Tricks of the trade when aligning things?

[slow-poke]

My background is in electronics. Machining and fabricating is simply a fun hobby and I have much to learn. One issue that I’m clearly not great with is precisely locating mounting holes (when I don’t have a reference drawing) particularly when they need to be in some fixed and often awkward to get at location and the thing to be mounted is an odd shape that therefore needs to be mounted on standoffs brackets etc. More often than not one of my holes ends up being off by a mm or two.

I would imagine the seasoned pros would have a trick or two that they have picked up over the years for “perfect alignment“, please share if you do.

This is my next project: https://www.hobby-machinist.com/threads/drilling-head-of-round-column-mill.103204/

I’m anticipating issues locating the bottom mounting block precisely so the rectangular tube is perfectly parallel to the head. Eventually the rectangular tube will need to be severed, but it seems logical to make that cut after the tube is located and bolted at both ends in the fully lowered position.

if you have something to share please do, thanks.

 

[hman]

A very simple trick is to clamp the parts together securely, then drill thru both simultaneously (ie, match drilling).

 

[jwmelvin]

Two issues: locating holes; and aligning parts.

For locating, @hman raises a good approach if you are drilling in both parts. Similarly, if the outside part has holes that you want to match in an underlying part (like a bracket with holes that you want to affix to something in which you will drill holes), then drill and tap one hole, insert a fastener, then drill additional holes. The fastener will insure that the outer part does not move.

If you have holes in the inner part (like a machine base) and want to match those to holes in an outer part (like a bracket), you can use transfer screws, which would have a small point protruding, so placing the outer part on and tapping with a hammer creates a dimple mark in the mating surface of the outer part. Some transfer screws are threaded like pointed setscrews, and others just sit in the thread ID.

Aligning parts is a slightly different issue, in my view. If you want to insure alignment, don't locate using a threaded fastener. Use another feature (dowel pins, machined edges, etc.) and then use a fastener with clearance to clamp the parts together. A shoulder screw into a bore can provide precision locating, but it's easier and less expensive to separate the two functions into different structures. For locating features, you could use an external jig, or external measuring device to adjust the alignment before clamping. Once you align and clamp, you can drill a hole through both parts and insert a pin so that the alignment is captured and repeatable.

 

[C-Bag]

A good set of transfer punches, a good auto punch, learning layout with dykem with a scribe, and transfer buttons are all tools in the arsenal.

 

[Deleted member 69715]

When you get your layout done, will this be a square or rectangular hole pattern? If so, you'll want to double check for squareness by measuring your layout positions diagonally. Just because your hole centers measure up and down or side to side the same , it does not mean they're "square".

 

[markba633csi]

Drilling holes where you want them requires making a dimple with a punch for your drill to follow. You should have some Dykem layout fluid
and a scribe to do this, plus a sharp centerpunch or prickpunch. A good 6" steel rule is essential, and a caliper too, when locating from an edge.
For holes bigger than about 1/4" it is a good idea to use a smaller pilot drill first then the larger drill
Practice, practice, practice

 

[Kiwi Canuck]

Probably not much help, but I had the same frustration when making brackets and jigs, if I needed any more than 2 holes in a piece that was drilled and tapped, usually one or more would be out of alignment.

I was using a drill press with a cheap vise or doing by hand with a cordless drill.

I had some success by this trick, when measuring the distance between 2 holes, measure from inside edge of one hole to the outside edge of the next hole, this gives you the equivalent of center to center measurement, pretty simple but helped me as I would always try to eyeball the center of each hole with my calipers which was a crap shoot at best.

I also got a set of transfer punches, awesome, can't live without them now.


Buy a good quality set of magnifying glasses and add LED Lighting to your work area, sometimes my center punch missed the mark and I didn't notice.


As others have said, use Dykem for laying out lines.


Or buy a PM935 Mill with a DRO, problem solved, that's what I did, now I love making jigs and brackets.



Good luck

David.

 

[Winegrower]

buy a PM935 Mill with a DRO, problem solved,

Yep, this is what changes a drill press into a mill.

Ok, sure…but you know what I mean.

 

[Ulma Doctor]

I’m partial to scribing lines on the work pieces wether i use dykem or a sharpie.
Clamp up.
I tend to drill a single hole and tap appropriately, and fasten the 2 pieces together. The next hole is drilled. The assembly is taken apart and the second hole is tapped. Once reassembled, subsequent holes can be drilled without disassembling the assembly.
Disassemble to tap any holes.
Finish parts and reassemble

 

[Provincial]

If you center punch for a hole, strike the punch lightly, then check to see if the mark is where you want it. If it is good, go ahead and make the mark as deep as you need to get your drill located.

If it is off a little, you can "walk" the mark into position. Do this by holding the punch at an angle so the point will move toward the point you want. It is a gradual process, peening the metal as you go. Keep the point of the punch in the dimple made, since you are moving the dimple.

Try this out on some scrap and you will see what I am talking about. Practice a little, and you will pick up the skill very quickly.