Proper Bolt Size (Thread & Pitch) for Heavy Load?

[T411]

I want to use bolts as leg levelers on a welding table that weighs 2000 lbs. What size bolt size bolts should I use? I will drill and tap the table leg base plate that is 4” x 4” x 1/2” thick.

 

[memphisjed]

1/4 20 will hold that up, flimsy foot- maybe go 3/8 with 325 bolt for the bigger head and less dangly foot. tap less likely to break too.

 

[JS]

I used these on the last table

[ Socket-Mount Leveling Pads & Mounts - MSCDirect.com ]

 

[tommy1010]

How many legs??? 4, six, or eight? If four (500 lbs per leg) I would use 1" 8TPI bolts for the levelers. I would also weld a nut inside the leg on that 4x4 plate. Just drill the plate oversize. Repeated banging on table won't fair well with just a half inch of thread. Make the plates for the floor contact at least 3x3. IMHO should do fine. Almost forgot. Put jam nuts before installing into the legs.

 

[Tony Quiring]

You can buy ready made feet.

They have a ball jointed base and correct type of threaded "leg".

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[Illinoyance]

Don't forget the welding table may see horizontal forces especially if you need to move it. That will tend to bend the leveling bolts. I would suggest 1/2" bolts.

 

[T411]

4 legs, 2 tables.

Thanks for the replies.

 

[T411]

How many legs??? 4, six, or eight? If four (500 lbs per leg) I would use 1" 8TPI bolts for the levelers. I would also weld a nut inside the leg on that 4x4 plate. Just drill the plate oversize. Repeated banging on table won't fair well with just a half inch of thread. Make the plates for the floor contact at least 3x3. IMHO should do fine. Almost forgot. Put jam nuts before installing into the legs.

Yeah I was thinking that I should use between 3/4” and 1” but I usually over build. Probably better that way. I got some 4”x4” 1/2” plate that I was going to use under the existing bottom plate.

 

[DDoug]

Use 1"-8. That way, extending them a couple of inches won't bend them
with the aforementioned side loading.

Also, are you placing 2k lbs on gently ? or is there some impact ?

weld nut on top of plate (so it's concealed up inside leg)

too small and you have to re-do it, too big, you just spent a small amount too much.

EDIT: I see tommy thinks the same as I doo....(now that's scary...)

 

[EPAIII]

Almost any bolt or screw will hold up to that load if you only consider the compression load. The thread would fail first and you could probably go even smaller than 1/4 - 20.

BUT and that is a BIG "BUT", there will be other loads on those bolts used as feet. Horizontal forces will put them under torsional stress and I suspect that 1/4 - 20 bolts will bend after just a little use. They are far too small for a heavy welding table and the forces that the feet will be subject to.

Just a seat of the pants estimate but I would start with a 1/2" size. AND try to keep the diameter less than or equal to the distance between the bolt head and the leg's bottom that it is threaded into. If you get into larger bolt sizes, you could probably go with 1.5 or even 2 times that distance. So, if they are going to stick out 1" a 3/4" bolt would be a good choice.

1/4 20 will hold that up, flimsy foot- maybe go 3/8 with 325 bolt for the bigger head and less dangly foot. tap less likely to break too.

 

[Cole2534]

Use 1"-8. That way, extending them a couple of inches won't bend them
with the aforementioned side loading.

1"-8 would be my choice. Rather than bolts, look into grabbing a length of B7 all thread. It's dirt cheap, about equiv to G5 in hardness/tensile and made of 4140.

There's no reason that just about any shop shouldn't have lengths of B7 in various sizes about, it's so damn handy.

 

[DDoug]

1"-8 would be my choice. Rather than bolts, look into grabbing a length of B7 all thread. It's dirt cheap, about equiv to G5 in hardness/tensile and made of 4140.

There's no reason that just about any shop shouldn't have lengths of B7 in various sizes about, it's so damn handy.

Yup, I was considering the OP's only source was "tractor supply"....

weld a nut on the end (plug weld by leaving the nut proud of the end of the thread rod) and use that on the end contacting the floor.

 

[T411]

Thank you all for all the replies. I had both tables 5’x5’ set up next to each other with a 2’ gap. The floor was dead nuts and my tables were parallel. I just moved and they are obviously not parallel to each other now.

 

[Blazemaster]

I bought 2 sets of these last year, one for a table like yours and one set for a milling machine. They are nice quality, I could use about 3 more sets.

Snaplock LP3 Anti-Vibration Leveling Mount, 8.5", 5/8-11, 3" feet 4800# (Qty-4) | eBay

 

[DDoug]

I bought 2 sets of these last year, one for a table like yours and one set for a milling machine. They are nice quality, I could use about 3 more sets.

Snaplock LP3 Anti-Vibration Leveling Mount, 8.5", 5/8-11, 3" feet 4800# (Qty-4) | eBay

Uhm….yeah.

How is the rubber going to maintain level as the 2000 lb weight comes on and goes off ?

And how about sparks ?

The op indicated it's a "welding" table ….You know, with "fire & sparks" ?