(help) Alignment Table Size??

[anthonymaietta]

I am looking to upgrade my alignment table setup and I see one locally at a very good price.

Its 36" x 24" x 6" solid granite. Is this big enough?

What size tables do you guys have?

Thanks,
Tony

[Dave Kirk]

I use a 30" x 36" plate and let the rear end of the frame hang off the plate. I then use a 3/4" piece of square drill rod, 3' long, that I lay on the plate and let it hang off and reference the driveside rear drop to it. Very simple and super accurate. I think it would still work very if it was the size you are talking about.

Dave

[Archibald]

I am looking to upgrade my alignment table setup and I see one locally at a very good price.

Its 36" x 24" x 6" solid granite. Is this big enough?

What size tables do you guys have?

Thanks,
Tony

IMO, too small. If you had it already, I'd say go for it, but since you're shopping, get at least a 3' x 4'. Granite works, I've used one since I started, but a blanchard or Mattison ground iron/steel table is a lot easier to tool up for.

[anthonymaietta]

This may be a really dumb question, but how thick do you need it? Slabs of remnant granite are eveywhere from countertop makers. Can 1" thick granite be ground flat and used?

[Archibald]

This may be a really dumb question, but how thick do you need it? Slabs of remnant granite are eveywhere from countertop makers. Can 1" thick granite be ground flat and used?

The key word in "Alignment Table" is alignment. If you just want to QA frames, any documented flat surface will work. If you want to align, then you need something that can withstand the resulting forces and buck up your tooling. 1" would probably be fine for a steel/iron table if it had appropriate webbing underneath. For granite? NFW.

[Craig Ryan]

I have a 24"x36" cast iron table and it gets the job done. I will probably stick with it for space savings. You have lots of space, right?

[EnginCycles]

Don,
Tony might not understand that there is a huge difference between a cast iron surface plate and a steel slab of metal. I had a steel 1" table that was blanchard ground and it had a hook in the very far corner that was .015" off. Not something that would have much effect because it was not a datum point that would be used but still bugged me. It did not have webbing welded underneath but from what I understand that still won't solve the issue. Cast iron as you know is not prone to moving and will hold its tolerance after being ground. My current table is 3'x5' and is 8" deep with ground sides and webbing underneath. It is mounted on an insane table with like 20 set pins for leveling (which is funny because I doubt it has the ability to twist) and 2 locating pins for keeping it from shifting. I had it re-ground for like $250 locally and they said it was under .001" for flat. The ground sides are really handy for random fixturing. Magnetic drill press is much easier than dealing with the effort involved in putting holes in the granite IMO. Or get a t-slot ot platen table like Dave is using.

My $.02

-Drew

[Eric Estlund]

I have a 1.5" steel 3'x4' plate, and wouldn't want to go any smaller. It's not iron, and might not be as stable as a cast iron tooling plate, but it's way more accurate then tubes are straight. If I was building rocket ships I might want it flatter, but no issues building bikes on it.

It's about the max size I feel comfortable moving on my own, also a plus.


In this part of the world there are not a lot of used tooling plates- Eugene never had industry. Freighting something in turned a lot of the mid west / East coast good deals into prohibitively expensive ones. I had this plate purchased, drilled and ground in Portland for less then the steel cost in Eugene-

[Archibald]

Don,
Tony might not understand that there is a huge difference between a cast iron surface plate and a steel slab of metal. I had a steel 1" table that was blanchard ground and it had a hook in the very far corner that was .015" off. Not something that would have much effect because it was not a datum point that would be used but still bugged me. It did not have webbing welded underneath but from what I understand that still won't solve the issue. Richard's M&L table is that design and had a hook after time. Cast iron as you know is not prone to moving and will hold its tolerance after being ground. My current table is 3'x5' and is 8" deep with ground sides and webbing underneath. It is mounted on an insane table with like 20 set pins for leveling (which is funny because I doubt it has the ability to twist) and 2 locating pins for keeping it from shifting. I had it re-ground for like $250 locally and they said it was under .001" for flat. The ground sides are really handy for random fixturing. Magnetic drill press is much easier than dealing with the effort involved in putting holes in the granite IMO. Or get a t-slot ot platen table like Dave is using.

My $.02

-Drew

First & foremost, the key is to know what you're starting with. All you know about any old used steel or cast iron table you buy is that it's old & used. The material it's made out of tells you nothing about how flat it is. The same is true for used/old granite surface plates. It's the documenting and calibration of the surface that is important. Any surface that a builder buys to use as an alignment table needs to be documented regularly.

As far as steel vs cast iron, it's really a difference in how they're prepared. Cast iron is certainly dimensionally stable, but steel is also very dimensionally stable; plenty stable enough for an alignment table as long as it's supported correctly. For a steel table that's webbed, they're generally stress relieved before being machined and ground as those two activities relieve internal stresses and will cause warping, the same as it does in cast iron that hasn't been aged and stress relieved. Plus steel has twice the MoE of cast iron so you need less of it to be as stiff (and yes, improperly supported, your 3'x5'x8" table will & can twist which is why they go to all the trouble to make sure it is). Blanchard grinding a plain steel plate on one side that has not already been stress relieved and machined is a waste of time & money since it will be affected both by the grinding itself and any legs/whatever that are attached to it after the fact. A properly made webbed steel steel table that's been stress relieved, machined, and then kissed with a Blanchard grinder & documented will be plenty accurate enough as an alignment table and it's a no brainer to tool them up. Tables like the M&L and Bike Machinery's are typically done this way. I don't know how the Bringheli's are made but folks seem happy enough with them.

[EnginCycles]

First & foremost, the key is to know what you're starting with. All you know about any old used steel or cast iron table you buy is that it's old & used. The material it's made out of tells you nothing about how flat it is. The same is true for used/old granite surface plates. It's the documenting and calibration of the surface that is important. Any surface that a builder buys to use as an alignment table needs to be documented regularly.

As far as steel vs cast iron, it's really a difference in how they're prepared. Cast iron is certainly dimensionally stable, but steel is also very dimensionally stable; plenty stable enough for an alignment table as long as it's supported correctly. For a steel table that's webbed, they're generally stress relieved before being machined and ground as those two activities relieve internal stresses and will cause warping, the same as it does in cast iron that hasn't been aged and stress relieved. Plus steel has twice the MoE of cast iron so you need less of it to be as stiff (and yes, improperly supported, your 3'x5'x8" table will & can twist which is why they go to all the trouble to make sure it is). Blanchard grinding a plain steel plate on one side that has not already been stress relieved and machined is a waste of time & money since it will be affected both by the grinding itself and any legs/whatever that are attached to it after the fact. A properly made webbed steel steel table that's been stress relieved, machined, and then kissed with a Blanchard grinder & documented will be plenty accurate enough as an alignment table and it's a no brainer to tool them up. Tables like the M&L and Bike Machinery's are typically done this way. I don't know how the Bringheli's are made but folks seem happy enough with them.

The Bringheli is not stress relieved from what I gather and has chip board underneath that I think is attempting to make a cushion of some sort that is not pulling it if the stand is not as level as the top. It is bolted at all four corners through the board to the stand. I think it is more than good enough for making bikes but Tony is in an area that will have lots of stuff pop up. The very reason I had mine re-ground was I wanted to have a known starting point. They kissed the bottom, flipped it and took off .025" and left a few minimal marks that are below usable surface. I wanted a known datum and that is why I had it re-ground. No matter what the table I would have it ground before using it just so you have a known starting point.

-Drew

[e-RICHIE]

wtf does this mean atmo -

Richard's M&L table is that design and had a hook after time.

[EnginCycles]

wtf does this mean atmo -

You have mentioned on the list that you had your table re-ground because of it not being flat? Is that not correct? If so I will ask it be removed but I am honestly saying that from a direct conversation with you about the table and having it re-ground. Again I am not trying to put words in anyone's mouth.

-Drew

[e-RICHIE]

You have mentioned on the list that you had your table re-ground because of it not being flat? Is that not correct? If so I will ask it be removed but I am honestly saying that from a direct conversation with you about the table and having it re-ground. Again I am not trying to put words in anyone's mouth.

-Drew

that's not true at all atmo.

when i got my table, i was surprised by the built-in (or left-in) striations so i immediately had the surface blanchard (re)ground.
stupid newb american me, i came to realize that the lines were there so that the worker could shift the height guage back/forth
on it to remove any sticky flux deposits that might linger from the constant placing of frames on said table.

and i gotta chime in here - some (of you) guys seem overly infatuated with alignment and read out and all sortsa' tool shit atmo.
heck (asshat me for this...) i build about 800 frames before an alignment table even existed within the four walls of a shop i used.
i am seeing alotta money and alotta metal (and stone) in the internet era frame shops that dwarf the very output and knowledge
base that many of these players have.

[x] asshat

[EnginCycles]

that's not true at all atmo.

when i got my table, i was surprised by the built-in (or left-in) striations so i immediately had the surface blanchard (re)ground.
stupid newb american me, i came to realize that the lines were there so that the worker could shift the height guage back/forth
on it to remove any sticky flux deposits that might linger from the constant placing of frames on said table.

and i gotta chime in here - some (of you) guys seem overly infatuated with alignment and read out and all sortsa' tool shit atmo.
heck (asshat me for this...) i build about 800 frames before an alignment table even existed within the four walls of a shop i used.
i am seeing alotta money and alotta metal (and stone) in the internet era frame shops that dwarf the very output and knowledge
base that many of these players have.

[x] asshat

As requested above I will remove it from my post but the rest is up to you as the administrator.

[Carl S]

i am seeing alotta money and alotta metal (and stone) in the internet era frame shops that dwarf the very output and knowledge
base that many of these players have.

[x] asshat

I heart this sentence

[PCW]

i am seeing alotta money and alotta metal (and stone) in the internet era frame shops that dwarf the very output and knowledge
base that many of these players have.

Yeah, that's why I've been building on my table saw top, it's perfect for my one frame/quarter pace--and it makes me file those miters damn near perfect before I strike an arc 'cause I've seen what just a little bit of "off" does. It is case iron, ground, and big enough to lay out an ANSI E to build off of. Sure works great. That reminds me, does Joe sell just his alignment table post? I could drill a hole in a corner and mount that on there and have an alignment table too.

Thanks for reinforcing what I thought was already a clever idea for a guy like me that has no volume 'cause sometimes I get tool envy around here.

[EnginCycles]

double post

[steve garro]

I have the big Bringheli & I can bolt on a 29er touring bike with a 25" TT & 18.5" CS's & nothing hangs off the edges. - Garro.

[zank]

Tony, for reference, the table at my shop is 4'x3'. I like it because I have my fork alignment block mounted to it as well.

I went with a grade A (6" thick) granite plate because it was nearly free. The hammer drill and carbide tipped bits that I borrowed cut through it like butter. They pop up on Craigslist and eBay regularly for cheap. Most let them go if you're willing to get it out of their shop.

[zank]

Tony, for reference, the table at my shop is 4'x3'. I like it because I have my fork alignment block mounted to it as well.

I went with a grade A (6" thick) granite plate because it was nearly free. The hammer drill and carbide tipped bits that I borrowed cut through it like butter. They pop up on Craigslist and eBay regularly for cheap. Most let them go if you're willing to get it out of their shop.