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View Full Version : Possible to shorten parallels? If so, how?



Bolster
01-04-2010, 03:44 PM
I got a deal on a 20-pc set of hardened 6" parallels. I'll use them as-is if I must, but I have a 4" GMT vise. Is there any cost-effective way of cutting down hardened parallels from 6" to 4" that can be done in the home shop? Or should I repurchase 4" parallels instead? (I am having a hard time finding 4" parallels, and the ones sold by Enco are of terrible quality.)

RKW
01-04-2010, 03:48 PM
Use a cut-off wheel. If you do it incrementally and keep it cool you won't anneal them. You can clean/square up the cut on a grinder afterwards.

Carld
01-04-2010, 03:53 PM
What's wrong with having 1" hanging out each side? I have that on one vise I have and it's no problem. If I want them even on one side I slide them over.

When I was working, now retired, we would buy tool steel stock and cut parallels out of it and grind the two edges used to support the work. I have several different lengths, widths, and thicknesses of parallels for that reason as well as the complete sets.

Alistair Hosie
01-04-2010, 04:27 PM
I agree why shorten them you might live to regret it!You never know what life has to offer you may get a bigger vice in the future.Alistair

daveo
01-04-2010, 05:40 PM
I use a 6 inch set in a 2 inch vise.....

Pete F
01-04-2010, 05:46 PM
Yup. Me too, on a 3" vice. Sometimes directly on the table, too. I don't think I've ever thought about them being too long. I could see finding them too short.

-Pete

oldtiffie
01-04-2010, 05:59 PM
I got a deal on a 20-pc set of hardened 6" parallels. I'll use them as-is if I must, but I have a 4" GMT vise. Is there any cost-effective way of cutting down hardened parallels from 6" to 4" that can be done in the home shop? Or should I repurchase 4" parallels instead? (I am having a hard time finding 4" parallels, and the ones sold by Enco are of terrible quality.)

Why bother?

If you cut them they will need to be (re)surface ground as pairs or sets.

The base of the vise on which the parallel strips (or anything else) rests is rarely the width that is that same as the length of the vice jaws.

http://i200.photobucket.com/albums/aa294/oldtiffie/Vise/Vise7.jpg

One exception is the classic screw-less tool-makers vise.

http://i200.photobucket.com/albums/aa294/oldtiffie/Vise/Vise2.jpg

luthor
01-04-2010, 06:04 PM
Hey Tiffe, I like those toolmakers vices, especially the sine vice, are they from Hare and Forbes?

Bolster
01-04-2010, 06:36 PM
Well, to answer all the questions about "Why?" in one fell swoop:

I would like one pair of parallels that DON'T stick out of my 4" vise. I already have plenty that do. I find parallels sticking out, to be in the way. I suppose that's why people don't use 12" or 24" parallels in their 6" vises.

However, if they must be re-surface ground, that's a huge hassle.

danlb
01-04-2010, 07:08 PM
I've cut them with a 4x6 band saw. It probably was not good for the saw, but it did work. A quick pass on the grinder cleaned up the ends. Not sure why I'd have to re-grind them after cutting a pair in half. ???

I have a 2 inch vise on my micro mill, and sometimes the extra just gets in the way, especially when you want an irregular part to hang down on the side of the vise away from the mill's column.

Daniel

Fasttrack
01-04-2010, 07:18 PM
Well, to answer all the questions about "Why?" in one fell swoop:

I would like one pair of parallels that DON'T stick out of my 4" vise. I already have plenty that do. I find parallels sticking out, to be in the way. I suppose that's why people don't use 12" or 24" parallels in their 6" vises.

However, if they must be re-surface ground, that's a huge hassle.


No ... they were talking about grinding the edges after cutting. The important surfaces are unaffected by cutting off the "excess", if you decide you want to cut them. If they are too hard for a bandsaw (they could be ductile cast iron, although hardened steel is much more likely) then use an angle grinder with a cut off wheel. Keep things nice and cool - you might even jerry-rig a coolant system to keep water flowing. Then you can take them to a bench grinder and clean up any burrs. Grind a little "chamfer" on the top and bottom corners on either side so you are assured that there aren't any burrs, etc that could make them sit in the vise funny.

Boucher
01-04-2010, 07:31 PM
If I wanted them shorter I would clamp them in pairs and cut them to length in the 14" abrasive cutoff saw. One end that is not perfect is not going to hurt anything. They will be matched pretty close.

gnm109
01-04-2010, 07:47 PM
I've cut them with a 4x6 band saw. It probably was not good for the saw, but it did work. A quick pass on the grinder cleaned up the ends. Not sure why I'd have to re-grind them after cutting a pair in half. ???

I have a 2 inch vise on my micro mill, and sometimes the extra just gets in the way, especially when you want an irregular part to hang down on the side of the vise away from the mill's column.

Daniel


Wouldn't you have to grind the cut ends to make them square once again?....unless it doesn't matter.

Edit. Just saw the post above. No problem.

Steve Seebold
01-04-2010, 07:52 PM
Check with Little Machine Shop.com I got a set of parallels 3 inches long for about $30.00

RKW
01-04-2010, 08:11 PM
It is the age-old problem with many forums such as this :confused: You simply stated you wanted 4" parallels and how to cut what you had, not whether or not it should be done. Parallel sets aren't that expensive so if you have to have two then so be it, but you will also have the custom 4" set you wanted. Advice and suggestions are great but you did ask a very specific question.



Well, to answer all the questions about "Why?" in one fell swoop:

I would like one pair of parallels that DON'T stick out of my 4" vise. I already have plenty that do. I find parallels sticking out, to be in the way. I suppose that's why people don't use 12" or 24" parallels in their 6" vises.

However, if they must be re-surface ground, that's a huge hassle.

hojpoj
01-04-2010, 08:21 PM
I agree why shorten them you might live to regret it!You never know what life has to offer you may get a bigger vice in the future.Alistair

Like alchoholism or meth addiction?

Oh wait, those are still cheaper than this hobby :p

oldtiffie
01-04-2010, 08:26 PM
Hey Tiffe, I like those toolmakers vices, especially the sine vice, are they from Hare and Forbes?
Hi Luthor.

The "plain" vice as from H&F:
https://www.machineryhouse.com.au/Toolmakers-Vice

The "Sine" vice was from the US - either of these - forget which:
http://littlemachineshop.com/products/product_view.php?ProductID=1756&category=

http://www.cdcotools.com/item.php?itemid=26

Accuracy is superb:
http://i200.photobucket.com/albums/aa294/oldtiffie/Vise/Vise1.jpg

Note: 0.005/100 = 0.00005/1 = 0.00005" (ie "half a tenth") per inch

I haven't tested it quite that close but I have no reason to think that its not true as I was working in "tenths".

Note that with these vices (UK and AU) - vises (USA) - there is no moving vice up-lift problem/s as there is with most "conventional" vices.

Further, you can "roll them over" onto their back or sides or end and still maintain "squareness" accuracy.

But frankly I never use the sine vice as such as using slip-guages is expensive and a PITA mostly.

I prefer to use the tool-makers vice with a 0.10 degree (6 arc minutes = 0.00175"/inch) as that does for most stuff on the mills. Anything better, I will use the sine vice or the sine magnetic chuck on the grinders.

For most work, I will opt for this:
http://i200.photobucket.com/albums/aa294/oldtiffie/Seig_X3_mill/SeigX3_15.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Seig_X3_mill/SeigX3_16.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Seig_X3_mill/SeigX3_18.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Seig_X3_mill/SeigX3_19.jpg

I bought the the digital bevel guage at H&F (only about AU$30 ~ US$27) at H&F but can't find it in the on-line catalogue.

http://i200.photobucket.com/albums/aa294/oldtiffie/Seig_X3_mill/SeigX3_20.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Seig_X3_mill/SeigX3_21.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Seig_X3_mill/SeigX3_23.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Seig_X3_mill/SeigX3_24.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Seig_X3_mill/SeigX3_25.jpg

I bought the the digital bevel guage at H&F (only about AU$30 ~ US$27) at H&F but can't find it in the on-line catalogue.

I made mistake in buying the 7" x 5" tilting angle plate (Apex - Mordialloc) as it was too small. I bought a larger 7" x 10" one later - much better.

I just do not like using the ordinary type of vice on my mills as I prefer to bolt a job straight onto the mill table or an angle plate.

The normal run of the mill (sorry - not) machine vices are a poor replacement for a mill table.

I went to a fair bit of trouble to square-up/restore my angle plates (fixed and tilting) some time ago.

I also use my "cylinder master squares" a lot too.

http://i200.photobucket.com/albums/aa294/oldtiffie/Master%20squares/Squaring1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Master%20squares/Squaring2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Master%20squares/Squaring3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Master%20squares/Squaring4.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Master%20squares/Squaring5.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Master%20squares/Squaring6.jpg

It is quite possible to counter "moving jaw up-lift" and to make a cheap; vice perform quite well:

http://i200.photobucket.com/albums/aa294/oldtiffie/Vise/Vyce_clamp1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Vise/Vyce_clamp2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Vise/Vyce_clamp3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Vise/Vyce_clamp4.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Vise/Vyce_clamp5.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Vise/Vyce_clamp6.jpg

Note:
None of this applies to machine "hoggers and floggers" (aka "wankers" - aka "Tossers" in the UK) in a HSM environment.

http://en.wikipedia.org/wiki/Wanker

And for those who think that there are no wankers in the USA - have I got news for you!!!:
http://en.wikipedia.org/wiki/Wankers_Corner,_Oregon

The Fixer
01-04-2010, 08:54 PM
I've cut them with a 5" zip cut lotsa times no problemo. It ain't rocket science, just touch the ends up on the grinder. No need to regrind the surfaces as has been suggested.

darryl
01-04-2010, 09:03 PM
Think of it another way- once you have those 6 inch parallels cut down using a cutting disc, you'll have a pair of 4 inch ones and a pair of 2 inch ones. If you want the length to match and be an exact number, say 4.000, you'll have to do some careful work. I don't think that's what you want though- you simply want them shorter.

Cutoff disc is the way to do it. I would score them all around, making sure the score marks line up, then just keep turning them to deepen the cut until it's so close, then just snap them and clean up on the grinder. Cut a bit on one, put it down, cut on the other one, swap again, cut a bit- etc. That way they won't overheat, and you'll feel how hot they're getting. No need to quench, no need to rush.

I built myself a machine to spin a cutoff disc- two separate discs actually, one for stainless and one for everything else. It's got a bit of a table to support the workpiece and that's about it. No vise, nothing swings or chops- you bring the material to it by hand and feel the heat as it's being made. I use it to cut music wire, drill rod, hss cutting tools, hard bolts, - so handy to have. Washing machine motor runs it, just like my drum sander. Oh, yeah, the drum sander- just the thing to clean up the ends and debur after cutting off.

RKW
01-04-2010, 09:04 PM
Nope, Chi & Com! ;)


Hey Tiffe, I like those toolmakers vices, especially the sine vice, are they from Hare and Forbes?

oldtiffie
01-04-2010, 10:45 PM
Or Yin and Yang?

http://en.wikipedia.org/wiki/Yin_and_yang

Bolster
01-06-2010, 05:11 PM
THANKS for all the responses. Including RKW, who gets a gold star for his insightful comment!!

OK, looks like the way forward is an abrasive saw with coolant.

Now, this next question is probably insanely wacky, stupid, ill-conceived, etc., but:

I happen to own an MK-diamond tile saw that has a 10" diamond blade in it, and loads of cooling (sprays all over the place when cutting!) I'm looking at that thinking, hmm, it has a sliding table, coolant, and a diamond blade...

...but that's insane, right? Nobody cuts hardened steel with a diamond blade....DO THEY? The only reason I'm even allowing this to cross my mind is that the saw is due for a new blade soon, and I'll have this old blade on its last legs...

...Somebody tell me I'm insane and I'll stop thinking about it.

EDIT: More insanity: what if I got a metal cutting abrasive blade and put it on the tile saw??

Carld
01-06-2010, 05:16 PM
The general opinion is steel kills a diamond wheel. Try it and see if it does and let us know.

darryl
01-06-2010, 09:11 PM
I'd like to understand more myself about the effects of diamond on steel. If as has been suggested, heat is what makes the combination of steel and diamond a problem, then the real test would be to keep the heat down. Constant cooling and lower speeds should be able to keep things under control then.

How fast does the blade turn on a tile saw? If not too fast, and you apply a constant water spray, it could be ok. Keep the feed rate low as well, basically just use less pressure against the parallels when cutting them.

Have you got a piece of waste tile? If so, make a cut on it and note the speed at which is goes and try to get a feel of how much that loads the saw down. Then try to cut the parallels, keeping the loading about the same or less. If it seems to take forever to cut the parallels, go back and make another trial cut on the tile. If that cuts the same as it did before, I might suggest that you haven't toasted the diamond wheel, and also that you could continue to cut the steel- just take your time and don't force it. If the cutting goes too slow, the tendency will be to use more pressure. Then there will be too much localized heat generated, and you'll damage the wheel. You'd have to resist the urge to force it.

I have a 2 inch diameter diamond disc that I run at 3600 rpm, and I sharpen carbide and hss on it all the time. It doesn't appear that I've lost any diamond since it continues to cut about the same as it ever did. I don't use coolant on that one, but as you can imagine, because the diameter is so small, the speed of the diamond against the steel is low and it survives.

By the way, this disc is something I cut out of a diamond coated plate that's 1/4 inch thick. It was only 2 inches wide, so that set the size of the disc. As such it's very rigid an so doesn't have any tendency to vibrate against the tool I'm sharpening. As such, momentary contact pressures are kept fairly consistent, and I can easily control the piece I'm grinding on. That again helps to prevent minute hot spots.

If you look at the diamond coated sticks, etc- what are they recommended for? The reason you can use them on steel is that you can't move them fast enough against the steel to damage either the steel or the diamond.

That's the way I see it anyway. It has worked for me in my shop. I don't have and have never tried a large diameter diamond coated disc, so I haven't had the experience of it going bad. It will be interesting to hear of your experience with the tile saw.

I like the option of putting a metal cutoff blade on the tile saw. Basically then, it's a metal cutting radial arm saw. I can't see anything wrong with that. Again, I don't know how fast a tile saw blade rotates, and how much power it has, but that's what's going to set the speed at which you can cut steel on it. If anything, it's possible contamination of the tile that I would be worrying about. If there's steel particles wanting to come off the machine and go through the tile, that could be a problem. Of course, since that's a water spraying everywhere type of machine, steel particles would be tending to rust wherever they've become lodged- could be a little messy, could discolor future tile cuttings-

Carld
01-06-2010, 09:15 PM
It's my understanding that the heat melts the steel onto the diamond face and clogs it up. Using it slow and wet may be ok, I don't know.

Mcgyver
01-06-2010, 09:17 PM
I'd like to understand more myself about the effects of diamond on steel. If as has been suggested, heat is what makes the combination of steel and diamond a problem, then the real test would be to keep the heat down. Constant cooling and lower speeds should be able to keep things under control then.
.

my understanding is its the temperature where one molecule meets another, not heat that lets the carbon be absorbed. The single biggest factor to that temp is cutting speed so running very slowly should work...while coolant takes away heat i don't it has a huge affect on the temp at the point where the cut is being made

darryl
01-06-2010, 10:25 PM
Here's a few pix of my cutoff saw. You might recognize some of the parts- on the right is a handle off the milling machine, on the left is a washing machine motor, holding it all together is some mdf, and as it's a desktop type thing, it's sitting on a stand of some kind. http://www.glacern.net/free_photo_upload/cut-off%20saw.jpg

The top picture shows it tilted mostly backwards for use of the bottom wheel. The next pic shows it tilted forwards for use of the upper wheel. For some reason I don't have the table mounted in front of that wheel- I think I took it off to make it easier to cut some sheet stainless for something.

http://www.glacern.net/free_photo_upload/cut-off%20saw%20leaned%20forward.jpg

The function of the handwheel is to allow this tilting then secure the 'head' in position. The top disc is for cutting stainless, and the bottom one is what was called a 'superdisc'. Cuts on both sides and the edge. I use it for shaping and whatever else- dressing the ends of a just-cut piece, for instance. With pressure against both sides, the disc stays centered.

I used the flash to take this next picture to hopefully show the belt path, though I guess that would be self-explanatory. That's an aluminum pulley on the motor shaft, and two pvc pulleys on the separate arbors which mount the discs. I chose this way to mount the discs to leave as much room to either side as possible to swing a workpiece without running into a belt or a turning shaft.

http://www.glacern.net/free_photo_upload/cut-off%20saw%20motor%20and%20belt%20detail.jpg

There's a few things which aren't ideal- the first one is the lack of the table in front of the upper disc- I must put that back on for safety, unless I really want to lean into it one day and cut my head open. Another safety related item is the flammability of the mdf. I haven't had a problem with sparks setting it on fire, but it could happen. A metal shield inside would be a good idea. Power-wise the half horse motor is enough since I can easily heat whatever I'm cutting to the point where I can't hold it anymore. That's too fast to cut anyway if I'm trying to preserve any heat treatment on a workpiece I'm cutting.

The belt is from a small appliance of some kind- I don't actually know what it fit originally. I just bought it because it was what I wanted to use for this project- compact and efficient. I have never replaced the belt, nor had to replace or remachine the pulleys. This machine is about ten years old and I use it all the time- same for the drum sander which you can almost see to the right of it. The pvc pulleys have proven to be remarkably durable. When first made, the top of the belt sat level with the edges of the pulley- now they're just a tad low in the groove. I have only adjusted the tension once, and that's when I replaced the worn-out bottom disc.

Bolster
01-06-2010, 10:30 PM
D*mn that's cool, I really like it. (I love owner-made machines in general.) A real man's machine that can kill you easy if you're not careful.

Bolster
01-06-2010, 10:31 PM
How fast does the blade turn on a tile saw? If not too fast, and you apply a constant water spray, it could be ok.

The motor runs 3450, and the blade runs 3105 RPM.

So, are most cutoff discs OK to run wet, or am I looking for a special wet-rated disc?

lazlo
01-06-2010, 10:40 PM
Here's a few pix of my cutoff saw.

Very nice!

By the way, diamond cuts steel just fine. The life of the abrasive will be shortened if the temperature rises above some set amount (800* F, IIRC), which is why the Glendo diamond sharpening wheels rotate so slowly (300 RPM). The sharpening wheel in the Darex drill grinders is diamond as well.

darryl
01-07-2010, 01:56 AM
Thanks for the kudos on my cutoff saw. I'd take a bow and send my picture in, but then you'd see the vertical gash on my forehead :) Just kidding.

Ok, 3100 rpm on the tile saw blade, yeah, I'd say too fast for diamond on steel, but it's your experiment. Keep the coolant flowing and the feed light- see what happens. Better advice is probably to just install a proper cutoff blade on it and be good to go. Wet or dry- I can't imagine that water would hurt the blade- good question though. I can't think of any bonding agent that would be good enough to hold the grit on that would be affected by water. Same for the disc itself.