Cutting really thin grooves?

[cinqster]

Now here's one that I've not found an answer for yet, and I remember Gio wanted some advice on it a while back too.

I need to cut square shouldered grooves into alluminium bar about 2-3mm deep but less than 1mm wide - 1/8th 917 cylinders BTW!

Has anyone found a suitable cutting tool for such an operation?

My only idea so far has been to thin down a parting-off tool as the blade type tools are around 2mm thick.

[mikemechanic]

I've heard of people using a hacksaw blade as a cutting tool but never tried it myself, I would assume just shaping it like a parting off blade and mounting it in the tool post. It should be strong enough to cut through aluminum as long as it is secured to the tool post well.

Mike

[cinqster]

Cheers Mike. I've not heard of people doing it before but it had crossed my mind to give it a go! With luck the blade should fit the tool holder with a bit of packing...I'll let everyone know how I get on.

[gionc]

Well I'm not sure if I can to write that, since it's against any basic safety rule, but I'm used (LOL and I have yet 20 working fingers) to work with just a metal saw to do thin cuts: for sure it isn't your case: you'll do also some decent wall's finishing but the cut's surface is ever crap.

I done time ago a thin cutter: simply grinding the side of a tool with hard seamed insertion (we call it Vidia bit, carbide is the same?). I broken it after 2 second doing a sweet (not forcing it, so) cut: I guess I warm up too much the tool in the grind machine...

Now I'm trying to do myself a HSS thin tool but I found that problems:

1- isn't so easy to use properly the grinder: also just sharpen tools with a proper angle is a challange

2- HSS is dammn hard: the fact is useful to achieve a proper shape in some stages but if you need to cut out some material (ex. thin down a 4mm wide bit to 1 mm...) it would keep you hours (days)

3- someone said me to find the "green" kind as wheels for the grind machine: never found in hardstores here around. They said tha it's the correct grindstone for the HSS...

[MPWR]

A hacksaw blade will certainly cut aluminum- but they really aren't very rigid. I expect you can make a fixture to hold the hacksaw blade to cut as a lathe tool, but the blade would likely flex and your grooves would be inconsistent at best.

Here's another thought:

(From here)

Augie cut the cooling fins on each cylinder by holding the cylinder in a rotary table, and rotating them while cutting the grooves with a slitting saw. (I've actually held this little engine in my hand- it really is close to dime size.) Slitting saws can be had in 0.040" thickness, which seems would be about perfect. It would also be an easy way to do the rectangular cylinder heads- but you wouldn't need the rotary table.



On the other hand, if you're just doing the cylinders on a lathe and you need a 0.040" groove, 0.040" turns out to be exactly the thickness of commonly available cutoff blades (such as what comes with Sherline's parting tool holder). Again, they're not terribly rigid- but are much more so than hacksaw blades.



Cutoff blade

Not that I've put any thought into doing exactly this sort of thing....

[p9o1r1sche]

I cant think of any better idea than using a slitting saw. So, your working on a 1/8 917? I just got back from the Rennsport Reunion in Daytona Beach, where there were about 7 or 8 917s, including the 16 cylinder test car, a Hippie car, the 1971 LeMans winning car, and others. We had a model show there and someone brought in a full frame for a 917 in about 1/10 scale. I hope they finish it out.

[mike@af]

I'll see if I cant get a pic of one of my grooving tools. I machined a grooving tool from a blank that looks like a cutoff tool capable of cutting .005" grooves.

[MPWR]

Originally Posted by p9o1r1sche

I just got back from the Rennsport Reunion in Daytona Beach, where there were about 7 or 8 917s, including the 16 cylinder test car, a Hippie car, the 1971 LeMans winning car, and others.

You fiend. I hope you took lots of pics.

[lam90]

Here is the closest thing that I have used to do what you are asking. I have been using them for about six months and they truly are the best tool that I have found for parting or groving.



Heavy Duty Cut-Off Parting & Grooving Tools
Pre Ground M2 Tool Steel Bits
3/8" Shank Cutting Width 0.050" Cutting OD 1-1/4"

Here is the link to Ebay to get them.
http://cgi.ebay.com/3pc-3-8-Cut-Off-...QQcmdZViewItem

I don't know if he ships internationally but if you are interested and he doesn't let me know and I will be happy to help you get them.

Best regards,

Larry

Originally Posted by cinqster

Now here's one that I've not found an answer for yet, and I remember Gio wanted some advice on it a while back too.

I need to cut square shouldered grooves into alluminium bar about 2-3mm deep but less than 1mm wide - 1/8th 917 cylinders BTW!

Has anyone found a suitable cutting tool for such an operation?

My only idea so far has been to thin down a parting-off tool as the blade type tools are around 2mm thick.

[cinqster]

Thanks everyone for your response so far - what a cracking forum this is!

Gio, I'm a little worried you have a compliment of 20 working fingers, probably why you build so quickly!

MPWR, that's just the puppy I'm looking for! BTW, that exploded view appears to be for a 917 head - where on earth did you find that?!

Larry, thanks for your kind offer - I may well take you up on it and those cutters looks perfect too.

Po9o1r1sche, I think that they must have been your pictures I whipped off the GPMA board yesterday! Yep, I'm just in the planning stage of the 917 at the moment, as I've only drawn the 1/8th engine blueprints up so far from existing rough drawings and photographic reference. Interestingly, I found a message from someone on pbase that's 900 hours into a 1/8th 917 but I can't get hold of him, perhaps it was his?

There's a cracking gallery on pbase that has one of these beauties being built - it's invaluable for reference:

http://www.pbase.com/917carl/root

Mike, I'd love to see a photo if you can get one please.

[Murray Kish]

Always late to the party....

I only have one suggestion (from a total newb)....

What about putting an exacto blade into a toolpost somehow? They seem pretty rigid/stiff to me? Likely have to hold it so it cuts with the top of the blade (ie. the part opposite of the actual cutting edge), but I assume this would give a pretty thin groove? It should work on alum, no?? Or, perhaps a broken exacto blade shaped in such a way to work like a mini-cutoff tool?

Edit: perhaps there's even a way to stack several of them together (with spacers) so that you cut several grooves at once??

Anticipating laughter and mocking.... but a guys gotta learn somehow...

Murray

[mike@af]

Murray,
It works for awhile...until they brake. And when x-actos blades break...its like the fiery pits of hell exploding. Don't ask how I know.

Next time I'm home I'll try to get a pic. It looks like the parting tools posted above.

[gionc]

Originally Posted by GTmike400

Murray,
It works for awhile...until they brake. And when x-actos blades break...its like the fiery pits of hell exploding. Don't ask how I know.

Next time I'm home I'll try to get a pic. It looks like the parting tools posted above.

Yep Mike but did you machined down the cutting tool's bit or sand down in the grinder? May the mill's bit be able to machine down a HSS tool?

@ p9o1r1sche: I'm in love with vintage porsches from a while.... poooooost

[mike@af]

Originally Posted by gionc

Yep Mike but did you machined down the cutting tool's bit or sand down in the grinder? May the mill's bit be able to machine down a HSS tool?

I mounted a fiber reinforced cutoff wheel from a Dremel in the lathe chuck. Put the tool in the tool holder, and slowly ground it down to the with I wanted.

The tool can only cut grooves about .060" deep, which is deep enough for me. If I needed deeper I could make more passes but that may jeopardize the strength of the tool.

[its not unusual]

Aleks

http://www.its-not-unusual.de