my shiny (still boxed) kef R3's on. My design is basically a mdf top plate allowing speakers to be bolted to the stand, held up by 4 oak spindles (41mm x 41mm), which would then be connected to an mdf base (thinking 3 layers of 18mm mdf). Spindles to be connected via a screw and dowel.

Now as the stands will need spikes, whats the best way of fitting some so they are well secured? I can think of two options:

A- put a threaded insert directly into the mdf bottom face (insert type to be determined, recommendations welcomed).

B- drill hole and glue in a big enough (hard/soft wood) dowel (say >20mm) then fit the insert into the dowel (again recommendations on type welcomed).

Will A be strong enough so the insert doesn't get ripped out? Is B overkill? Or should I just buy the atacama nexxus stand and then decide on whether to buy the large top plate option or make my own (both options could allow for bolting option if drill them).

@Ugg10 you seem to be doing quite a bit of diy hifi so interested if you done similar before.

Cheers
 

Ugg10

Distinguished Member
Sounds like a nice project, am considering something similar but with scaffolding poles for the corners (around 50mm diameter), if I make the gap over 30cm then you can also use them for LP storage, I think the new Linton stands are like this.

As the spike is on the underside I would use top hat style inserts (also called T nuts) rather than the straight cylinder ones, you won’t see the top hat as it will be underneath and will stop any push through from the weight of the speaker. This will also give a decent surface for any locking nut to act on rather than the wood. If you can design with thick enough MDF then these can be in blind holes but still allo a few mm adjustment on the spikes but not seen from the top. There are a few styles some more “functional” than others, I have just used stainless rivnuts (just as an insert not compressed up) also in the past with epoxy glue as the actual torque will be very little.

Also worth noting that it is not very expensive to get the MDF pre cut to size with rounded corner or cut outs if you search for it, just in case you don’t have cutting equipment.

Something like these but have a search around.

Rivnuts


More functional

 

TheHighFlyingBirds

Distinguished Member
Thanks @Ugg10. I had looked at them T nuts, and was trying to work out if they would pull out. Would you put a spot of glue on before inserting them? Good point about the surface for the locking nut to seat against.

The base would be 54mm thick by layering 3 18mm pieces so plenty of meat above so would allow any long threaded spikes to be hidden.

Was going to do cuts etc at my dads if I go ahead with the project as he has the required tools (bench saw, pillar drill etc). Just will be a bit slower as couldn't do it all in one go. Although if I get the mdf cut to size in advance then could glue up the base in advance at home, before drilling at my dads.

Next issue to think about is finish. Was thinking gloss spray on top and bottom plates to match the black gloss of the kefs. Then maybe matte black pillars / spindles. Had considered a kevlar vinyl wrap on the base, but think getting neat edges / corners would be more difficult than a paint finish.
 

Ugg10

Distinguished Member
The inserts in the base should not pull out as the weight is trying to push then into the wood not pulling them out.

With MDF painting is all in the preparation, sealing the wood, lots of filler and primer especially on the cut ends, lots of sanding and then final coats and lacquer.
 

TheHighFlyingBirds

Distinguished Member
Yep, agree prep is key, just need to make sure I don't rush just to get them finished so I can get my speakers set up. My design is attached.

Cant fit in any vinyl in current design, but you have me thinking if I should rearrange the pillars so there is a gap in the centre allowing for storage, as I am running out of vinyl storage space. It will have the added bonus of adding mass to the stand but not sure it'll look as good, especially with a load of vinyl in detracting from (hopefully) sharp clean lines. Will try that arrangement in sketchup if I get 5 mins spare to see how it'll look, although space would be limited to circa 78-98mm, so maybe upto 15 LPs max.

Think I'm edging to custom build, as love build projects, will be tailor made for the kefs and could come in for less money than buying.
 

Attachments

  • speaker stand pdf.pdf
    104.5 KB · Views: 24

IronGiant

Moderator
All those options are designed to span the mdf and will work fine. I get the impression the OP wanted an option that would fit from one side?

more like this?

 

IronGiant

Moderator
Such things are used by subwoofer manufacturers where the subs weigh 10s of kilos, so I think you will be fine.
 

TheHighFlyingBirds

Distinguished Member
All those options are designed to span the mdf and will work fine. I get the impression the OP wanted an option that would fit from one side?

more like this?

Yep looking for something to insert into the bottom (ooh er) face upwards, which will allow the spike to screw into. I assume the inserts @Ugg10 mentioned would meet this requirement. When you say they are designed to span the mdf, what do you mean?

The ones you have linked to, I was looking at along with the solid threaded inserts. Just after ideas which work well from peoples experience.
 

IronGiant

Moderator
I think I might have misunderstood him. T-nuts are often used to mount speakers in their cabinets in which case they are placed on the inside and I assumed he was suggesting the same. On re-reading I'm not sure, and perhaps he did mean to apply them from the outside.
 

TheHighFlyingBirds

Distinguished Member
Looking at the type d inserts that you linked, as they will likely be easier to install I think. For the t nuts, all videos install them using a bolt and nut to pull the nut into the wood from the rear, which would require the nut to be installed before I glue the 3 layers together.

Now updated the design @Ugg10 allowing vinyls to be stored in the middle. Will only have 78mm gap, so not huge amount of storage.

With regards to painting, was thinking using a matte black spray with a clear gloss finish. Good or bad idea?
 

Attachments

  • speaker stand v2.pdf
    73.5 KB · Views: 11

Ugg10

Distinguished Member
I would scratch the idea of the LP storage, only really works with wider designs. Like these.

linton-image-1_2_1.jpg
 

TheHighFlyingBirds

Distinguished Member
I would scratch the idea of the LP storage, only really works with wider designs. Like these.

linton-image-1_2_1.jpg
I agree, besides I think I prefer my first design anyway, as its not as boxy looking. Just got to finalise my design measurements and then can start ordering parts. Think I'll start a build thread and hope it can get near the quality of yours.
 

TheHighFlyingBirds

Distinguished Member
Quick update, got some of them type d threaded inserts. Had a trial of them before I use them in anger and bloody hell they don't half grip. They'll be perfect for the spikes.
 

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