Hi all, just joined and have a few questions. I’m a small time metal shop and have a 4x6 fab table with a very beefy frame and a 1" thick top, but it has about a 1/4" bow in it over the 6’ length and I think it’s about time I get something more flat. I really want a fixture table, but I can’t afford one. I do have a CNC plasma table and a mag drill so I was thinking about getting a 4x6 piece of 1/2" plate, then putting it on my CNC table and using an Easyscribe to layout a 4" grid on it, then use my mag drill to drill 5/8" holes in it. It looks like it’ll be 187 holes. I have two concerns…
Assuming I get a plate that does have a little bit of bow in it, will I be able to straighten it out with adjustable bolts or blocks or something, from below? Or is 1/2" just to stiff to be able to straighten out that way?
Since I’m not using a CNC to actually drill the holes, but just lining up the point of the annular cutter on the scribed grid, am I going to be able to get good enough accuracy that I’ll be able to buy standard 4" grid fixtures and be able to get pins in two holes anywhere on the table.
I’m not looking for .003 accuracy here, but if I buy some fixtures that have two holes in them, I want them to fit anywhere on the table.
I would consider getting Fireballs drill template jig, but do they still make that, and is it available in 5/8"? I guess I could make my own but I was thinking scribing it with my CNC table might work.
Can you post pictures of the frame you want to reuse? Or draw a picture of what it looks like and material used. This can help the forum group to come up with a game plan.
Here’s my take on hole placement accuracy. If the objective is to just use clamps and some slotted fixtures and use your tape measure to place your fixtures then the hole placement doesn’t even matter. You can randomly place the holes and be fine.
If you want remove human errors from the building process then I would suggest using a drill fixture and use a 2x2 grid. This will allow you to use tooth blocks, pins and shims to locate parts.
You could still use a scribe line from the plasma as a reference. I wouldn’t use the 5/8 stuff its pretty wimpy.
Go 3/4 and get the best of both worlds.
I don’t have a good pic of my frame since it has a table top on it, but I made it from 1/4” wall 2”x2” tubing, and 2-1/2”x2-1/2” receiver tube for the adjustable legs. My 48”x72” top overhangs the frame by I think 4” on each side, so the frame is around 40”x64” if remember right. I have more 2”x2” cross members inside the main rectangle and some receiver tubes below them for pull out extensions on the end and the side so I think it’s pretty strong.
I want the holes for more than just clamping, in fact I think I’m more concerned with an accurate grid pattern than flatness. I’ve watched your videos with extreme jealousy and have seen how easy it is for you to build accurate, repeatable parts with your tables. If I could afford any fixture table, yours would be my first choice.
I completely agree with a 2” grid pattern also, and would love to have it, but I’ve done the math and 187 holes seems much more attainable for me than the 805 holes I’d need for a 2” pattern on a 4x6 plate.
And as far as the 3/4” versus 5/8” holes… yes, I saw that video too. I’m not entirely set on 5/8” holes and could easily be swayed over to your 3/4” size. Especially since I’m pretty sure you guys don’t make a 5/8” drill template jig. I guess the reason I was thinking 5/8” is that it seems there are more companies that make 5/8” fixtures than 3/4” so I was thinking I’d have more options.
I’m also thinking about just having a 48”x72” half inch top, cut with a water jet for holes and skipping the whole drilling process. The company I talked to does laser and WJ but they can’t cut 1/2” with their laser.
Not sure I can swing that price since I’m just a part timer, but if I can I’m sure that would be the best option. I’m still concerned about flatness though, but again I really want to be able to use fixtures for squaring and measuring.
By the way… is there an update to your Star Wars office/staircase build that I missed?
I really like the adjustable bolt concept. Heat distortion and distortion due to weight of fabrication item means minor adjustments are possible. My table is made up of 4"strips with an adjustable bolt about 8" in from both top and bottom edges (long side). Its a small table (4 x 3). Spacing out the slats means tons of room for clamps. I also have an adjustable hinged side that i can fix at angles appropriate for fab too. Now im very new to fabricating (and welding - just retired and this is my hobby side gig treat to myself) and cant afford a real table but i can adjust this one to near perfect flatness and check it each time im setting up to weld something i want to stay flat. Havent had much to adjust yet.
If you look at about 26.5 mins and 30 mins you will see the template he made does not line up with hole in his table, if it was perfect it would.
If you watch again at 40 mins you will see he tries to drop his pin in and it does not go. (he edited that part out)
This will get you close on a small table but it will be far from perfect on a larger table.
Every time he says perfect just think close.
I wish he would measure from one hole to the next with calipers and show how close he is. Even a checking diagonals with a tape measure would help shed some light on how close he is.
Also remember he is not cutting very many holes but every hole he cuts wears the holes in the guide and with that will effect how close you can get.
This is why Jason’s guide has drill guide bushings in it that are hardened.
It all depends on how close you want to be. On this little 30x30 its probably close but its far from Perfect!
Have you had a go at heat straightening the plate you have, or the plate you want to use?
It’s somewhat of a black art, but the results are nothing short of amazing.
No i haven’t thought about straightening it with heat, I have hit it with heat before and it seemed to absorb so much heat I can’t imagine getting enough heat to try straightening it. I still haven’t figured out what I’m going to do but I’ll let you know what I end up doing.
Maybe I’ll win the lottery. I should probably start playing.
what if you accurately made 2 holes as close to perfect as your abilities allow? I used our manual mill/drill press to drill a plate. Then I dropped a couple of pins welding the plate to the pins. I used this fixture to mount the mag drill to where you can continue to leapfrog the fixture and drill this is how I did our table at work it worked great till I wasn’t the one drilling the holes and the guy that was thought 1/16 is close enough. maybe over 8’ but not over the 4" he was holding it to. SMH
I was saying that the jig that I made accurately would fit in the holes that I drilled but when my co-worker thought he could pull a tape and just mark the holes the jig doesn’t fit therefore the table is just a nice way to clamp things down and not a fixture table because he thought 1/16 was good enough.
@Zeke_Woodard I see this all the time in the DIY table world. If the job isn’t going to be taken seriously then the holes might as well be randomly placed. Most people see the holes as just a way to hold parts down with a clamp.
I’m in the process (2 years) of designing and building a fixture table for personal use. 3/4" plate steel, waterjet holes on a mixture of 2" and 4" spacing. Stiffners under the table cut with male keys to fit into the female key slots cut into the table top. This way I can push/pull the plate steel top “flat” to the stiffners and weld them together to achieve “flatness.” The stiffners will be “flat” from being CNC cut. 4’x8’ in size.
I saw an old posting somewhere on the interwebz of someone who built a table similar to this using only 1/4" plate steel. The idea is good but his material choice seemed way too light for typical shop use.
My everyday work bench is 1" plate steel welded to a channel and I-beam frame, it’s not “flat” but does the job for everyday needs. My wood shop is 3/4" plywood table on a landscape timber frame, serving as an outfeed table from my table saw. I plan to put the “flat” fixture table in the wood shop. If I like it, I’ll build another for the main shop.
If building your own, I’d find a waterjet shop that has taper compensation so your holes are not tapered. Or a laser that can cut steel thick enough for your needs. Drilling all those holes by hand sounds like punishment.
If I had a table with 3/4" holes and stumbled across a really good deal on 5/8" fixtures (or just something unique that I really wanted) I bet it’d be easier to put a bushing on the 5/8" pin to fit a 3/4" hole than fit a 3/4" fixture into 5/8" holes.
