Transferring measurements

[gtivr4]

Seems like there should be a simple solution to this, but I haven't found it...

Lets say you have an object you want to mount on a piece of steel, in this case a steering rack onto some tubing. The steering rack has three 1/2-20 mounting holes. How do I go about accurately measuring their location and transferring that to the steel? I can get it close by eyeballing it, but not 100% accurate, especially measuring from the center of a hole.

 

[bobadame]

If the threaded holes are through holes you could use a transfer punch. In the case of 1/2-20 that would be a 29/64 punch. If the holes are not drilled through you use transfer screws. Another way is to thread a couple of 1/2-20 bolts into a pair of holes. Measure over the outsides of the bolts with a dial caliper. From this number subtract 2 radiuses, one diameter. This will give you the exact center to center dimension for that pair. Now is when you will need a Bridgeport or at least some kind of x y translation stage under your drill press. If you don't have these you can lay it out pretty accurately with a dial caliper and a straight edge. Center punch the position of one of the holes. Then set the dial caliper to the center to center dimension of the pattern. Place one of the ID points into the center punched divot and using the caliper as a scribe, swing an arc to give you the distance to the center of the next hole. Then with a straight edge mark a line to connect the center punch mark to the center of the second hole. Continue this process with the other 2 distances.

 

[Heavy Metal Doctor]

Another way to do this if the holes are blind is to lay the part on some heavy paper or card-stock (Ive used file folders I stole from the office and even rolls of painters masking paper for big stuff) you can use a smal ball-peen hammer to tranfers the holes by tapping lightly around the holes. The hammer "pinches" the paper and tears it. If you do it carefully and hold the material securely in place (don't let it move around while transering holes - tape it down if you must) you end up with a template you can use to layout the holes on your workpiece. You can even mock up the positioning of the part to be mounted when you use more rigid stuff like the card-stock.

 

[rwhite692]

+1 for transfer punches. You can get a set from Harbor Freight for around $10.

 

[Griff93]

http://www.mcmaster.com/#transfer-punches/=8xo4vr

These work very well if the holes don't go all the way through. I have bought several sets and used them more than I thought I would.

 

[jakeb]

Is there anything that mcmaster doesn't sell?

 

[Stick]

Seems like there should be a simple solution to this, but I haven't found it...

Lets say you have an object you want to mount on a piece of steel, in this case a steering rack onto some tubing. The steering rack has three 1/2-20 mounting holes. How do I go about accurately measuring their location and transferring that to the steel? I can get it close by eyeballing it, but not 100% accurate, especially measuring from the center of a hole.

Never measure from the center of a hole if you can get away with it. Measure from edge to edge, and offset your measurement by the radius of the hole to put yourself back on center.

Example:
O_______________O___O
Measure from the left side of each hole, and offset by 1/4" to the right for the center of your 1/2" holes. The measurement between each hole doesn't change whether you measure from edge to edge or center to center, you just have to take into account the offset when you measure from the edge.

You can use a T-square or a piece of angle iron to scribe a line on the center of the pipe to make sure the holes are lined up straight.

 

[Jim51]

I' have a ball of duct seal (like Plasticine) in my tool box that I use for that sort of thing all the time. Just roll it out like dough as thin as you like on the steel plate. Press the object you want to transfer into the dough, pull it away, then mark, cut and drill to your hearts content. You can buy a 2 lb block of it in most hardware stores for around $2.50.

 

[MP&C]

http://www.mcmaster.com/#transfer-punches/=9369jj



We normally install these, then hold in place with some tape. Position your part and whack with a dead blow. Done. More affectionately known as tittie pins.

 

[LEVE]

Is there anything that mcmaster doesn't sell?

Yes, unlike HF, McMaster doesn't sell junk.

 

[drmarkr]

Yes, unlike HF, McMaster doesn't sell junk.

And McMaster transfer punches are better than HF's in what way??

 

[ironheadtom]

And McMaster transfer punches are better than HF's in what way??

I too, am a big fan of Mcmaster. Great customer service, and every tool I have ever bought from them is a quality item. Punches and chisels from H.F. generally don't have the hardness of real tools. Their stuff will work but the points go flat easy and unlike a regular punch or chisel..you cant re-sharpen a transfer punch by hand.

 

[tdkkart]

And McMaster transfer punches are better than HF's in what way??

Buy a set from HF and let us know how long the points last when punching steel or stainless steel.

 

[tdkkart]

Is there anything that mcmaster doesn't sell?

Good looking women........

 

[Big Rick]

the scrue in tranferpunchs work well for threded holes the blind hole are ok but dont fit as good as threded ones. Ihave 4 sets of reg thrue hole punchs 1good set for taping on 3 cheep to help hold part in place while marking centerwith good punch.Tap alight mark then go back with real center punch a teansferpunch is just mark the hole then go back an use a good clean sharp center punch .I use magic marker as lay out die most of the time the lite punch will mark the die to make it easer to see punch mark

 

[Ign]

Yeah, don't expect HF transfer punches to last. McMaster can be spendy, you can get any decent set of transfer punches from Enco, MSC, Rutland or Travers. If it only specifies "import" as a brand name and is under $15, consider stepping up a notch.

 

[PAToyota]

Smear the piece with the holes with a thin coating of grease and press it against the part you're going to drill out. You'd be amazed at how clearly the image of the holes is transferred.

 

[tdkkart]

Is there anything that mcmaster doesn't sell?

They don't sell junk.
Anything else, if they don't have it, you don't really need it.

 

[Mario428]

They don't sell junk.
Anything else, if they don't have it, you don't really need it.

X2 on that