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View Full Version : Are homemade parallels a possibility?



JimDobson
11-07-2006, 06:50 PM
Are making homemade parallels on a mini mill a possibility or are they something that must be purchased ?

BillH
11-07-2006, 06:53 PM
mill 2 of them side by side, they will be identical in height as long as mill is trammed.

Doc Nickel
11-07-2006, 07:04 PM
Depends on how accurate you want or need them.

I know that, with a careful setup and sharp tools on my mill (import Bridgy clone) I could mill (not grind) two bars of off-the-shelf mild steel into parallels accurate to probably .001", easy.

Problem is, .001 isn't all that accurate for a decent set of parallels, and being soft mild steel, they'd go out of whack in short order.

For one-offs or temporary work, as long as you're "only" working to a thou or two, homebrew parallels are fine. I've frequently used two strips of 1"x1/4" aluminum bar, with no more preparation than hacksawing to length and a quick rub with a file to remove burrs.

Doc.

Tin Falcon
11-07-2006, 07:13 PM
Jim:
"propper" parralels are made in pairs and the edges are ground on a surface grinder. I picked up a decent set for the mini mill at kits Idustrial in Michigan. That being said and knowing you are on the far side of the earth and on a budget I have used pieces of packing strap as thin parrallels with good succes. You could aslo get ground flat stock and cut pieces with a fiber disk or hack saw this should be available from your indusrial supplier. Enco for example has O-1 1/32" x 1/2" x 18" long for $6 US you can get two 4" pair out of a piece the width tolerance is -0 +.0005" 1" wide is $9.50.
Regards
Tin

John Stevenson
11-07-2006, 08:16 PM
Shouldn't be any reason why not.
If they are settled down well in the vise and a cut is taken across the faces in one go then they should be better than a thou which for most uses is enough.

Tin has suggested getting some ground flat stock and cutting lengths up which is also a god tip.

I have a load of just ordinary mild steel packings that have been ground down on a surface grinder to just under stock size and paired up.
These are ideal when holding work the same size as the packings as you know that the packing won't trap and hold the work off.

I personally can't see why commercial packings HAVE to be a dead size, slip blocks yes, packings, no.

Then comes the problem ? [ is it ? ] that home made packings are soft, so what, if they get a ding you can still stone it out but if you happen to catch one with a cutter, and don't say it doesn't happen, you get a track in the packing.

With hardened packings that will cost you the cutter.

Vice jaws can also double up as packings and it's handy to have a small step in the jaws to hold thin work in the flat plane but just above the top of the vise.
Making spare jaws of of stock mild steel, clamping into position and them milling a shape out into the jaw itself is also a good move to hold delicate or weird shaped work.
It's only like using soft jaws in a chuck anyway.

.

mochinist
11-07-2006, 08:40 PM
I take it a packing is a parrallel?

Your Old Dog
11-07-2006, 09:43 PM
I just got a set from enco for something like $24.00 and free shipping. they'll likely do all I need.

Rich Carlstedt
11-07-2006, 09:44 PM
Yes,,packings are parrallels.
I have a whole collection of parrallels
Commercial ones ..hardened and ground.
Home made ones..from
............... Starritt Stock
...............Aluminum bars
...............Precision ground tool bits ie. 1/2x1/2, 3/4x3/4 etc
...............Thin ones ground from Used bandsaw blades
...............bits and pieces.

Also have on hand many pairs of Cut-off (parting off) blades.
( these are cheap at industrial supplies as most have gone to carbide.
The are very good to have in matched pairs..[1/2 to 1 1/4"]
Make sure they are ground, some cheap ones have rounded edges..
another benefit, the T shaped ones stand very well when upside down)
Rich

JimDobson
11-07-2006, 10:54 PM
Thanks guys for all the replies.

Carld
11-07-2006, 10:56 PM
You can make parallel's out of most anything, brass, aluminum, steel. I use cold roll bar stock a lot of times. If you are not doing precision work they are ok. If you finish them in a mill the hardest thing is to get the two machined sides parallel when you hold them in a vise. If you can hold them down on the table with toe clamps it is better. Use a flycutter to get a nice smooth finish. If you have a surface grinder then you grind them in pairs. I have sets I have bought and several I made out of tool steel bars. Key stock makes good parallel's. I also use key stock for parallel's on a press. Lots of different size key stock in 6" lengths is very handy. I'm talking from 1/4" to 2" or 3" here. Of course the larger sizes are longer.

wbleeker
11-08-2006, 01:08 AM
Jim,
Hare and Forbes are having their annual sale this weekend have a look at their catalogue at www.machineryhouse.com.au they might have something on special that suits you I think they take 10% off everything.If you haven't already got one you can order one of their catalogues at their website as well.
Will