Lathe Parting Tool - Hacksaw blade

[bananabearings]

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.

 

[bananabearings]

(photo) Kennedy saw

 

[bananabearings]

(photo) Kennedy saw

(photo) Facing ends

(photo) Overview of Centec 2a.

(photo) first rebate cut

(photo) second rebate cut

 

[bananabearings]

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.

 

[goldstar31]

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

 

[deverett]

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

 

[django]

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

 

[goldstar31]

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:

 

[bananabearings]

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

 

[bananabearings]

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.

 

[bananabearings]

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

 

[goldstar31]

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

 

[bananabearings]

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.

 

[pepi]

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


Greg

 

[Blogwitch]

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

 

[pepi]

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

 

[Blogwitch]

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

 

[Brian Rupnow]

 

[Brian Rupnow]

 

[bananabearings]

small ic engine? one of your own design John?