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Hacksaw blade tension

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Terryd13/09/2011 13:35:08
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1946 forum posts
179 photos
Hi John C,
 
I agree with you entirely, specific tools for specific machines, all colour coded. I don't bother with my files these days but I still colour code the flutes of my drills which are kept in Beech blocks, Green for imperial, red for metric, blue for letter drills etc. I also rub white paint over the size stamp on each drill, then wipe off leaving a very readable deposit in the stamping.
 
Unfortunately dedicated practical subjects such as Metalwork and Woodwork were thrown out with the bathwater in the reorganisations and 'initiatives' of the 1980s. (my friend has a definition of 'initiative' - "an idea which didn't work last time" ) this was along with the 'initiative' that we no longer needed most manufacturing, as we were to be a 'Service Economy' i.e. banking and insurance - that was a good initiative, not.
 
However I see that the subject of 'Engineering' is making it's way back into the curriculum, not always mechanical but at least it's a start. And new machines are being to be installed in some schools so there is some hope for the future.
 
Best regards
 
 
Terry
DMB13/09/2011 23:11:01
1585 forum posts
1 photos
Hi Terryd,
 
I have also coloured the tops of the flutes of all drills and taps and a dab of colour on all dies, same side as size stamping. Funnily enough, my Metric gear has been coloured red same as you did. BA =white. ME32T=blue band. ME 40T=blue and yellow bands.
BSW=orange band. BSF =red and yellow bands. Brass 26T = yellow band.
Metric drills=red. No. series=green. Letter series= yellow. Fraction series unmarked.
When I get around to it, I will colour my Metric endmills and slotcutters red, leaving Imperial sizes unmarked.
Many moons ago, drills came chemically(?) blued with a silvery band on the shank where the size was clearly stamped. Now, metric drills come all over matt black, badly or illegibly stamped with sizes if stamped at all. Have the beancounters banned "quality"?
My back entrance gate, outhouse both have coloured padlocks, together with the 2 on my workshop door, all with matching coloured keys. So much quicker and more convenient.
Regards,
 
John
chris stephens14/09/2011 00:18:33
1049 forum posts
1 photos
Hi John,
Quality drills still come with a ground finish!
chriStephens
PS I forgot to mention, at a price but still worth having.
Stub Mandrel15/09/2011 22:12:15
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4318 forum posts
291 photos
1 articles
Do Proops still do a good deal on the yellow and green starret blades? I've just fitted my last one after years and they beat Eclipse, let alone the joke ones that most places sell.
 
Neil
alan frost16/09/2011 01:24:08
137 forum posts
3 photos
 
If you have n't come across this site b4 have a feast and read the article titles. I'd be surprised if you don't find something worth tasting.
 
The tensions quoted endorse JS's comments and I would certainly endorse his opinion on the tubular types although I suspect you'd have trouble hitting the cat judging by the way they saw-I do have one I keep with an abrafile blade in it. I use this for sawing curves which the tubular type are particularly adept at.
 
For most of us with 4X 6's the tension translates into as hard as you can tighten it unless you've got exceptionally strong wrists , which I would n't admit to if I were you. Makes people wonder how you spent your youth.
 
By the way among several mods to my 4X6 ,I added an old valve spring to the tensioner so the blade rides on spring tension (an easy 60 minute modification ) and my blades last a long while even when sawing up dubiously procured railway track -embryo anvils-(a severe test of man and machine I can assure you. . Rail track is much bigger than it looks from 10 feet up in a train compartment and bloody heavy. I actually got mine legally ,which I hate to admit , when they rebuilt the Alloa -Stirling line ., "Go down the yard and pick a few bits and I send a couple of my men to help you load it. Don't want you nicking bits when the trains are running, do we "  

Edited By alan frost on 16/09/2011 01:28:17

Edited By alan frost on 16/09/2011 01:35:24

Edited By alan frost on 16/09/2011 01:39:33

Mike16/09/2011 10:40:38
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713 forum posts
6 photos
Starrett are still very much in business, and you can buy direct from their website at
http://www.starrett.co.uk/shop/
No sign of the yellow and green blades Stub Mandrel mentions, but their bi-metal blades look good, and there is also very rigid looking hacksaw frame at a reasonable price.
Ian S C16/09/2011 10:41:39
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7468 forum posts
230 photos
When mums father came to NZ for a holiday in 1952 he bought some of his tools (he woukl have bought more but they exceded some weight limit), amoung bthem was a hacksaw bkade, "Elephant " brand I think, it is 1" wide with teeth on both sides, its had a fair bit of work over those years, and I don't think it was new when it came here. Its in our local museum now. They don't make them like that any more. Ian S C
John Stevenson16/09/2011 22:04:04
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5068 forum posts
3 photos
My experience with bandsaw blades took a leap up when i got involved in building a saw that was designed to cut the runner and riser pipes that come from the sea bed up to a drilling rig.
 
When a well is finished the big valve on the sea bed is closed and the pipes were blown off about 70 feet below the surface as the rigs can only lift 70 foot of string at a time.
 
However new regs introduced say all pipe has to be removed so then send an expanding tool down like a 3 fingered hone which grinds away as it opens up and severs the pipe just above the valve, quicker that submersibles trying to undo the flange. They then lift this pipe up to max hight and clamp it there.
 
two machines go into action, a big bandsaw that cut the top 70 foot off to go into a supply boat and below this a double ended core drill that belts a 4" hole thru from both sides for a pin to go in for the next lift.
This drill pile can be different sizes but usually the outer is 32" diameter and about 1"thick, inside this is a 24" pipe about 1 1/4" thick and inside this is an 18" pipe same thickness.
Between the two outer tubes they are filed with cement, not concrete and also in the pipe are butterfly clamps that are spring loaded to keep the pipes concentric whist the cement is poured.
For some reason these are hardened ?? and no one knows where they are when you are cutting.
 
The saw in question was fabricated out of 6" square stainless tube with a 1/2" wall thickness, plenty of gussets etc and carried a 2" wide blade 1 tpi, tipped and was powered by a 10 HP hydraulic motor [ no electric motors allowed on deck ]
 
We had a section of pipe specially made for us 8 feet long with 30 butterfly clamps fitted and marked, every test cut had to be thru a clamp. When we started off blade life was in minutes and we got Lennox out to assist.
 
first question they asked was how tight were we tightening the blade and the answer was we didn't know but we thought we were not over tightening it. They put their gauges on the blade and got us to tighten it up, gauges never moved.
We kept tightening and it still never moved and we ran out of adjustment.
 
All we were doing was bending the frame.! !
 
Back to the drawing board and the frame was stiffened up with side plates of stainless 6" x 1 1/2" this time we got a reading but it was far, far more than I would have tightened up, thing 3/4" drive socket with 5 foot of bar on it !!
 
Lennox were magnificent on this and first cuts were 1 hour 20 minutes and with a bit of tuning we got it down to just over the hour.
They came back with a 1 1/2" wide blade, vari tooth with tips on it the size of match heads. I laughed when I saw it and told the guy no was, on the blade we had we were loosing 10 or so tips per cut and one blade did 4 cuts and was scrap.
 
So we ran it, not our blade anyway and lost 2-3 teeth per cut, 7 to 8 cuts before it was scrap and cutting time down to 45 minutes.
They gave all the lad on the job a hacksaw and a load of blades, one lad didn't want his so I got two.
 
I asked about releasing tension and the Lennox guy just smiled and said if you have to release tension something isn't right.
 
Modern version of the original but not for runner and risers pipes.
 
http://www.youtube.com/watch?v=wHvJNHFqldQ
 
John S.
EtheAv8r16/09/2011 23:42:07
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111 forum posts
3 photos
Thanks John S for the pointer to the Lennox in your post above; as a result of which mine arrived today with 3 packs of blades.
 
However I must be wary as your posts keep costing me... time, effort and dosh and a huge (but fun in an odd sort of way) learning curve on several fronts, after all I was planning on just getting a smallish manual mill and ended up getting a KX3, and now I am fighting with DraftSight and Cut-2D in the hope of one day being able to pass a file to Mach3 and make something!
 
Edmund
 
PS I am not allowed to throw my Eclipse hack saw at the neighbours cats - even though they come in a poop all over my garden, so not quite sure what to do with it, seems a waste to just bin it!

Edited By EtheAv8r on 16/09/2011 23:42:22

alan frost16/09/2011 23:58:34
137 forum posts
3 photos
Put an abrafile in it and use it for curved cuts. The name Eclipse comes from the fact that they eclipse all others at sawing curves.
blowlamp17/09/2011 00:56:51
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1885 forum posts
111 photos
Posted by EtheAv8r on 16/09/2011 23:42:07:
... and now I am fighting with DraftSight and Cut-2D in the hope of one day being able to pass a file to Mach3 and make something!
 
Edmund
 
Edmund.
If you want a test file to cut on your mill, just let me know what you're after and I'll draw something up and generate some Mach3 compatible g-code for you to play with.
 
 
Martin.
Nicholas Farr17/09/2011 07:49:22
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3988 forum posts
1799 photos
Hi, well I've always tightend hacksaw blades up as tight as I can get them, and I've never slacked them off when not in use, I have never found a problem. IMO they should be at least tight enough, so there is minimal twist in the blade. In my experience I have found that the Eclipse all hard blades to be the best.
 
Eclipse blades can be obtained from Buck and Hickman and various other suppliers.
 
 
Regards Nick
 
P.S. no connection with Eclipse or Buck and Hickman
EtheAv8r17/09/2011 22:11:44
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111 forum posts
3 photos
Posted by blowlamp on 17/09/2011 00:56:51:
Posted by EtheAv8r on 16/09/2011 23:42:07:
... and now I am fighting with DraftSight and Cut-2D in the hope of one day being able to pass a file to Mach3 and make something!
 
Edmund
 
Edmund.
If you want a test file to cut on your mill, just let me know what you're after and I'll draw something up and generate some Mach3 compatible g-code for you to play with.
 
 
Martin.
Martin
 
That is very kind og you thank you. It is not that I have something specific I want or need to make - yet; it is a question of getting to grips with the various tools (hardware and software) and the work and process flows. I am making slow progress, but I am at out of the house on work days from 06:40 to 21:15 so only really have week-ends, which are filled with a lot of other stuff!
 
From December I will be switching to part time (3 days a week) working and will have a bit more time.
 
Edmund
Derrick Watson20/09/2011 21:44:16
18 forum posts
Been away from the forum for a couple of days.
 
Just wanted to say thanks for all the useful info. Alan - very nice website you listed - hadn't seen that before, lots of useful information and ideas for stuff to make.
 
Oddly enough, I do have a straight handled hacksaw (somewhere) but have always used my pistol grip one assuming it would be better - sounds like I should give it a go.
 
cheers, .d
Terryd20/09/2011 22:07:09
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1946 forum posts
179 photos
Hi Derrick,
 
I would certainly give the straight handled saw a go. With care and correct technique accuracy depends on the user not on the frame. To quote the old adage, "A bad workman blames his tools".  The straight handle allows a more delicate approach and more control of the blade.
 
I have used all sorts of frames, good, bad and mediocre, solid and tubular, and have managed to cut quickly and accurately with them all. The straight grip is just easier. 
 
Use the full length of blade, keep your strokes steady (about 1 per second), don't force the blade and envision where you want it to cut. The rest is just practice. Success is 30% skill, 30% technique. 30% observation, 9% perspiration and 1% equipment.  Without skill the most esoteric and expensive equipment is naught.
 
The blade should always slope downwards away from you i.e. the front of the blade lower than the handle.  The alternative is a recipe for disaster.  Inaccurate cuts and broken blades are the result.  The secret of the success with the hacksaw is patience.  As I taught my students "make haste slowly"
 
Regards
 
Terry

Edited By Terryd on 20/09/2011 22:17:22

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