PDA

View Full Version : Who can cut mark out and accurately cut with a hacksaw?







Grahame Collins
12th December 2013, 08:33 PM
Rather the hijack the thread below ,I am curious to know how many members know how to accurately mark out stock and cut with a hacksaw.

If there are those who wish to know ,perhaps some of us old hands could offer a bit of a tutorial.

Same thing for marking out and drilling accurate holes with a drillpress.

As a metal shop teacher I would laugh at those who would take a length of 6mm round to be cut off in the bandsaw. While they were still thinking about it ,an experinced hand has the hacksaw out and zips through it off in moments.

scottyd
12th December 2013, 08:41 PM
As a metal shop teacher I would laugh at those who would take a length of 6mm round to be cut off in the bandsaw. While they were still thinking about it ,an experinced hand has the hacksaw out and zips through it off in moments.

I can top that, I had a student who asked to use a power hacksaw to cut a 1/8in brass round. Thats three and a bit strokes on a hacksaw, we tested it.

But great idea. I think going over getting the saw setup properly is something a number of newbies gloss over.

pipeclay
12th December 2013, 09:47 PM
I have no idea how to mark out for round stock apart from scribing a line.

For marking out for drilling I was taught if required, to mark out the hole position with lines intersecting,centre pop and then use dviders to scribe the hole diameter,then centre pop where it intersects the scribed lines,then when drilling see that the centre pops are split.

As you start check to see if the drill is centred to the pop marks if it favors one side get your centre punch an put a little groove opposite the side it favors,this generally causes the drill to track back on centre.

For cutting with the hacksaw a similar marking out process splitting centre pop marks work.

Bryan
12th December 2013, 10:11 PM
Does this count?

anglesmith
12th December 2013, 10:31 PM
Many a time as a apprentice at the Mortlake Gasworks I was sent to the store with a hacksaw to cut off what was require, some time 2"!. Today I think that most people's experience is with cheap hacksaw frames and cheap blades and don't think it is possible for ANYONE to cut accurately to a line with most of the frames on the market today! I have collection of Ding Dong frames (first made in the thirties) and some very solid file handle style 12" frames from the early 1900s (German I think) They have a solid square head on each end with slots and cross holes that a cut down 2" jolt head nail fits perfectly!! Though I confess that a few weeks ago I bought a Bahco 325 hacksaw at the market for $10 ($60 or so new on eBay) and it seems to be very good. So RULE No1 is you can't cut accurately if you don't have a ridged hacksaw frame. I think rule No 2 for me is to have several saws ready to go so that the right blade can be selected to the task in hand. BTW who has ever used 14 tooth blades in a hand frame, they use to be available ?! Graeme

Michael G
13th December 2013, 06:58 AM
I have a Bahco 325 and would agree that it is a wonderfully rigid saw possibly the best available (new) these days and probably the best I'll ever use. $10 is a steal.

One of the secrets to getting a good result is having good blade tension. Especially with cheaper tubular saws slackening off the blade after use is essential as the tension can be too much for the tube and it will (over time) bend enough to reduce the tension. The Bahco doesn't seem to need this (and the tensioning arrangement is such that you can't). I've been able to cut a lot straighter since getting rid of the tubular and using a rigid frame saw.

Another tip I've discovered is to use a dot of trefolex on the blade as a lubricant. Just like using it for tapping, it makes the job a lot easier

Michael

bollie7
13th December 2013, 08:11 AM
BTW who has ever used 14 tooth blades in a hand frame, they use to be available ?! Graeme

:thumbup: I've got some. A couple of packets I bought at a swap meet for $0.50 each years ago. Starrett I think (they are painted yellow) When I did my apprenticeship we were taught that there wre 3 grades - 32, 24 & 18. No mention of a 14 so I didn't know they even existed until I got these ones. In fact, when I bought them, I bought 12 boxes of what I thought were 32, 24 & 18. There were 2 boxes of 14's in there. I don't think I have actually used one of them yet.

As others have said, a good frame and, IMO, a good quality blade are the key to cutting straight. I also bought some boxes of blades at another swap meet years ago. It says "eclipse - made in NZ) on the blades. I think that rather than being "low carbon" that they are actually "no carbon". Crappiest hacksaw blade I have ever used. About all they are good for is cutting PVC pipe. Which is all I use them for. They are also very flexible. I can bend one well past 90 deg before it will break.
bollie7

wheelinround
13th December 2013, 09:06 AM
Its always nice to see an old hand grab the steel he needs a quick scribe then the hacksaw a couple of stroke walk to the grinder/llinisher and finish off to the line.

Then there is the fellow who takes 3 hours to set up to drill 1 hole


Me it depends on the need of the end product marking out depends on the need of the job as does cutting, files etc to the finish line.:B

DSEL74
13th December 2013, 09:25 AM
I think marking blue and a scribe to get an accurate line and not a line drawn on with a marker pen. Unless you scribe down the marker pen line.

Use of vernier height gauges and surface plates can help with marking out also. Although none of this helps me cut a straight line. Reading what others have posted above may be part of my troubles, lack of practise the other factor. I will go and loosen the blades off on my two tubular hacksaws while they are not being used now.

Bryan
13th December 2013, 11:12 AM
I reckon my single biggest mistake used to be pressing too hard, usually due to a dull blade and fatigue/impatience.

Oldneweng
13th December 2013, 06:40 PM
In answer to the question, not me. I don't like hacksaws and I will only use one if I have too. I cut myself fairly badly when a youngster by having my fingers underneath the blade when it broke thru. It would be interesting to try a really good frame but I doubt I would use it any more. I have an Eclipse I think and a real cheapy. The truth is that due to health reasons I find it difficult to spend much time doing physical work of this nature which is why I use machines as much as I can.

Dean

Grahame Collins
13th December 2013, 08:18 PM
Hi everyone
The following works well for light rectangle/square flat bar or box section.

I am only inclined to use a hacksaw if the cut is below 20mm solid.I have dengue fever and the after effects in the form of a severe arthritic pain is starting to catch up to me.
For the lighter stuff I can still cut a piece of 25 x25mm box section pretty accurately.

Any former wood butchers that have come over from the dark side will know the technique.When starting a cut, start with a little cut on each corner and run the blade against your finger initially to align those corner cuts and wallah! a straight line. Basically, you prep the line to be cut.The position of the cut is found by aligning the set of the teeth against the line.Even the most award of us should be able to get within a 1/4 of a millimeter.
I have gone back and read some old sets of instructions on hack sawing techniques and the bit about the grooves never gets a mention .

If this is done on all four corners you end up by having some straight lines /grooves between all 4 corner cuts. This is part of the technique as the saw blade will follow the line of a least resistance -the grooves.

Given you have marked it out square and the that you have a half decent hacksaw frame with the correct TPI blades you should have no trouble. For making out I favor the tiny nibbled ink markers that draw a real skinny line about a millimeter or so.My favorite is a real Lenox hacksaw frame from when Lenox was a good brand.I still have stash of Lenox blades as well. While I think to mention it ,don't skimp on those blades,Use a good name brand and it will given much better results than the carp ones.

Always use 2 hands and at the speed of roughly 1 stroke per second on the "power" cuts. A bit of lube is a good thing, as well.

Dsel74, Top tip .Try to remember this guys as the tension will bend even a good hacksaw frame - always back off the tension for storage .

Remember

1.Corner cuts,
2. Starter lines grooves and
3.Sharp tensioned blades of the right type and TPI to suit the metal.
4.Use 2 hands
5.Back off stroke pressure and speed near the completion of the cut

I hope it helps someone

Grahame

Grahame Collins
13th December 2013, 08:31 PM
I have no idea how to mark out for round stock apart from scribing a line.

For marking out for drilling I was taught if required, to mark out the hole position with lines intersecting,centre pop and then use dviders to scribe the hole diameter,then centre pop where it intersects the scribed lines,then when drilling see that the centre pops are split.

As you start check to see if the drill is centred to the pop marks if it favors one side get your centre punch an put a little groove opposite the side it favors,this generally causes the drill to track back on centre.

For cutting with the hacksaw a similar marking out process splitting centre pop marks work.

Same here ! I watched and old tradie bring an 1 inch bit back on center using this technique. Centre popping is the devil. :((As I get older ,its harder and harder to see the true mark.I have a couple of sets of Chemist shop reading glasses around my w shop to help with this.

DSEL74
13th December 2013, 09:06 PM
I absolutely adore these really old hacksaws. Referred to as lancashire pattern hacksaws. They used to come in 2" increments I think it may have been 1". They went out of favour when the adjustable spine version came in as you only needed one frame for all blade sizes vs a separate saw for each blade.

http://t3.gstatic.com/images?q=tbn:ANd9GcRWcEiG34OdJ58_B5zz5gBlL4PJAuGfKLoqomPgv-RRTKiMp4Zohttp://www.classicboat.co.uk/wp-content/uploads/2012/09/1+lancs+hacksaw+robgates.jpghttp://p2.la-img.com/302/21388/7338240_1_l.jpg

Stustoys
13th December 2013, 09:28 PM
SAs I get older ,its harder and harder to see the true mark.
Hi Grahame,
You might find one of these handy

http://www.woodworkforums.com/f65/optical-centre-punch-simonl-155247/

Stuart

Steamwhisperer
13th December 2013, 10:02 PM
Hi Grahame,
You might find one of these handy

http://www.woodworkforums.com/f65/optical-centre-punch-simonl-155247/

Stuart

Just to let you know, I use it 'everytime' I mark something out.
Best thing I ever made.

Phil

Grahame Collins
14th December 2013, 06:19 AM
I have started one of those ages ago. I have yet to get some silver steel for the punch.
I guess I'd better finish it while I can still find my way to the lathe.

Grahame

Steamwhisperer
14th December 2013, 07:06 AM
I have started one of those ages ago. I have yet to get some silver steel for the punch.
I guess I'd better finish it while I can still find my way to the lathe.

Grahame

Hi Grahame,
what size silver steel are you after.
I still have some here left over.

Phil

Grahame Collins
17th December 2013, 07:24 AM
Hi Grahame,
what size silver steel are you after.
I still have some here left over.

Phil

hi Phil,
Your offer is very kind.
The Lucite rod I bought for the job is 13mm ,so guess that size or a big bigger would be just fine.
I have the brass for the base. I will PM you tonite.

Thanks Grahame

BaronJ
17th December 2013, 08:53 AM
I absolutely adore these really old hacksaws. Referred to as lancashire pattern hacksaws. They used to come in 2" increments I think it may have been 1". They went out of favour when the adjustable spine version came in as you only needed one frame for all blade sizes vs a separate saw for each blade.

http://t3.gstatic.com/images?q=tbn:ANd9GcRWcEiG34OdJ58_B5zz5gBlL4PJAuGfKLoqomPgv-RRTKiMp4Zohttp://www.classicboat.co.uk/wp-content/uploads/2012/09/1+lancs+hacksaw+robgates.jpghttp://p2.la-img.com/302/21388/7338240_1_l.jpg

One of my hacksaws is very similar to the third one down on the right of this picture. It originally belonged to my Granddad so its getting on a bit. The blade is quite a bit wider than the blades around nowadays. My normal use saw is a "Bacho" with a plastic coated frame.

Although I was taught to use a saw properly I do tend to be lazy and use my chop saw particularly if I want an accurate cut...

Steamwhisperer
22nd December 2013, 06:32 AM
hi Phil,
Your offer is very kind.
The Lucite rod I bought for the job is 13mm ,so guess that size or a big bigger would be just fine.
I have the brass for the base. I will PM you tonite.

Thanks Grahame

Hi Grahame,
are you going to turn the shank of the lucite down at all and leave a larger head?
If so, then you may need a smaller diameter piece of silver steel. I found I didn't need such a large head on the punch but the bigger head on the magnifier worked well.

Phil
298121 298122

Grahame Collins
22nd December 2013, 08:06 AM
My apologies Phil ,I completely forgot about PM -ing you.


I had not considered it, but now will as it obviously works. Its been that long it getting a roun- to- it.The lucite has sat on the desk near the computer for 18 months.

Thank you for the pics - explains it all in a glance.

I suppose I have had the mind set of the shaft being the same as the lucite-.
The original diameter of your lucite- was it around 12-13mm >.That would make the silver steel shaft half of that. I understand that this is just to "pop" the mark observed and centered by the optical bit.
Some of course not be able to separate "pop" from wallop.

Thanks

Grahame

Steamwhisperer
22nd December 2013, 09:29 AM
My apologies Phil ,I completely forgot about PM -ing you.


I had not considered it, but now will as it obviously works. Its been that long it getting a roun- to- it.The lucite has sat on the desk near the computer for 18 months.

Thank you for the pics - explains it all in a glance.

I suppose I have had the mind set of the shaft being the same as the lucite-.
The original diameter of your lucite- was it around 12-13mm >.That would make the silver steel shaft half of that. I understand that this is just to "pop" the mark observed and centered by the optical bit.
Some of course not be able to separate "pop" from wallop.

Thanks

Grahame
No worries Grahame, at least I'm not the only one that forgets. :D
Mine is 3/4" oops, about 19mm and if I remember correctly the shank is about 10 mm so the ratios you mention are about right.
I use the smallest ball pein I have and as you say, it is just a 'pop', and 'then' you centre punch it.

Phil

Abratool
22nd December 2013, 01:26 PM
No worries Grahame, at least I'm not the only one that forgets. :D
Mine is 3/4" oops, about 19mm and if I remember correctly the shank is about 10 mm so the ratios you mention are about right.
I use the smallest ball pein I have and as you say, it is just a 'pop', and 'then' you centre punch it.

Phil

Phil
So the 10mm is 3/8" or .375" less a thou for clearance, after reaming to .375" dia?
All the best for Christmas, & thanks for your valuable input through the year.
regards
Bruce

Steamwhisperer
22nd December 2013, 04:59 PM
Phil
So the 10mm is 3/8" or .375" less a thou for clearance, after reaming to .375" dia?
All the best for Christmas, & thanks for your valuable input through the year.
regards
Bruce

Hi Bruce,
I used a piece of 3/8" silver steel and machined it down to 11/32" minus 0.001", I did the same on the shank of the optic.
I was able to do this as I happen to have a 11/32" reamer which worked perfectly.

Phil