Thread: Finding the centre of a rod

Originally Posted by tomhowell

You need to square up the drilling machine table to the spindle (front to back & side to side) to drill holes square.

Then your workpiece needs to be held square to the table.

A simple but useful way to do this is to get a thickish bit of wire approx the radius of the table plus a couple of inches.

Bend an inch or so on one end at 90 degrees, then bend an inch or so the other end at 90 degrees but in the opposite direction, resulting in a sort of elongated Z shape.

Chuck one end in the drill chuck, then raise the table or lower the chuck so the outer end of the wire scrapes the edge of the table.

If the table is square to the spindle right around, the wire should scrape the table evenly right around as you rotate the chuck by hand.

If not, square the table up by pivoting it side to side; many tables have an adjustment bolt near the pivot to adjust the table front to back.

If you can't get the adjustment you need, make up a false tabletop and shim it level.


HTH............cheers..................Sean

Originally Posted by scooter

Bend an inch or so on one end at 90 degrees, then bend an inch or so the other end at 90 degrees but in the opposite direction, resulting in a sort of elongated Z shape

I think Scooter is referring to something like this

Yup

Hi Jeremy,

Like you, I tried unsuccessfully to find exactly what you were looking for,
so I knocked up a quick drawing.

The two parts, A & B, I recommend laser cutting from 2mm s/s, the grade doesn't really matter. What will matter is how well you align the two parts.

On part B I have shown a chamfer, this is optional but would aid to scribing your line.

Attached is a drawing, unfortunately I was unable to attach two dxf files for the Laser Cutter. If you send me a private email, I will email them to you, and anyone else, if interested.

If someone knows of a work-around for dxf files, please respond.

Good luck,

Regards,

Ken

Another simple way, is to lay the rod down on a flat surface, then with a height guage or similar lower the scribing edge half the thickness of the rod and mark several lines as you roll the rod on the surface. Doesn't even have to be a height guage, can even be a scriber fastened to a block of wood as long it is somewhere near half the height of the rod.
Always centre punch, then centre drill then drill the diametre you want.
Hope this helps.

Squirrel...

Ken, you could archive them into a zip, then upload the zip file.

Or you could maybe change the file extension to, say, .doc, then add a note to rename the file after downloading.

Will investigate whether we can add DXF files to the list.


Cheers..................Sean, moderator

Thanks for the work-around Scooter.

I have attached two files Part_A & Part_B. They are shown as doc files,

but are secretly dxf files, so you will have to change the file ext from .doc to .dxf, before you can use them.

Would a kind member let me know if this procedure works, if it does, then Bob's my Uncle.

Ken

I am answering my own question here.

Attaching the dxf file as a .doc file, then opening it with Word, then saving it as a .dxf file, to my Desk top, works. I just tried it. So there you go. Thanks Scooter.

Ken

Dear members,

I have drawn up a smaller version of the bar centre finder.

Attached is a drawing, and two .dxf files disguised as .doc files.

Open the .doc files in Word, then save them them as .dxf files.

The dxf files are for the Laser Cutter.

Ken

Wow, what a lot of great stuff - I will check the "verticalness" of the table to the quill and look at Ken's gizmo. It cetainly looks the goods

Thanks everyone

Have enabled dxf in the attachment area (max file size 250000) no idea if it will work. Someone please try it out.

Cheers - Neil

Trial for .dxf attachments

These are the dxf files of neksmerj's centre finder

Thanks to Neil & Wood Butcher.

Yep, works fine, I was able to open the dxf files directly with Autocad 2002.

Ken

this is what I do...
extend your spindle, give it a shake.... The backlash in this will indicate how much backlash you have in your machine and how accurate you can drill your hole...
holding your workpiece vertical you can put your drill bit in the chuck...
spin chuck and see how much it wobbles, if it is nice and true you can line your job up square to the drill bit.
If not using a rule, place on extended spindle and eye off to job in two spots perpendicular to job.

drilling center.
get a center drill
get a chunk of blue tack and a nail.
put chunk of blue tack onto side of center drill, push nail into bluetack
spinning the chuck and the nail around job you can eye off the OD of the rod.
its sounds rough, but it does work..