# Lathe Parting Tool - Hacksaw blade



## bananabearings (Mar 12, 2017)

I spotted an image of the tool on Pinterest. Noticed it was from this forum. Sadly the other photos in the thread were no longer available. The original poster The Emerald Isle - Dave, kindly provided a few more photos.

So ..... my first build thread.


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## bananabearings (Mar 12, 2017)

(photo) Kennedy saw


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## bananabearings (Mar 12, 2017)

(photo) Kennedy saw

(photo) Facing ends

(photo) Overview of Centec 2a.

(photo) first rebate cut

(photo) second rebate cut


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## bananabearings (Mar 14, 2017)

Milled the rebate, then cut the dovetail. Considered using a saw at 60 degrees, or three square file, but the dovetail cutter was in the drawer.

Recess is same depth as blade thickness - probably too shallow. I'll make it a little deeper this evening.


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## goldstar31 (Mar 14, 2017)

I seem to recall L.C.Mason- the traction engine guy, writing up the use of a worn hacksaw blade for parting off. His book, Using the Small Lathe seems to be still available and is worth a purchase.
Earlier, my father who was a blacksmith/farrier used 'machine' hacksaw blades to make all sorts of knives. Long before the WW2 because I used them for making 1/72nd scale models for these various events forWW2  National Savings drives. I recall that a 12" to the foot Spitfire was £5000! 

Seems like it was only yesterday!

Norm


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## deverett (Mar 14, 2017)

As you seem to be using All Hard blades instead of Bi-Metallic ones, you can use the blade either way up.  Although not absolutely necessary if using the blade upside down it is probably kinder to the tool to grind the teeth off first.

Dave
The Emerald Isle


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## django (Mar 14, 2017)

Isn't 12" to the foot Full Scale????? :wall::wall:


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## goldstar31 (Mar 14, 2017)

django said:


> Isn't 12" to the foot Full Scale????? :wall::wall:[/QU
> 
> In Spitfires- it was about that as they clipped the wings off some ours:hDe:


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## bananabearings (Mar 14, 2017)

I normally use bi-metallic blades, Dave. Pondered how far across the blade, the metal would be hard enough to cut.  Several worn blades in the drawer, from the Kennedy hacksaw. 

Bought the all 'hard' for the job. I'll give both a try.

David


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## bananabearings (Mar 14, 2017)

This morning, I compared what I had machined with the photo of Daves. I should have made a sketch, or kept the laptop open on the bench. 

I'll keep working. It appears to hold the blade securely. The two parts were clamped flat, for the photo. As seen in the photo, the tooth set takes it beyond the top. Wont be a problem with the worn blades. I shall, however, move the top (clamping the teeth) a little proud of the base - before drilling for the clamping screws.


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## bananabearings (Mar 14, 2017)

I have the L.H.Sparey book, The Amateur's Lathe. If the Mason book is available on Amazon, or a second hand bookseller, I may buy a copy. Thanks for mentioning it Goldstar.

David


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## goldstar31 (Mar 14, 2017)

Recalling what little remains of my memory, there are at least 3 variations of clamping.

The first is in Sparey's book, the Amateurs Lathe where the blade is clamped with suitably modified screws.   My copy dates back to Goldstar days!

The second is obviously L.C.Mason's and is a double clamp.

The third is the classic George Thomas one where the blade is clamped but tilted at 140 degrees and it all ends up on the rear of the saddle- upside down and where the blade cuts and narrows a ribbon of metal. My favourite incidentally.

Perhaps there is a 4th and that is Martin Cleeve's Heavy duty Parting tool described in Model Engineer and is supposed to be man enough to part off 4" diameter ms round- because the guy thought a hacksaw machine too slow.  Apart from the photos, I can only express amazement- rather than experience. 

Mind you what he didn't explain was that his ML7 had not only an additional front steady to the normal Glacier spindle bearings but the whole panjandrum had TWO motors- one half horse and the other a full ONE horse and the whole lot on fast and loose pulleys.

Well, yes??????

Norm


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## bananabearings (Mar 16, 2017)

M3 cap head screws. Completing a internal quality system audit of the maintenance dept at work yesterday morning.  The screws had been supplied with a set of bushes. screws not required for the job, so I was offered them.


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## pepi (Mar 18, 2017)

Seems to me a parting tool using a hack saw blade would be way too flexible, horizontal and vertical. 


Greg


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## Blogwitch (Mar 18, 2017)

Greg,

If the blade is held truly horizontal and it has a well shaped grooving cutter on the end, then they can make very good parting tools as long as you don't overload them.

I wouldn't try to cut through a 3" diameter stainless bar with one, but half inch mild steel, it should just about cope with.

I use this width of cutter for parting off small brass tubes or for cutting fins into the sides of cylinders, which if taken carefully without too much unsupported tip, seem to last forever.

John


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## pepi (Mar 19, 2017)

Hi John,

Cylinder head cooling fins did come to mind when I saw the tool and made perfect sense. 

3" diameter stainless bar..............That's a tuff one all on its own, think I would saw,  face that....LOL

Greg


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## Blogwitch (Mar 20, 2017)

Greg,
If you can get the tip ground up correctly (this is the most important part of using these thin grooving/parting tools) then they are almost indestructible in general use. I always ground them up parallel and found that side clearances were not required, so the hacksaw blade could be left as is except for grinding the teeth off  and putting on the cutting tip. These are 0.025" wide, parallel sided, on 1/4" blanks.






I did all these cylinders with just one cutter, and could have gone on for many many more, in fact it is still in my HSS tool collection if ever it is needed again.











John


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## Brian Rupnow (Mar 20, 2017)




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## Brian Rupnow (Mar 20, 2017)




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## bananabearings (Mar 21, 2017)

small ic engine? one of your own design John?


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## bananabearings (Mar 21, 2017)

Very useful Brian. Hopefully giving people the drawing, the 3D model assembly and the finished tool, will inspire them to have a go. Thanks. 
David


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## Blogwitch (Mar 21, 2017)

Banana,

No, a Liney Halo radial multi cylinder steam or air driven.

These were to make five different engines ranging from 1 to 5 cylinder, but still sitting at the back of a bench waiting for me to bring them back to life. Maybe or maybe not.

[ame]https://www.youtube.com/watch?v=g_5ENZmfCDk[/ame]


Here is Kvom's nice build

http://www.homemodelenginemachinist.com/showthread.php?t=5042


John


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