Just about to build my UAII...but read about MDF splitting?

[ras2a]

Just been reading horror stories on the board about splitting problems when going into the edge of MDF.  Obviously with the Ultimate Arcade II, it's a bit hard to avoid as the entire thing is made from MDF! and many of the panels require screwing into the 'edge' of other panels  I assume that pilot holes, the same width as the screw shank being used should do the trick?

I suppose it's good to 'trial' anything on scrap pieces first too

Thanks a lot

Craig

[Santoro]

It will not work screwing into the edge of MDF.  Period.    Don't do it. Really.

Seriously though, you need to use ledgers.  Basically ledgers are pine supports glued & screwed into the MDF, then you screw into those instead. See any construction photo on the board here and you will see ledgers.

[edit:  here's mine]

[ras2a]

Ok I do see what you're saying, but why on earth would the creators of the UAII not point this out on the plans...surely this would mean they would have loads of disgruntled folk who had bought the plans and put it together 'exactly' as outlined only to be annoyed when they encoutered 'splitting' - because the plans tell you to screw into the edge of the MDF.  I noticed there on your cab (very nice btw) that you have 'ledgers' but looking at the 'top' panel on your cab I can't see how it's fixed to the side-panels ?  I've marked on your photo where the screws are supposed to go in (No: 1/2 - according to the plans).  No.3 - This is where I assume you are talking about screwing using the ledgers...



You must forgive me ignorance in woodworking

thanks a lot for your help - I really appreciate it

Craig

[Santoro]

Not sure what they were thinking.  Hopefully someone who has built one will speak up.

I speak from experience - I tried using MDF for ledger when I first started out and it had zero holding power when I managed to get the screw in without splitting.

[ras2a]

Not sure what they were thinking.  Hopefully someone who has built one will speak up.

I speak from experience - I tried using MDF for ledger when I first started out and it had zero holding power when I managed to get the screw in without splitting.

Oh sorry...I just replied - I may sound a little dense but using your photo can you describe precisely where I screw into for this to work...?..again I can't visualise how that panel at the very top (ie the top adjoining panel in between 1 & 2) is actuall fixed to each of the side panels...?  Have you used long screws to screw up through the underside of those ledgers into the underside of the top panel?

edit: Ok now I'm getting confused.  Just been speaking to my brother and he says he's experienced the splitting problems in the past with building things out of MDF before, but he maintains you can do this provided you do it right.  He says that using cabinet clamps to hold pieces together is required and then drilling through the surface of one into the edge of the other thereby creating pilot holes.  Now Im actually using 5/8" MDF and he has had a look at the UAII plans, he says the guage of screw specified in the instructions is what may be causing splitting for some folk.  He has bought some 3mm guage screws for my cab and says they will do the job no problem using my 16mm (5/8") MDF....and we wont get any splits.  He also said that the screws must not be regular wood screws (ie tapered) but that they must be of fixed shank guage so as not to act as a wedge (apparently this drives the fibers apart).  He also swears by using connector blocks on the inside to hold panels together...now to me these look insufficient and he concurs but assures me that they work just fine, as he has built numerous cabinets, wardrobes etc of different sizes! in the past and used them for strengthening...with no ill side-effects!

Craig

[Santoro]

On the top I drilled counter-sunk holes and screwed down into the ledger.  Then I used wood putty to cover the holes and sanded.

[ras2a]

On the top I drilled counter-sunk holes and screwed down into the ledger.  Then I used wood putty to cover the holes and sanded.

Aha - I'm with you.  Ok read my above 'edit' in my previous post...my brother reckons you can screw into the edge of MDF with no ill effect!

cheers Santoro

Craig

[VMJ Team]

The splitting of the wood occurs under the following conditions:

1) Inadequate pilot holes or lack of pilot holes:
Pilot hole size and depth must correspond with the size wood screw being used.  Also, the material used has an affect on the pilot hole size (hard/soft wood). Refer to any sizing chart for more info:

http://www.bitsnbores.com/html/screw_chart.html

2) Oversized wood screws.  On a 5/8" thick piece of wood, it is not recommended to use screw sizes larger than a #10 wood screw.

One thing to keep in mind....whether you use the ledger method described in this thread or screw the panels together using the method outlined in the UAII plans...without adequate pilot holes, you'll end up splitting the wood in both cases.

[ras2a]

The splitting of the wood occurs under the following conditions:

1) Inadequate pilot holes or lack of pilot holes:
Pilot hole size and depth must correspond with the size wood screw being used.  Also, the material used has an affect on the pilot hole size (hard/soft wood). Refer to any sizing chart for more info:

http://www.bitsnbores.com/html/screw_chart.html

2) Oversized wood screws.  On a 5/8" thick piece of wood, it is not recommended to use screw sizes larger than a #10 wood screw.

One thing to keep in mind....whether you use the ledger method described in this thread or screw the panels together using the method outlined in the UAII plans...without adequate pilot holes, you'll end up splitting the wood in both cases.

Hiya CyberPunk

Yeah this is what my brother was telling me (screw guages etc - its all  double-dutch to me)...thanks for the info.  I'm not sure yet which method I'll use.  Methinks I'll test on a couple of scrap pieces first

Cheers guys

Craig

[Santoro]

I dunno, you brother sounds like he knows what he is taking about.  Try it on scrap and see if you have better results than the rest of us.  

[ras2a]

I dunno, you brother sounds like he knows what he is taking about.  Try it on scrap and see if you have better results than the rest of us.  

Certainly will, and thanks again for all your help

Craig

[pointdablame]

Your brother is both right and wrong... at least in my experiences.  It is totally possible to use the correct pilot holes and screw gauges and then drill into the side of wood.  However, this is not possible (again, in my experiences) with MDF.  If you're using hardwoods, no problem at all.  MDF is a whole other story though.

Your brother sounds knowledgeable, try it out on some scraps when he's around.  He should see immediately that there is very little holding power when screwing into the side of the MDF.

Trust me, put up framing pieces and drill into those.  First, drill AND glue the supports onto the MDF sides, then attach the other pieces into the framing, not the MDF.  You'll be much happier, less aggravated, and have a MUCH MUCH sturdier cabinet.

[sjgrover]

I wouldn't try it with 5/8" MDF, but when you use 3/4" it is possible to screw into the edge.  Countersinking is a given but you also need to use drywall screws (they have coarser threads with a thin shank that holds without stripping in the MDF) and put one in every 3 inches but no closer than 1 1/2 inches from the end of the board.  

[bwest]

I have build alot of furniture and cabinets out of MDF and screw into the edge of MDF all the time.  What everyone has said about pilot holes and screws sizes is definately a must.  

However, screws alone have little holding strength in MDF.  Screws are really only enough to hold the MDF in place while the glue dries.  In addition, I cut dados and this all but stopped all splitting and improved the joints tremendously.  However, you need a router, 3/4" straight bit, and a straight edge guide to do it.

Without the above, the ledger is the easiest to do.

[JAMMA Guy]

I built a cabinet last year out of AC plywood ... this year I used MDF instead.  It's every bit as strong as the AC with confirmat screws (no glue or dados required).  A little Titebond doesn't hurt but it's fine without.

You don't need huge pine ledgers either ... I made my ledgers out of 3/4" x 3/4" MDF and I've already had my 80lb+ WG D9200 bolted into the cabinet and I didn't notice it falling apart  ( ... all that does is add extra weight to the cabinet and take up space .. not that there's anything wrong with that   ).

Confirmat Screws

or

Hi-Lo Screws

(5mm x 40mm --> 5/8" or 7mm x 50mm 3/4")

Actually I've used the 5mm starter kit for 3/4" ... worked just fine if you need to save yourself a little money ( ... one kit does an entire cabinet)

Save yourself some trouble and buy the correct screws when working with MDF, Melamine, or Particle Board ... especially when screwing into the so called "end grain" ... I guess MDF has end grain ... hehe  

Regular wood screws work fine everywhere else though.

Also ... these screws come with a special step pilot bit ... perfect pilot holes everytime.

The reason the MDF splits most of the time is that most wood screws are tapered which means your pilot hole has to be just right for the upper part of the screw or it will split

The wood screw itself is usually tapered too ... so only a fraction of it is actually holding the joint togehter.  That's the cause for the weak holding power.

...  the main cause of splitting though is normally the tapered wood screw head itself.  If you tighten the wood screw to much the tapered head usually ends up busting out the pilot hole (usually that last turn of the screw driver that ends up ruining your day .... lol)

With the right knowledge and tools you can accomplish much (btw ... stop by the MAMEROOM forum sometime ... what's not covered in the plans I'll happily help you with (that's why the forum is there) ... I got a thread that almost walks you step by step through the building process ... I've built two UAII cabinets so I can help you through every step of the plans should you encounter a problem   ).

[Postalp]

I am one of those few that edge screwed MDF. But it worked for for 2 reasons...

#1) The MDF I got is 3/4" and VERY high density stuff (Melamine coated as well.

#2) Pre-Drill Pilot holes.

[ras2a]

Well what can I say, I wasn't expecting this many replies to my thread.  You guys are absolutely fantastic - seriously!

I really do appreciate all your help.  What an ace place these forums are

Thanks a tonne guys

Craig

[bwest]

Jammaguy,

Gonna try those screws listed.  I am very curious how well they work.  If they work for me like they have for you, I will be in hog heaven.

[ras2a]

After all my indecision I decided (along with my brother) to opt for the extra strength in the form of spruce ledgers.  I managed to start constructing the bottom section oh my UAII today...hope to get more done tomorrow.  Used 'Spax' screws (think these are german - our UK folk will have probably heard of these)...so far so good. Some pics below:









No that's not a floating car in the background!...it belong's to one of the bosses, we have our own mechanic in house and his car is in for service.  And yes, No coin door/hole...nah it was just more expense and something that I don't feel the need for (arrggh SACRILEGE!

Craig

[Tahnok]

I just built my entire cab out of standard 3/4" MDF screwed into the edge. If you drill pilot holes then it is no big deal. I may end up throwing some ledgers in there just to be sure though.

[warreng]

With the right knowledge and tools you can accomplish much (btw ... stop by the MAMEROOM forum sometime ... what's not covered in the plans I'll happily help you with (that's why the forum is there) ... I got a thread that almost walks you step by step through the building process ... I've built two UAII cabinets so I can help you through every step of the plans should you encounter a problem   ).

Could you possibly post a link to this thread? I have been over to the MAMEROOM forums but can't seem to find it.

Thanks,
warreng