Holding Thin Parts

[sparky961]

This one seems so obvious that I'm sure there are a number of you guys out there that use it already.  But remember that few things are obvious the first time around.

The problem is how you hold a very thin part on edge for machining, when your parallel is thicker than the part.  The solution?  Use another parallel (or anything else lying around) as packing between the part and the moveable jaw.  Of course, keep the part as low in the vice as possible and cut so that the force from cutting doesn't twist the part out of shape.  If extremely thin, you'll need to reduce your depth of cut accordingly so as not to damage the part.

[Stilldrillin]

I'm sure there are a number of you guys out there that use it already.

Sparky.

I'm one of those guys.

But, as with any rarely used technique, it's good to have a reminder occasionally....... 

Well done! 

David D

[Lew_Merrick_PE]

Another aspect on this that I have a set of blocks that are thinner than my usual suspect parallel used to clamp the "top" of the part that are tapped 3 places in a "V" pattern.  Fit into those tapped holes are hex head cap screws that I turned the top face to a (convex) spherical shape that will support my parallel.  This reduces the need for as many arms as Shiva when making the set-up and supports the clamping parallel if I have to trim more than a single part!

[sparky961]

Another aspect on this that I have a set of blocks that are thinner than my usual suspect parallel used to clamp the "top" of the part that are tapped 3 places in a "V" pattern.  Fit into those tapped holes are hex head cap screws that I turned the top face to a (convex) spherical shape that will support my parallel.  This reduces the need for as many arms as Shiva when making the set-up and supports the clamping parallel if I have to trim more than a single part!

It sounds good, as the setup is admittedly hard to hold.  Pictures would help though, as I can't quite envision what you're describing.

[steampunkpete]

Clamping the thin component between two bits of sacrificial scrap is another possibility.

Once I soldered six thin sheets together, then machined and de-soldered. This yielded a number of identical thin components.

One could also solder a thin component to a piece of scrap.

There is always a way Grasshopper 

[sparky961]

There is always a way Grasshopper 

Very true, and the only way to think when confronted with something that's proving difficult.  The key sometimes is to come up with the simplest and quickest solution that gets the job done within appropriate tolerance and time.  Trying to use things already in front of you is one way to accomplish this.

Arguably this is less of an issue in the home shop, as you can take as much time as you want.  But a bit of efficiency there helps you get more done and build more and more complex things.

[Jasonb]

I've used this method a few times, use a thin steel rule as the parallel supported either side of the vice to bring it to the required height. In this pic I've got it sloping to do the taper on a 1/16" wide gib headed key hence the 1/8" drill at one end.

[krv3000]

hi well ther is a nuther way you can by them or mack your own for free i no them as spring parallels sum cale them wavey parallelsther normaly 1mm thick the free ones are made of the metel banding that gose arawnd packing crates i have seen this stuff in 20mm thick strips and 50mm strips just bend it to form a wave one of the old boys at work use old band saw blades with the teeth grawnd off

[Lew_Merrick_PE]

It sounds good, as the setup is admittedly hard to hold.  Pictures would help though, as I can't quite envision what you're describing.

Sparky -- My vise & parallels are 6 inches long.  My widest parallel is 1.500 inches.  So, I take a piece of bar that is (say) .750 X 1.250 X 6.00 long and drill and tap three (call them) .1900-32UNF (#10-32) holes such that two are .200 from one longitudinal edge spaced at 5 inches centrally symmetrical and the third .200 from the other longitudinal edge on the centerline.  I fit #10-32 hex head cap screws that have had their heads turned to a slightly spherical radius (call it SR2.00 inches).  I now have an adjustable "tripod" that my 1.500 X 6 inch parallel can sit on whilst I have hands free to adjust and "fit" the part I am cutting off.

[sparky961]

Perfect, I think I got it now, thanks.

[vtsteam]

hi well ther is a nuther way you can by them or mack your own for free i no them as spring parallels sum cale them wavey parallelsther normaly 1mm thick the free ones are made of the metel banding that gose arawnd packing crates i have seen this stuff in 20mm thick strips and 50mm strips just bend it to form a wave one of the old boys at work use old band saw blades with the teeth grawnd off

I was hunting for a use for my old 1-1/4" band sawmill blades. Thanks, Bob!

[Stilldrillin]

Most of my working lifetime, was spent, milling. I never, used purpose made parallels........

I used lengths of key steel , of various cross sections. Also, many miles of "Bob's", steel banding.

When I retired, several yards of the material retired with me. Still have a few feet left. 

David D

[Lew_Merrick_PE]

DavidD -- As an apprentice, I made my own set of parallels.  That was one of the check-list items in those days.  It was my introduction to using a surface grinder.  Over the years that I worked on contract in various and widely spaced shops, many of that "set" sprouted feed and I broke down and bought a set from the widow of a colleague.  That is supplemented by several matched pairs of custom parallels made for a specific purpose.

I also have two sets of adjustable parallels.  The first set I had were made by me, but this disappeared in a move.  I find it interesting when I see people working on jobs that, had they a second set of adjustable parallels, would be much simpler to set-up.

[awemawson]

Very few jobs in a hobby workshop need any more accuracy in a parallel than can be got from cold rolled stock cut to length.

OK there are times when you do, but they are rare as cold rolled stock is amazingly accurate over a shortish (6" or so) length.

[CrazyModder]

Getting a bit off topic, but I also hear that dismantling bearings yields very accurate spacers...

[vtsteam]

Wrist pins are pretty useful, I find. Also machinery collars.

[Lew_Merrick_PE]

Very few jobs in a hobby workshop need any more accuracy in a parallel than can be got from cold rolled stock cut to length.

OK there are times when you do, but they are rare as cold rolled stock is amazingly accurate over a shortish (6" or so) length.

Andrew -- I am not disagreeing.  I was merely using my equipment as an example.  It is not uncommon for me to have to deliver parts that are made to +/-.0005 in (+/-0.013 mm) tolerances.  Typical CRS bar will be +/-.0005 in over a 6 inch length -- good enough for most home shop uses.

You just have not lived until you have had parts you made go through a NASA or military inspection program!