Any ideas on a quick way to square up a workpiece on the mill table?

[ChazzC]

I use a number of methods to quickly align a workpiece on the table; some are usually close enough so they don't need further checking, others get me very close so the part can be tapped in as in @Karl_T 's post and as you would do to tram in your vise.

Quick & Dirty #1
I drop a pair of 12mm Dowel Pins in the T-Slots (12mm fit perfectly in my Mini-Mill),


and push the part up against them (this is what you would see from the back of the mill):



Quick & Dirty #2
I lay a long 31/64" Dowel Pin (or in this case a Drill Blank) in the T-Slot; on my Mini-Mill, 31/64" drops deep enough into the T-Slot to locate and can't be pushed out by the workpiece (again, view from behind):



Quick & Dirty #3
Machinist Square:



If you need to mill edges of the workpiece, you can use stand-offs (@Karl_T ) or 1-2-3 Blocks and push the part against the Dowel Pins, or push one the 1-2-3 Blocks against the pins and align the part with the edge of the 1-2-3 Block.


Another method is to use a Fixture/Tooling Plate which is aligned to the mill:

The three plates at the top were cut from a Sherline 13" x 7" plate, and have mini-T-Slots and reamed 0.250" holes that can be used for workpiece alignment (also 10-32 tapped holes for use with toe-clamps). The other plates have 1/4-20 tapped holes that are accurately located & uniformly countersunk on a CNC Mill, like the holes on this SMW (Saunders Machine Works) plate (mine is a 10" x 6", which is not currently available; I wanted to be able to use it without removing my vise):

I have a Hobby SMW Mod Vise mounted on the plate which gives another option for holding & aligning.

Saunders makes special 1/4-20 Fixture Pins that locate on the countersink of the 1/4-20 holes:

0.250" Dowel for Sherline (top) and SMW 1/4-20 Fixture Pin (bottom)

 

[mmcmdl]

Like Chazz #3 , I use a Starrett master square then indicate . Mount a bar to table to relocate multiple parts . Usually its a rotary table or indexer I mount . One of the Hardinge indexers was ground parallel so I could throw it in the vise for easy setups .

 

[ChazzC]

Like Chazz #3 , I use a Starrett master square then indicate . Mount a bar to table to relocate multiple parts . Usually its a rotary table or indexer I mount . One of the Hardinge indexers was ground parallel so I could throw it in the vise for easy setups .

I frequently hold the small fixture plates in the vise's outer jaws, and when I "fixed" my SpinDexer I machined the base square to the axis so I can clamp that in the vise, too.

 

[Huub Buis]

Could you explain? I'm not new to machinging, but I don't understand this answer.

Mount an angle block on the table and align it, the same way you would align your vice. Now that angle block is your fixed jaw.
Place 123 blocks (spacers) on the table to get the part at height, the same way you would use spacers in your vice.
Now clamp the part to the angle block. Clamp it the same as in your vice, using a thin wire at the back of the part so the part is flat with the angle block.

Once the angle block is aligned, you can replace parts quick and easy. It still isn't as fast as the vice, but you only align the angle block once.

 

[homebrewed]

Normally I would just use a square on one good edge.

For something floating like you’re describing, do your setup along with hold downs in place but not tight.

Lightly snug one corner and put a dowel pin in the mill. Bring it to near the corner that is snug and use this as a reference with your DRO, then bring the adjacent corner/edge into line.

After that bring out the indicator.

This is pretty much how I do it. I've used 123 blocks to elevate work when I needed to thru-drill or clean up an edge but the blocks had this annoying tendency to scoot around as I was doing the rough alignment, so I made some 3D-printed blocks that had counter-bored holes for hold-down bolts. No more 3rd hand needed.

They are basically sacrificial, which can come in handy for some jobs. A couple of them have a few holes in them but they still are fine for what I need.

 

[RaisedByWolves]

This is pretty much how I do it. I've used 123 blocks to elevate work when I needed to thru-drill or clean up an edge but the blocks had this annoying tendency to scoot around as I was doing the rough alignment, so I made some 3D-printed blocks that had counter-bored holes for hold-down bolts. No more 3rd hand needed.

They are basically sacrificial, which can come in handy for some jobs. A couple of them have a few holes in them but they still are fine for what I need.

Some times you have to get crafty and there are many times through the years where the ability to 3D print a fixturing part would have been a godsend.

I've worked on mostly industrial equipment and stamping dies and always wound up being the guy they took the jobs no one else wanted to do to.

Scariest job I even got was a bearing pocket in a case for some ancient Harley motor for one of the foremen at work.
The part was unobtainium and the bearing spun in the pocket. There was ONE bearing that could fit and there wasn't much to hold the case down with and no wiggle room for error, and little to reference a zero from.

Best job, again for a manager at work, was a shaft fitting for his 46' Beneatu sail boat. Went down and installed the parts, and he had mentioned we would go out sailing a bit afterward to try these out. Never said his girl friend and her friends were coming along later with food and drink.

That was a day.

Anyway, there's always a way to do something, you just have to think it through.