Cooling Fins

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BMyers
Posts: 81
Joined: Sat Dec 09, 2006 6:42 pm
Location: Iowa

Cooling Fins

Post by BMyers » Sat Jan 06, 2007 9:43 pm

What is the best tool to use on a lathe to cut cooling fins on cylinders ? I have tried using a parting tool but the blade wanders off to one side or the other.

Harold_V
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Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Post by Harold_V » Sat Jan 06, 2007 11:51 pm

A hand ground HSS grooving tool would do the job, and cost you almost nothing. In order to grind one successfully, you should have a firm understanding of why a tool cuts, and what features effect performance. That's not something you're likely to read in a book----it comes from trial and error. I can offer you some guidance if you'd like.

Understand, a properly ground tool won't be a compromise---it will do a great job and leave a decent finish---it's all in how you grind the tool and what lubricant you use while cutting. The sole exception to this is if you're machining mild steel, which can be very challenging.

Harold

BMyers
Posts: 81
Joined: Sat Dec 09, 2006 6:42 pm
Location: Iowa

Post by BMyers » Sun Jan 07, 2007 8:33 am

Harold,
what profile am I looking to grind to?
Last edited by BMyers on Sun Jan 07, 2007 12:00 pm, edited 1 time in total.

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Orrin
Posts: 307
Joined: Sat Jan 04, 2003 12:24 pm
Location: SE Washington State, near Moscow, Idaho

Post by Orrin » Sun Jan 07, 2007 10:46 am

I use a cutoff tool and have never had a problem. If your cutoff blade is wandering off to the southwest you might want to check a few things.

1) Have the cutting edge exactly at center height. You can check this with the old machinst's ruler trick. If your not familiar with the technique, you place one of those little 6" machinist's rulers between the cutting edge and the part being machined. Lightly advance the cross slide until the ruler is clamped between the two. If the edge is at the correct height, the ruler will be vertical. If not, it will be cocked off at an angle.

2) Make sure your cutoff tool is perfectly perpendicular to the lathe axis. One way to do this is to face off a piece in the lathe, then mount the cutoff tool and bring it alongside the faced surface. Place a piece of white paper on the ways below the tool to afford good visibility. Sight directly down onto the cutoff tool. If you see a wedge-shaped gap of light between it and the faced surface, you are not square. Adjust your cutoff tool until it is perfectly aligned.

3) Hone the edge of your cutoff tool razor sharp. When doing cooling fins I like to have the edge square with the tool. Make sure the corners of the cutting edge are not rounded off.

I like to use a slow RPM and powered cross-feed. I always use brushed-on kerosene as a lubricant for aluminum. This prevents a "built-up" false cutting edge that could make the tool go astray.

The results are very satisfactory as seen in the pictures on these Web pages:

http://users.moscow.com/oiseming/lc_ant_p/pic_Prj1.htm

http://users.moscow.com/oiseming/lc_ant_p/pic_Prj8.htm

http://users.moscow.com/oiseming/lc_ant_p/pic_Prj6.htm

Good luck!

Orrin
So many projects, so little time.

Harold_V
Posts: 18565
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Post by Harold_V » Sun Jan 07, 2007 3:57 pm

I have posted a picture, below, that shows a parting tool that is hand ground. It's the one on the right, with a different parting tool to its left, showing the side.

There's a real advantage to grinding your own tool. For one, you can grind the precise width you'd like to achieve, or, if you'd like to rough the fins and go back for a light finish cut, you can grind the tool slightly undersized, working to centers, then go back and take a skim cut off the sides of the fins. Unless your tool is terribly dull, it will take the cut with no problem, particularly if you're machining a decent grade of aluminum.

Right now I'm attempting to post on HSS grinding, but it's proving to be a difficult task for me. There are so many variables that it's difficult to set guidelines that might be helpful without knowing circumstances. Your case is no exception. If you can give me a little detail on what you're doing (depth and width of fins, and material being machined) I may be able to give you some specific guidelines. I've ground parting and grooving tools as long as I have memory of the shop and have never had difficulty with them. Nice thing is, they're not hard to grind if you're willing to change how you normally grind tools. I'll talk about that, too, if you're interested. I had planned to, anyway.

Harold
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tag
Posts: 8
Joined: Wed Nov 29, 2006 12:19 pm
Location: Ohio

Post by tag » Sun Jan 07, 2007 5:46 pm

Harold

Please DO the write up on tool grinding. It is something that all of us who are fairly new to this can use.

Thanks
Tag

Harold_V
Posts: 18565
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Post by Harold_V » Sun Jan 07, 2007 9:42 pm

Tag,

It's in process as we speak. I've put in considerable time composing something I hope will be of assistance, but it's far from finished. I will also grind a tool and post a picture that is representative of one of the most useful and functional of all hand ground tools, a boring bar. Anyone that can duplicate the design with success will come to understand the value of the method I use. A bar such as this is truly superior to almost any other bar available.

Please be patient- I'm spread thin---and still struggling for words. :cry:

Harold

Abby
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Joined: Mon Jan 01, 2007 7:15 pm
Location: COVENTRY UK

Post by Abby » Tue Jan 09, 2007 5:24 am

Problems with deep parting or grooving can often be overcome by using a back post , the tool being upside down of course !

jones
Posts: 18
Joined: Fri Oct 28, 2005 2:19 pm
Location: Sydney. Australia

Post by jones » Tue Feb 20, 2007 6:03 am

Hey,

I just found this post and remembered a website that has information on cutting model engine cooling fins.
http://modelenginenews.org/techniques/fins.html

Enjoy
Andrew

NickH
Posts: 15
Joined: Tue Sep 19, 2006 5:27 am

Post by NickH » Wed Feb 21, 2007 7:06 am

You can use a cross slide mounted milling attachment

http://i135.photobucket.com/albums/q158 ... C00712.jpg

in conjunction with carbide slot drills & endmills the possibilities are, as they say, endless,
Nick

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