Anyone made their own mill parallels and if so, what tolerance is ok?

[jocat54]

An older retire guy gave me a handfull of HSS cutting bits 3-4" long, 1/4" & 3/8" square several years ago. I've been using them as singles, pairs, stacked, and stacked pairs. The tolerances on them seemed very good and for setup on a milling machine they perform quite well, at least on my small home miller. I've never checked for price, I wonder how they compare with purchasing "parallels"?

That is what I use most of the time--seem to work for me.

 

[DMS]

A set of soft jaws may fit your needs. These are vice jaws that fit in place of the stock (hardened) jaws. Typicaly made from mild steel or aluminum, you can bolt them on and machine them in place. As long as you don't remove them, tolerances are very good. You can also mill a small ledge near the top which serves the same purpose as a set of parallels. I have been using a set made from aluminum for a couple weeks and really like them.

 

[Pontiac Freak]

I wanted to learn how to use my fly cutter and other tooling so I made my own. Started with 1/2" plate and cut to size. Surfaced them together and then heat treated them. Took them to work and learned how to use the surface grinder and made them matching on all sides Could have bought them cheap, but I learned a lot making them so it was worthwhile for me.

 

[easymike29]

I wanted to learn how to use my fly cutter and other tooling so I made my own. Started with 1/2" plate and cut to size. Surfaced them together and then heat treated them. Took them to work and learned how to use the surface grinder and made them matching on all sides Could have bought them cheap, but I learned a lot making them so it was worthwhile for me.

Pontiac Freak

Let me congratulate you for your effort. Too often the prevailing wisdom is "I can buy cheaper than making" As you have demonstrated, there is a lot to learn about machining whether a hobbyist or working in a shop. I would encourage you to also make sine bars/plates, Vee blocks, toolmakers vise, and even a radius dresser if you do much surface grinding.

When I was still in the working world my apprentices had to make a set of four 1-2-3 blocks, all flat, parallel and square in all directions within .0001" T.I.R. before they could be trusted with any of the tooling we fabricated. The .0001" T.I.R. had to be demonstrable with a dial test indicator, not a cylindrical or other type of light source method.

Gene

 

[Frank Ford]

Indeed, it does depend on what tolerances you need. I do LOTS of "casual" work, so I made up some disposable parallels that I can drill or mill into without worry. In fact, one of my most used parallel sets is made of wood - for use on the drill press, thus:



I also made up a big batch of aluminum ones for the mill:



I can also use them for filtering by milling or drill features into them for specific work holding.

For more serious work, I bought the usual sets of 1/8, 1/4, 1/2 inch thick ground steel parallels.

 

[Mid Day Machining]

When I need special parallels, I make them out of 1/8 or 3/16 inch thick 7075 aluminum. Then when they get beat up, I'll cut them down to a clean up and keep using them. As long as you make your parallels straight and the same size, who cares what you make them out of as long as they work for you.