MY take on well known Bender

[garage nut]

To hot to be out on the boat yesterday so started the bender I have have wanted to build for some time, but always had something more pressing to do.
Main body called for some 2.5" x 0.5" material. All I had in the garage was some 50 x 10mm stuff so decided that will do. Been lying in the garage for so long I can not even remember for what i bought it so all it meant, I was going to build an 80% scale model

Worked out very nice as the pins to be used are 25/32" almost 20mm in what I can understand...Also not a standard size I keep, but 80% of that is 16mm and that i have lots of.

So here is the main body.

[ncollar]

Garage nut
I am watching you. By the way how is the hacksaw doing?
I enjoyed watching the R&D.
Nelson

[JD62]

Nice to hear its warm there it was -10* F here this morning

[ncollar]

Yes, our weather puts a damper on a lot of things. It has been below 50° here for about 6 days and I am getting cabin fever. I got in my shop last week about 10 minutes and that was all I could stand. Florida is not this cold as a normal for this long. Where is the sunshine? Maybe someone could close the freezer door.
Nelson

[garage nut]

The saw is waiting on a more powerful power supply, but summer is here so I am pushing like hell to get my boat finished before the winter comes. so at this point in time I do a bit better planning and get my steel merchant to cut to size for me

[garage nut]

Today I made the "Eye Pin" according to the drawings I downloaded. A little different. Had to fit a grub screw as My 16mm drill decided to drill about 2/10 big. This is strange as I did drill several bigger and bigger pilot holes.

[olderdan]

garage nut,
In my experience the final drill has to have some metal to remove otherwise it will not be guided by the cutting edges and start to wander and even go out of round.
Maybe use less steps, drills cannot work like reamers, I would say for a 16mm final drill leave around 4mm undersize, plenty of cutting oil and machine feed if poss.
If size is important try a test piece first. One downside to step drilling is that the outer lands of the drills will not last long.

[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

[garage nut]

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.

[olderdan]

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.