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Hemingway Hacksaw

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David George 103/02/2019 17:04:46
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1197 forum posts
409 photos

Looking a very nice piece of work.

David

Mark Elen 108/02/2019 10:28:18
117 forum posts
201 photos

Hi David,

Many thanks for your kind comments.

I have got a bit more done in the last few days. The con rod is complete, I reamed out the 1/2" hole and bored out the 5/8"

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Then I decided to start work on the slide bar retainers. These took a bit of working out how to hold them as the castings were not square. I had to square up one side and make up a set of soft jaws to hold these whilst I worked on them.

The bosses for the screws didn't line up too well either. I decided to use the dro, line up centre on the raised portion on the back of the casting, then place the holes as best I could in the bosses.

The holes are correctly placed at 2" centres (50.8mm) but they don't line up in the bosses very well.

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Cheers

Mark

Mark Elen 110/02/2019 17:08:57
117 forum posts
201 photos

One of the things that I have not been looking forward to was machining the bow. I don’t know why now. I got stuck into it last night, doing the slides first, then today I have set it up on the angle plate and drilled the boss.

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Don’t look too closely at the spirit level on the square... I still need to level the mill.

Cheers

Mark

Mark Elen 111/02/2019 22:23:43
117 forum posts
201 photos

I got the hole drilled in the boss, then set back up on the table using the slide bar and clamps to hold the bow in correct alignment. I took really light cuts, because the bow is just hanging in free space.

I milled off the ends and the waste in the middle, made up the threaded adjuster, I need to mill half of the end off now and drill for the pin. I have marked up for the M5 screws to hold the blade, just need to drill and tap.

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I have had to go 'off piste' with the adjuster screw, putting a 120 degree cone on the end. The drawings/casting is a bit out. the boss should be 1" long, but just skimming the end square, left it 3/4". I drilled down 39mm, the drawings called for 1 3/8" (34.93mm) even with this adjustment, if I had left the adjuster square and drilled for the pin at 1/4" the blade would not have fitted.

At 1/4" from the tip of the cone, the blade should fit with a little slack.

Cheers

Mark.

Simon Birt18/02/2019 14:28:10
7 forum posts
3 photos

Just fell across this. I built one of these last year it was an interesting project. It marked my return to model engineering after a nearly 20 year gap. Not sure if you have done it yet but the fit between the saw casting bearing surfaces and the arm that it runs on needs to be on the tight side. Mine makes a bit of a clunk when cutting as it changes direction. On reflection I would machine it within a few thou and then hand fit until it just slide on the bar. It was surprising how it loosened up jouring the running in process.

I’m very please overall, it cuts very well and is still on the original blade after 6 months.

Simon

Simon Birt18/02/2019 14:53:47
7 forum posts
3 photos

Here is a picture

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not done it yet18/02/2019 16:14:44
4514 forum posts
16 photos

He he! If that pic is a recent one, you’ve not used it a lotsmiley_

Looks good, btw.

Simon Birt18/02/2019 17:54:27
7 forum posts
3 photos

It was taken after it was finished, it is now a bit less shiny, not sure if is appropriate to polish a hack saw.

Ruddxi14/09/2019 18:27:33
1 forum posts

I've decided im going to do this project myself and will be making an order very soon.

so i started searching for more info on the saw and found your build! very nicely done so far, and now i cant wait to get started myself!

Mark Elen 105/11/2019 18:52:36
117 forum posts
201 photos

Hi Folks,

Many thanks for your comments. I have had a bit of time off this build. Lost interest a bit, but recently got the urge back to continue.

I have got quite a bit done but had the odd issue. The first thing I did was to sort out the riser for the vice. I had drilled and bored out for the vice screw as one of the first jobs I started with. Needless to say, they were miles out. I ended up making an aluminium block that was a good tight fit in the slide way of the riser that I could use to pick up the edges with an edge finder.

Before doing that, I set the riser up in the vice and ran a DTI down the slide way. Once I had picked up the centre, I bored the handle end until I had taken out the error, it ended up ~14mm

The other end wasn’t as bad, I managed to set it up the same and a 10mm endmill sorted it out.

I had to adjust the vice screw to my new dimensions. As I want the vice to operate the ‘right’ way, I got set up and screwcut a 1/2” BSF Left Hand thread, finishing it off with a die.

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Next job was to set up and bore out the bottom brackets to 5/8”:

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Then I got set up to make the drive shaft. This calls for a piece of 1/2” bar to be turned down to 11mm. I ummed and aaared as to how to set this up, but ended up with a small chunk in the 3 jaw and a live centre at the other. The first skim cut showed the tailstock being out of alignment. I had nearly .4mm difference over 5”. There followed a round of adjust, skim, mic, repeat until I got it down to .04mm

Done, in the mill and slot cut for key, key made and in, finished:

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It ended up at 10.996mm one end and 10.992 the other. The hole in the gearbox is a touch under 11mm, as a piece of 11mm ground rod will not fit. (I bought it to save making this.....)

Cheers

Mark

Mark Elen 105/11/2019 18:57:20
117 forum posts
201 photos

Hi Simon,

Thanks for the info on the slide bar. Mine is too tight. I ended up making some shims out of 4 layers of tin foil to allow it to slide. It is still fairly tight though. I may need to revisit this before it is finished.

Cheers

Mark

Mark Elen 107/11/2019 18:58:56
117 forum posts
201 photos

I have tried....and failed to tap the vice slide. I bought a 1/2” BSF Left Hand HSS tap. I drilled out the cast iron to 11.1mm then had a real struggle to get the tap to start.

When it did, it felt like the tap was going to snap, so when it went ‘click’ I was fully expecting a tap in 2 bits. What I got was this:

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Needless to say... there were a few swear words issued. There was a few hours work in that piece.

I’m now busy making a new one out of a piece of 50mm square cast that I bought this week. I’m wondering if I need to drill it out to 11.3 or 11.5 before I have another go, although, this time there will be plenty of meat around the hole, I will mill it back once the hole is tapped.

Pointers would be appreciated

Cheers

Mark

not done it yet07/11/2019 19:19:42
4514 forum posts
16 photos

One tap? Taper, 2nd or plug? Always a problem when only one tap is used.

I would likely rough it out on the lathe and only use the tap for finishing the thread.

Certainly cutting the thread before machining will help...

Mark Elen 107/11/2019 19:30:25
117 forum posts
201 photos

Hi NDIY,

Taper Tap. I had a similar thought re roughing it out on the lathe, in fact I have bought a 55 degree 6mm internal hss tool. The problem is, the slide needs most of the machining doing, so that it can be held in place in the vice to get the hole in exactly the right place.

The other problem is that as the hole is only 11.1mm minor diameter, it needs a tiny internal threading tool. The part is 3/4 thick, so the tool is stuck out a long way in the tool holder. (Also, there is going to be a lot of very close up work to the Chuck. At least it is left hand, so all of the cutting will be going away and not towards the Chuck)

Cheers

Mark

Sorry, I have just clicked what you were saying re the tapping before machining. 
I will have a go at roughing it out on the lathe, once I get it machined down and the hole drilled. I can see a lot of hand winding of the tool back in coming.... I really need to get my hand winder that I have planned for the back of the lathe spindle made. 

Edited By Mark Elen 1 on 07/11/2019 19:55:22

Mark Elen 109/11/2019 13:14:41
117 forum posts
201 photos

I have got on and remade the vice slide block. I had to set up the vice riser again in the mill to drill for the screw hole:

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And here is the block I made that is a good tight fit in the slide, so that I could use an edge finder and the DRO to find centre:

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I then clamped up the vice jaw with a couple of small .8mm aluminium shims to hold the jaw and block in place while I drilled out to 11.1mm. You can just see them poking out of each side of the jaw:

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I then set it up in the 4 jaw and spent a long time getting the hole central on the lathe, followed by a lengthy set up of the change gears. The SC4 that I have would be OK for 16tpi right hand, but for left hand, the 120 gear hits the spacer in the gearbox when the 30 gear is swapped to reverse the lead screw. I ended up taking the spacer off, along with the woodruff key and holding the gear in place with a small washer that slid between the 120 and 127 gears. Not great, but usable.

After all that, the 6mm single point tool just sprang away from the hole and didn't touch it... Grr.

I ended up setting it up in the vice and tapping it by hand. It went better than last time, but not much.

Once that was done, it went back in the mill and I brought it down to finished size.

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All in and done. The vice is a little tight, though not overly, I'm hoping it will bed in and slacken off a little with use:

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Cheers

Mark

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