# Pilot Holes in MDF



## patlaw (Jan 4, 2010)

I am going to mount some casters on a 19" equipment rack that is made of MDF. The mounting holes in the casters are big enough for #12 or #14 screws, but I'm going to use #10 sheet metal screws. What size pilot hole do I need to drill in MDF for these #10 screws? Is there a chart?

2" Rigid Non-Marking Rubber Caster


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## RainMan 2.0 (May 6, 2014)

I have 3/32" or 1/8" in my head from memory , but I would just do a test on a spare piece of mdf and see how they take


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## Cherryville Chuck (Sep 28, 2010)

Rick makes a good point. Charts are for hardwood or softwood and mdf is neither. https://www.google.ca/url?sa=i&rct=...avmg45pG0JozMAZ3P1iBtA7w&ust=1461644642242051


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## LazurusLong (Jan 20, 2015)

I usually through bolt casters. It's a bit more work, and you have to get the right length bolts, but you never really have to worry about the screws tearing out.


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## Stick486 (Jan 4, 2013)

I'm w/ Jesse...
through bolt before the screws spawl/tear out/ break the MDF...


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## Cherryville Chuck (Sep 28, 2010)

I've had the same problem and when one castor falls off it can get exciting depending on which machine is on the dolly.


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## patlaw (Jan 4, 2010)

LazurusLong said:


> I usually through bolt casters. It's a bit more work, and you have to get the right length bolts, but you never really have to worry about the screws tearing out.


Yes, I considered this option, and I may go with it, but the rack will be on a wood floor with very little movement. The total weight will be less than 100 pounds. There will be very little lateral pressure on the wheels, reducing the likelihood of tearout, but there is no doubt that through bolting them would be the best option.


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## PhilBa (Sep 25, 2014)

The best way to determine the pilot hole for a screw is get a drill size that creates a hole for the shank of the screw. You can tell by holding both up to a brightly lit background with the drill bit in back of the screw. If you can see any of the drill bit, it's too big. 

Also, you can harden MDF holes by using superglue/cyanoacrylate.

But, I'm with the guys on bolts. #10 bolts with washers will be 10X stronger with the MDF in compression and last a lot longer than any screws. The failure mode to worry about is not one time tearout but rather repeated stress that weakens the screws hold. No matter how tight they seem when you put them in, they will eventually work loose as MDF just doesn't have the shear strength.


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## dalboy (Jun 12, 2012)

I am also with the idea of using bolts, putting the bolt in from the top down through the unit and into the base and then through the caster


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## Garyk (Dec 29, 2011)

Agree with the bolts, could save a squished toe.....


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## wags999 (Nov 6, 2013)

Other option would be glue a sq piece of hardwood to the bottom where each caster will be attached. Then screw into the hardwood.


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## Arcola60 (Jul 4, 2009)

Bolt it and be done with it. I bolt all of my casters, toggle clamps, etc., anything with stress. That takes away my stress. I will also epoxy "T" nuts in MDF. I had them keep sliding out on fixtures that are adjustable, not anymore! I tried lag bolts with predrilled pilot holes. Until I hit a void and it spun on me. It was the last one, always. No more worries for me anymore. It took a while for me to get the message, but I finally got It!

My wife says that I am the king of overkill, as she smiles at my progress. I took it as a compliment.

Ellery Becnel


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## RainMan 2.0 (May 6, 2014)

I like the bolt right threw idea the best . 

I just remembered , I used carriage bolts when I installed my casters . Never had any issues


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## Stick486 (Jan 4, 2013)

TheCableGuy said:


> I like the bolt right threw idea the best .
> 
> I just remembered , I used carriage bolts when I installed my casters . *Never had any issues*


yet...
give it time...


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## patlaw (Jan 4, 2010)

Ok, so I went to Fastenal today and bought 50 12-24 screws, 100 nuts, and 100 washers. It was $25. Those casters had better not fall off!


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## Nickp (Dec 4, 2012)

Glad you're going through bolts...those wheels are set off center and even if you didnt roll it there is always stress on the screws.


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## patlaw (Jan 4, 2010)

And just now I learned that the screw holes are for 1/4"-20, which I already had in stock.


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## Nickp (Dec 4, 2012)

patlaw said:


> And just now I learned that the screw holes are for 1/4"-20, which I already had in stock.


So Murphy is visiting your place tonite...?

Teehee...spares are always good...

Something I've been doing for a while...when I need wheels I buy a 1000lb'er dolly, strip the wheels off, use the nuts and bolts in whatever I'm putting them under and it's cheaper than buying all the parts. Then I either use the wood or chuck it...


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## Stick486 (Jan 4, 2013)

Nickp said:


> So Murphy is visiting your place tonite...?
> 
> Teehee...spares are always good...
> 
> Something I've been doing for a while...when I need wheels I buy a 1000lb'er dolly, strip the wheels off, use the nuts and bolts in whatever I'm putting them under and it's cheaper than buying all the parts. Then I either use the wood or chuck it...


same deal here...


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## cocobolo1 (Dec 31, 2015)

patlaw said:


> And just now I learned that the screw holes are for 1/4"-20, which I already had in stock.


Naturally. Isn't that the way it always works? :smile:


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## patlaw (Jan 4, 2010)

To add to the store of useless information, I went back to Fastenal and got 1/4-20 screws, nuts, and matching washers. The screws should have been 1/4" longer as I was not able to use a washer. The whole shebang was half the price of the 12-24 screws, nuts, and washers. Go figure.

These wheels from Home Depot are excellent. The equipment rack rolls around quite easily.


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