Power Rack Platform

[gabeinphx]

If I wanted to build a platform strictly for bolting down, assuming I could get away with a 3/4 MDF platform? Only purpose for platform is to keep legs from shifting left or right. I have researched and everyone sandwitches 3 boards togther to make a true weightlifting platform . Not necessary for me as I already have rubber matts and rubber coated weights. Not sure what other benefits I would get. Also would start getting into a height issue as 92" for the rack I purchased is already close to the ceiling, do not want to add too much on the height.

Are there better materials to use than MDF. Only thought about that as it is smooth and fairly easy to work with as far as rounding off the corners.

[maltralson]

If I wanted to build a platform strictly for bolting down, assuming I could get away with a 3/4 MDF platform? Only purpose for platform is to keep legs from shifting left or right. I have researched and everyone sandwitches 3 boards togther to make a true weightlifting platform . Not necessary for me as I already have rubber matts and rubber coated weights. Not sure what other benefits I would get. Also would start getting into a height issue as 92" for the rack I purchased is already close to the ceiling, do not want to add too much on the height.

Are there better materials to use than MDF. Only thought about that as it is smooth and fairly easy to work with as far as rounding off the corners.

I would probably just use a regular 3/4 inch plywood, I wouldn't think mdf would hold up well to any moisture coming from the floor?

[gabeinphx]

Moisture is not an issue as this is indoors over hardwood floors. But 3/4 should be OK right?

[irongrandpa]

Use 3/4 plywood, MDF is great for some uses, but plywood is the better choice for a platform.

[Mech6]

The dust from MDF is toxic. I wouldn't want to start dropping plates on that.

[sowilson]

Don't use OSB or MDF they're not nearly as strong as plywood, use void free plywood. You'll probably want BC or AC. 3-4 layers of 3/4" plywood laid in a crisscross pattern that is glued and screwed makes for a very strong top. One layer of 3/4" 4x8' plywood might be ok but it would really only provide tip protection in the long direction (8') and almost none in the other (4'). Even then the plywood may fail with a top-heavy rack. If at all possible use two crisscrossing layers that are glued and screwed in either a 6'x8' or 8'x'8' configuration. That should provide enough leverage to resist a top-heavy rack as well as being fairly strong. Why don't you just bolt your rack to the hardwood floor and then when you decide to leave drill out the lag bolt holes, install a wood plug, saw the plug flush, sand, and finish with a bit of poly. Done correctly it will look ok.

[FNG37]

Don't use OSB or MDF they're not nearly as strong as plywood, use void free plywood. You'll probably want BC or AC. 3-4 layers of 3/4" plywood laid in a crisscross pattern that is glued and screwed makes for a very strong top. One layer of 3/4" 4x8' plywood might be ok but it would really only provide tip protection in the long direction (8') and almost none in the other (4'). Even then the plywood may fail with a top-heavy rack. If at all possible use two crisscrossing layers that are glued and screwed in either a 6'x8' or 8'x'8' configuration. That should provide enough leverage to resist a top-heavy rack as well as being fairly strong. Why don't you just bolt your rack to the hardwood floor and then when you decide to leave drill out the lag bolt holes, install a wood plug, saw the plug flush, sand, and finish with a bit of poly. Done correctly it will look ok.

No glue.

Unless you plan to die in that house and never change or want another platform. Trying to manhandle an 8'x8' bomb blast door of 4-5 pieces of 3/4" to cut down into manageable sizes sucks. Just screw it.

[Cleveland33]

Don't use OSB or MDF they're not nearly as strong as plywood, use void free plywood. You'll probably want BC or AC. 3-4 layers of 3/4" plywood laid in a crisscross pattern that is glued and screwed makes for a very strong top. One layer of 3/4" 4x8' plywood might be ok but it would really only provide tip protection in the long direction (8') and almost none in the other (4'). Even then the plywood may fail with a top-heavy rack. If at all possible use two crisscrossing layers that are glued and screwed in either a 6'x8' or 8'x'8' configuration. That should provide enough leverage to resist a top-heavy rack as well as being fairly strong. Why don't you just bolt your rack to the hardwood floor and then when you decide to leave drill out the lag bolt holes, install a wood plug, saw the plug flush, sand, and finish with a bit of poly. Done correctly it will look ok.

No glue.

Unless you plan to die in that house and never change or want another platform. Trying to manhandle an 8'x8' bomb blast door of 4-5 pieces of 3/4" to cut down into manageable sizes sucks. Just screw it.

This is getting a bit complicated - he's not building a platform, he's just wants something to bolt his rack to.

In this case, a single 4x8 sheet of 3/4" plywood will be sufficient assuming is rack is 48" wide or less.

[Mech6]

No glue.

Unless you plan to die in that house and never change or want another platform. Trying to manhandle an 8'x8' bomb blast door of 4-5 pieces of 3/4" to cut down into manageable sizes sucks. Just screw it.

agree

[sowilson]

This is getting a bit complicated - he's not building a platform, he's just wants something to bolt his rack to.

In this case, a single 4x8 sheet of 3/4" plywood will be sufficient assuming is rack is 48" wide or less.

Let's say your rack is 43" wide and you bolt it to a 48" wide piece of plywood. That gives you 2.5" of overlap on either side. That will do nothing to prevent a 400lb rack from tipping in that direction. You really would want a foot of overhang on either side, so for a 4'x4' rack (or close) then you would want a minimum of a 6'x6' platform. Which would require two sheets of 4'x8' plywood. To make a decent 6'x6' or 8'x8' base you would want a minimum of two sheets that are mechanically (and preferably glued) coupled. If you had a small rack you could probably get by with a single piece of 3/4" 5'x5' Baltic birch plywood.

As for gluing and screwing being overkill, it would be if you plan on moving your platform. I would look at it as a consumable and just cut it up with a sawsall when I'm done with it. If you want to rely on just mechanical connectors (screws) then make sure you have sufficient density (say 1' OC) going through all layers. I've seen what happens when you go to move heavy machinery and haven't built the proper pallet or skid for it - not pretty. Sometimes bomb doors are good. Racks are heavy and can be tippy. If a rack needs to be bolted down (i.e. it's tippy) then I would make sure whatever I bolt it to is up to the task - not just convenient. Leverage is your friend

[Cleveland33]

Let's say your rack is 43" wide and you bolt it to a 48" wide piece of plywood. That gives you 2.5" of overlap on either side. That will do nothing to prevent a 400lb rack from tipping in that direction. You really would want a foot of overhang on either side, so for a 4'x4' rack (or close) then you would want a minimum of a 6'x6' platform. Which would require two sheets of 4'x8' plywood. To make a decent 6'x6' or 8'x8' base you would want a minimum of two sheets that are mechanically (and preferably glued) coupled. If you had a small rack you could probably get by with a single piece of 3/4" 5'x5' Baltic birch plywood.

As for gluing and screwing being overkill, it would be if you plan on moving your platform. I would look at it as a consumable and just cut it up with a sawsall when I'm done with it. If you want to rely on just mechanical connectors (screws) then make sure you have sufficient density (say 1' OC) going through all layers. I've seen what happens when you go to move heavy machinery and haven't built the proper pallet or skid for it - not pretty. Sometimes bomb doors are good. Racks are heavy and can be tippy. If a rack needs to be bolted down (i.e. it's tippy) then I would make sure whatever I bolt it to is up to the task - not just convenient. Leverage is your friend

This isn't to prevent it from tipping, it's to prevent the legs from splaying/shifting. The load will prevent it from tipping side to side.

[sowilson]

This isn't to prevent it from tipping, it's to prevent the legs from splaying/shifting. The load will prevent it from tipping side to side.

Do you know the rack that the OP is wanting to bolt down? Properly built it shouldn't splay or shift. I could see it wanting to walk if the floor isn't flat and level or the rack bottom isn't flat. If the load is dropped from height you could have a tipping issue (depends on the dimensions of the rack), or if you have a fairly small rack and decide to do pull ups from the outside.

[Cleveland33]

Do you know the rack that the OP is wanting to bolt down? Properly built it shouldn't splay or shift. I could see it wanting to walk if the floor isn't flat and level or the rack bottom isn't flat. If the load is dropped from height you could have a tipping issue (depends on the dimensions of the rack), or if you have a fairly small rack and decide to do pull ups from the outside.

I'm guessing it's the HD Titan since he said he ordered one in that thread. It's similar to the R-3 bolt together, which needs to be bolted down to prevent splaying (which I am betting what he means by shifting) because there is no lower rear crossmember.

Bolted down or not, I can't imagine a rack 43" wide or wider tipping side to side, even under weight. Tipping back, sure if it's legs don't extend back. But if it's bolted down to a platform you're standing on, it's a non-issue.

[Mech6]

This isn't to prevent it from tipping, it's to prevent the legs from splaying/shifting. The load will prevent it from tipping side to side.

This. 10000%. Bolting it is mostly to keep the damn legs at proper distance.

[Mech6]

Do you know the rack that the OP is wanting to bolt down? Properly built it shouldn't splay or shift. I could see it wanting to walk if the floor isn't flat and level or the rack bottom isn't flat. If the load is dropped from height you could have a tipping issue (depends on the dimensions of the rack), or if you have a fairly small rack and decide to do pull ups from the outside.

Also true, but most racks with braces only at the top (rogue...) and nothing at bottom are going to splay.

[GreatOldOne]

No glue.

Unless you plan to die in that house and never change or want another platform. Trying to manhandle an 8'x8' bomb blast door of 4-5 pieces of 3/4" to cut down into manageable sizes sucks. Just screw it.

I made this mistake once...and you tear up the plywood with a wrecking bar to get it undone when they're glued together (unless there's a secret I didn't know about).

Made a platform again without the glue and it was easy to breakdown and transport to a new house.

[gabeinphx]

Thanks for all who posted suggestions, plywood it is, did not realize MDF was toxic, but that is why I asked the question to see if I was going in the wrong direction. Tipping is not a concern as I dont plan on making the rack top heavy. The rack itself is 200lbs and will load the weight storage they provide (installed low on the rack) with weights that are not used. If weights are used they will be for squatting and I will be on the platform as well. If I had more space a lifting platform would be nice, but working with an 11x11 room that is used for office/gym including my wife's elliptical.

[RandyMcdonald]

No glue.

Unless you plan to die in that house and never change or want another platform. Trying to manhandle an 8'x8' bomb blast door of 4-5 pieces of 3/4" to cut down into manageable sizes sucks. Just screw it.

Good point. Although it would be nice to have a full sized platform, those things are unwieldy and heavy! Guys never think long term when gluing them together. Then later have to cut into small pieces to get them out of the room/house.

[gabeinphx]

I did have one other question. Is it ok to use a screw to secure rack to plywood, or does it actually have to be bolted from the bottom. Only reason I ask is I am only using one sheet and would have to countersink the bolt so the hardwood is not scratched, leaving less than 1/2 of plywood holding the rack in place. Thinking I could get more depth with a 3/4 screw (should not go through due to thickness of rack metal I will also be going through.

[JamesMontana]

My 2 cents on the subject:

I had the HD titan power rack bolted to a 3/4" plywood on top of two 1/2" OSB sheets to prevent from leg splaying and to match the oly platform in front of it. Racking anything over mid 3 plates would tip the opposite end of the platform a bit, with me still on it. I feared that if I racked any harder, the rack could actually fall.
So I agree that layer(s) of 6x8' plywood will not sufficiently prevent a rack from tipping.

[gabeinphx]

My 2 cents on the subject:

I had the HD titan power rack bolted to a 3/4" plywood on top of two 1/2" OSB sheets to prevent from leg splaying and to match the oly platform in front of it. Racking anything over mid 3 plates would tip the opposite end of the platform a bit, with me still on it. I feared that if I racked any harder, the rack could actually fall.
So I agree that layer(s) of 6x8' plywood will not sufficiently prevent a rack from tipping.

Not sure I undersdand what direction was your rack tipping in? I don't see how this rack bolted to a 4x8 would be any less safe than a rack with a crossmember on the rear side of the rack. Not planning on installing on the very end of the plywood, will be leaving 6-8" overhand on the rear side and the rest will be on the front end. This shoud provide very similar stability as this rack from rogue, which does not even have cossmember on the bottom part of the rack.

http://www.roguefitness.com/rml-390f...ster-lite-rack

[sowilson]

I did have one other question. Is it ok to use a screw to secure rack to plywood, or does it actually have to be bolted from the bottom. Only reason I ask is I am only using one sheet and would have to countersink the bolt so the hardwood is not scratched, leaving less than 1/2 of plywood holding the rack in place. Thinking I could get more depth with a 3/4 screw (should not go through due to thickness of rack metal I will also be going through.

I'm glad you thought of this. Since you don't want to scratch the wood floor you're putting your gym on you'll need to countersink pretty much any connector you use. You are right to be concerned about having a countersunk nut and washer being pulled through since only 1/4"-5/16" or plywood would be anchoring it. You could use a threaded insert or a t-nut but I'm not sure if they would be strong enough either. I wouldn't trust a wood screw. Layering 2 sheets of plywood and bolting through both sheets would be much, much better. If you insist on using a single sheet of 3/4" plywood I would have a machine shop cut a couple of backing plates (3/16" or 1/4") and weld on some flanged weld nuts. A plate 2"x3" should suffice. Then you would use a router and route out a recess for the plate and drill a hole for the weld nut. Your rack wouldn't have a chance of pulling that connector out.

[gabeinphx]

I'm glad you thought of this. Since you don't want to scratch the wood floor you're putting your gym on you'll need to countersink pretty much any connector you use. You are right to be concerned about having a countersunk nut and washer being pulled through since only 1/4"-5/16" or plywood would be anchoring it. You could use a threaded insert or a t-nut but I'm not sure if they would be strong enough either. I wouldn't trust a wood screw. Layering 2 sheets of plywood and bolting through both sheets would be much, much better. If you insist on using a single sheet of 3/4" plywood I would have a machine shop cut a couple of backing plates (3/16" or 1/4") and weld on some flanged weld nuts. A plate 2"x3" should suffice. Then you would use a router and route out a recess for the plate and drill a hole for the weld nut. Your rack wouldn't have a chance of pulling that connector out.

That would work as well, a couple other ideas I was thinking about:

-put three screws per foot (woud have to drill the other two), with twelve screws through 3/4" plywood, I doubt it would budge.
-use bolt with a 2"-3" washer, essentially it would have to rip through the entire area that the washer covers to move.
-use bolt with washer and not countersink. This method would require that I keep my 1/2 mats in place. Downside to this would be an extra half inche in height.

[sowilson]

That would work as well, a couple other ideas I was thinking about:

-put three screws per foot (woud have to drill the other two), with twelve screws through 3/4" plywood, I doubt it would budge.
-use bolt with a 2"-3" washer, essentially it would have to rip through the entire area that the washer covers to move.
-use bolt with washer and not countersink. This method would require that I keep my 1/2 mats in place. Downside to this would be an extra half inche in height.

I don't think a fender washer would prevent things from being pulled out as the problem is the lack of wood (around 1/4") resisting the pull. Don't underestimate how much force 300-500lbs on you back during a squat would have if you fell (or just dumped) and had the loaded bar hit the rear uprights. I'm afraid that leaving the 1/2" mats in place wouldn't work as they would be compressed over time - perhaps a thicker mat.

[gabeinphx]

I don't think a fender washer would prevent things from being pulled out as the problem is the lack of wood (around 1/4") resisting the pull. Don't underestimate how much force 300-500lbs on you back during a squat would have if you fell (or just dumped) and had the loaded bar hit the rear uprights. I'm afraid that leaving the 1/2" mats in place wouldn't work as they would be compressed over time - perhaps a thicker mat.

Guy at Home Depot recomenned these. Without having to countersink I would be left with a full 3/4 inches on the plywood. Can also add some material over the screw to ensure that there is no scratching (assuming it would not purtrude from the bottom, tighten enough to get a the bottom flush with wood). As an additional safety measure can throw in another two wood screws from the top.

http://www.homedepot.com/p/Unbranded...8811/202706160

[Freakin11]

I did have one other question. Is it ok to use a screw to secure rack to plywood, or does it actually have to be bolted from the bottom. Only reason I ask is I am only using one sheet and would have to countersink the bolt so the hardwood is not scratched, leaving less than 1/2 of plywood holding the rack in place. Thinking I could get more depth with a 3/4 screw (should not go through due to thickness of rack metal I will also be going through.

You could use Elevator bolts which would only requite minimal countersinking
www (dot) lowes.com/Hardware/Fasteners/Bolts/Elevator-Bolts/_/N-1z0yk5s/pl#!

[sowilson]

Guy at Home Depot recomenned these. Without having to countersink I would be left with a full 3/4 inches on the plywood. Can also add some material over the screw to ensure that there is no scratching (assuming it would not purtrude from the bottom, tighten enough to get a the bottom flush with wood). As an additional safety measure can throw in another two wood screws from the top.

http://www.homedepot.com/p/Unbranded...8811/202706160

Home Depot is the worst place to go for advice on something like this. Try a woodworking forum. Elevator bolts wouldn't be too bad. I would go with a threaded insert over the stuff the HD guy recommended. Do not underestimate the power that moving weight has. It's your rig, it's your life, attach it however you want.

[markewallace]

Home Depot is the worst place to go for advice on something like this.

Eh, I dunno. I have been really fortunate to catch some really sharp, creative guys working at my local Home Depot stores. I go in there frequently with little home gym DIY ideas, and rarely do I come away having been steered wrong. Could just be a YMMV thing.

- Mark

[gabeinphx]

Home Depot is the worst place to go for advice on something like this. Try a woodworking forum. Elevator bolts wouldn't be too bad. I would go with a threaded insert over the stuff the HD guy recommended. Do not underestimate the power that moving weight has. It's your rig, it's your life, attach it however you want.

Will look into the elevator bolts. Seems very similar to the plates suggested without having to have one custom made. Thanks again.

[Cleveland33]

Home Depot is the worst place to go for advice on something like this. Try a woodworking forum. Elevator bolts wouldn't be too bad. I would go with a threaded insert over the stuff the HD guy recommended. Do not underestimate the power that moving weight has. It's your rig, it's your life, attach it however you want.

What the guy from Depot recommended is a non-tapered threaded fastener, it need a nut on top of the rack to complete it. I would prefer that over a threaded insert in plywood. No countersinking necessary, it will pull itself flush with the plywood. The only problem with it is that you will have to have reach both sides (or have a partner) to tighten it. Also I think you're overestimating the pull the forces this is going to have go against it.

Will look into the elevator bolts. Seems very similar to the plates suggested without having to have one custom made. Thanks again.

Let's not complicate this any more than it has to be. Get some tee-nuts, I'd say 3/8" is sufficient. Put your rack on the plywood, mark the holes you want to drill. Drill through the plywood, hammer the tee-nut in place, put the rack back on it, and thread a screw in there. Simple, effective, and extremely strong.