MY take on well known Bender

**ncollar** · Jan 14, 2018, 06:37 PM

Garage nut
One thing you might want to do is make a "D" reamer. They are easy to make and will open a hole just a few thousands
creating a nice round hole. Google "D" reamer.
Good Luck.
Nelson

Here is a pdf file on reamers for some ideas. http://billhaneman.ie/Reamers.pdf

**olderdan** · Jan 15, 2018, 04:05 AM

Originally Posted by ncollar

Garage nut
One thing you might want to do is make a "D" reamer. They are easy to make and will open a hole just a few thousands
creating a nice round hole. Google "D" reamer.
Good Luck.
Nelson

Here is a pdf file on reamers for some ideas. http://billhaneman.ie/Reamers.pdf

Absolutely correct, D bits or reamers have been used by model engineers for years to good effect.
Largely forgotten these days with so much cheap tooling available but still just as useful, especially when a blind hole has to be sized to the bottom face. They do need to be machine controlled in use.

**garage nut** · Jan 14, 2018, 09:42 PM

I did 40 tests

on the 4 pieces to make the main frame, used the same steps. I used a 13mm before the 16mm and the holes in the frame members I all had to polish with the Dremel to get the 16mm Pin go in. Was so tight I finally opend then firther with a 16.2mm drill. That was fun as the drill almost "SCREWED" itself into the hole. All done on a very old very inexpensive pedestal drill.

Will try a 12mm drill next time and see what it does.

**garage nut** · Jan 16, 2018, 09:48 PM

Got going with the next part. The adjustable guide that is used to rub against the item you are bending whilst bending it round a pin. They describe it as the eyelet bender.
So started by cutting it at its prescribed angle of 70Deg. Used the old faithfull abrasive cutter, but with some serious clamping to its bed.

Then I had to machine a 10mm slot just longer than the pitch of the holes in the main frame. This leads me to why I am posting this pretty insignificant fabrication.
What is best, for the mill, to mill this slot remembering this is a very small machine and the distance from the spindle bearing to the vice is uge. I am basically on max extension to get the cutter to go past the pot of the vice and the the cutter as far out of the collet as it can go.

Do I mill with say a 6mm cutter down the one side and up the other or do I use a 10mm cutter and do the slot in one go.

MY take on well known Bender-guide-2.jpg

I ended up, as I did it last night, with drilling as much as possible out first and the ran the 10mm cutter taking .2mm cuts every pass. Had to turn the block around to be able to do the full depth