Author Topic: fly cutter (Read 91400 times)

wongster · « **Reply #25 on:** August 17, 2010, 01:20:32 PM »

David,

Appreciate that.

Regards,
Wong

wongster · « **Reply #26 on:** August 21, 2010, 01:30:22 PM »

Bill, hope you don't mind if I use your thread to ask my question on the tool I grind.

Spent quite some time in my shop today to attempt to grind the tool with the big radius on 1/4" square HSS for flycutting. This is what I get:

View from top.

From the end.

From the radius.

The result is rather crude and doesn't seem to work well as the part of the radius that came in contact with the work piece was very near the shank of the tool. I'll study the photos again to see what went wrong with my grinding. Don't know if its because of the angle of the flycutter body holding the tool being too shallow.

One thing I did learn today which I'm rather happy about; I got a good feel for free hand grinding. Took the opportunity to "repair" those damaged HSS bit I kept and did some test cut. Not too bad.

Anyone have pics of this type of tool touching the stock? Want to see which part of the radius should be doing the cutting.

Regards,
Wong

fatal-exception · « **Reply #27 on:** August 23, 2010, 06:51:06 PM »

Front the front of the tool, try to make the radius as smooth as possible for the best surface finish. You will want to do the final honing with a diamond or some other stone. Only the leading edge of the tool cuts, so it doesn't matter about the part of the edge closest to the shank, unless your tram is that far out.... What you have ground there looks fine to me. If your not happy with it, keep trying till you get it right. Remember, it doesn't matter what it looks like, it matters how it cuts. As long as you have adequate relief on the front and bottom, it should cut fine.

(sorry iPhone in dark shop...)

wongster · « **Reply #28 on:** August 23, 2010, 06:56:28 PM »

Thanks for the tip.

Wow, yours seem to be a rather deep cut. I'm only doing max of 0.25mm per pass, as recommended by Sherline. But I'm usually on around 0.15mm to 0.2mm.

Regards,
Wong

Bernd · « **Reply #29 on:** August 23, 2010, 07:22:10 PM »

Quote from: wongster on August 23, 2010, 06:56:28 PM

Wow, yours seem to be a rather deep cut. I'm only doing max of 0.25mm per pass, as recommended by Sherline. But I'm usually on around 0.15mm to 0.2mm.

That all depends on the size of your machine and rigidity of the spindle. If you have a Sherline then go by their recomendation until you get used to how deep a cut it will acutally do.

Bernd

wongster · « **Reply #30 on:** August 23, 2010, 08:07:05 PM »

Thanks Bernd. I'm quite comfortable with up to the recommended 0.25mm. For the sherline flycutter with a left hand tool mounted, the recommended spindle speed is 1/2 of the usual for any given material. Found that the surface finish wasn't really nice. It gave a nicer finish with full spindle speed of 2800rpm on aluminium.

So far this flycutter has been giving me better result as compared to the one with insert (also by sherline). The one with insert gave circular scratch marks on the surface.

I'll try grinding the rounded tool again to see if I can get that right.

Next task for the QTCP holder is to mill the slot before doing the dovetail. Have a couple of questions on that. I'll put them in the thread I started on this little project.

Regards,
Wong

sportandmiah · « **Reply #31 on:** August 23, 2010, 11:08:05 PM »

Bogstandard's pictures make no sense. The "Top" doesn't appear on the top, but on the side. And the cutting edge is on the top also? What does "top" mean?

wongster · « **Reply #32 on:** August 23, 2010, 11:40:22 PM »

This is my take on your question:
We're using left hand tool for this. When placed in the slot of the fly cutter, the top of the tool faces the side. So the top is now the side in this orientation.

Regards,
Wong

No1_sonuk · « **Reply #33 on:** August 24, 2010, 09:24:40 AM »

Quote from: wongster on August 23, 2010, 06:56:28 PM

Wow, yours seem to be a rather deep cut. I'm only doing max of 0.25mm per pass, as recommended by Sherline. But I'm usually on around 0.15mm to 0.2mm.

I might be wrong, but it looks like a block of Delrin (plastic). That could explain the deep cuts.

Quote from: wongster on August 23, 2010, 11:40:22 PM

This is my take on your question:
We're using left hand tool for this. When placed in the slot of the fly cutter, the top of the tool faces to the side. So the top is now the side in this orientation.

I believe that is the case.
Think of it as a lathe tool. If you used a lathe tool as a fly cutter, you'd need to turn it on its side.

fatal-exception · « **Reply #34 on:** August 24, 2010, 04:55:18 PM »

I'm not using that cutter on a Sherline, and yes it's a block of HDPE plastic. 1/8" in that stuff is a light cut.

I agree that the pictures are confusing. Even if your turning a lathe tool on it's side, it should be labeled as it would be held in the tool holder.

Just my 2 cents.

Paul

wongster · « **Reply #35 on:** August 24, 2010, 06:57:57 PM »

Paul: I meant to say that I can only do max of 0.25mm per pass. It always wow me when I see videos or photos of machines being able to do such a deep one (non Sherline), especially those turning videos. Didn't know its not metal

All: can I grind those brazed on carbid tool? I've 2 pieces of left hand that were chipped sometime back. Couldn't bear to throw them away.

Regards,
Wong

No1_sonuk · « **Reply #36 on:** August 24, 2010, 08:04:53 PM »

Yes, you can grind carbide, BUT you need a special wheel for it.

If you try to grind carbide with an ordinary wheel that's meant for HSS, you'll just grind away the wheel and not the tool.

wongster · « **Reply #37 on:** August 24, 2010, 08:23:12 PM »

You have the name of the wheel?

cidrontmg · « **Reply #38 on:** August 24, 2010, 09:53:42 PM »

Ask for a silicone carbide grinding wheel, they´re usually green. See this
http://www.rdgtools.co.uk/acatalog/Grinding_Wheels__silicone_.html
I grind mine with a diamond cup wheel, bought it from RDG Tools several years ago, and it´s still like new.
http://www.rdgtools.co.uk/acatalog/100mm_Diameter_Diamond_Grinding_Wheels.html
Mine is the 2nd from top. Diamonds may be the girls´best friend, but they are nice in the shop as well

P.S. I use the diamond wheel ONLY for sharpening carbide tools. They will cut anything, of course, but HSS tends to clog the wheel, so it will appear blunt, which it really isn´t, but can be difficult to clean.

fatal-exception · « **Reply #39 on:** August 24, 2010, 10:37:06 PM »

Here's the only 2 pictures that are needed in my opinion:

The black line near the tip is some built up HDPE plastic that I didn't notice when I took the picture.

This tool is held in the cheapest, worst finished piece of Chinese cra..er..steel that I've ever had in my shop...but it works.

It made all these blocks the same size within .002" in either direction. Not bad for a hand ground tool and horrible tool holder!

again

wongster · « **Reply #40 on:** August 25, 2010, 01:43:03 AM »

Hi cidrontmg,

Any idea is those cup type got to use with different type of grinder?

Regards,
Wong

Stilldrillin · « **Reply #41 on:** August 25, 2010, 02:20:05 AM »

Wong,

I use a 50mm dremel type, diamond disc........

Works well, for me!

David D

cidrontmg · « **Reply #42 on:** August 25, 2010, 09:11:28 AM »

Quote from: wongster on August 25, 2010, 01:43:03 AM

Hi cidrontmg,

Any idea is those cup type got to use with different type of grinder?

Regards,
Wong

Hi Wong, I use my cup wheel in a 20€ Chinese grinder, for the time being at least. I´ve been thinking of making a more elaborate tool grinder, but not yet done much about it. Collected some parts. Another project for the future...
I obviously needed to take off the wheel protection. That´s not any danger, the diamond cup is aluminium, so it won´t shatter (don´t take the protection off with any "stone" wheel, though!). Also, I needed to turn a spacer and a washer for the cup wheel, it has a bigger hole than the grinder axle. Just some aluminium bar stock, nothing fancy. But reasonably accurate, so the cup wheel runs as true as you can get it.
There´s also a small table to hold the tool piece. The wheel cuts with its "outward" side, so the table is towards that end.
Tried uploading pictures to Photobucket, got this
"Photobucket Site Maintenance
Images and videos may continue to serve during this short maintenance."
So some pics and notes here.
The grinder tables rust in an instant when they get wet from the water-cooled tool bit... Just surface rust, but they don´t look nice. The diamond wheel table is rather flimsy, but has served its purpose. I should have built something looking more like the other end table, but contemplating about a far more elaborate tool grinder has put that table on hold... Function comes before good looks, and I like ball handles...

wongster · « **Reply #43 on:** August 25, 2010, 10:38:45 AM »

Quote from: fatal-exception on August 24, 2010, 10:37:06 PM

The black line near the tip is some built up HDPE plastic that I didn't notice when I took the picture.

Can I say that the black line is the edge that was doing the cutting? Mine was further up to the left (the straight part) of the cutter in your pic. Could be the angle of my holder.

wongster · « **Reply #44 on:** August 25, 2010, 10:42:11 AM »

Quote from: Stilldrillin on August 25, 2010, 02:20:05 AM

Wong,

I use a 50mm dremel type, diamond disc........

Hi David,

The block behind - wood?

Regards,
Wong

No1_sonuk · « **Reply #45 on:** August 25, 2010, 11:15:36 AM »

Quote from: wongster on August 25, 2010, 10:38:45 AM

Can I say that the black line is the edge that was doing the cutting? Mine was further up to the left (the straight part) of the cutter in your pic. Could be the angle of my holder.

Yup. The curved part is what's supposed to be cutting.

Stilldrillin · « **Reply #46 on:** August 25, 2010, 04:19:52 PM »

Quote from: wongster on August 25, 2010, 10:42:11 AM

Quote from: Stilldrillin on August 25, 2010, 02:20:05 AM
Wong,

I use a 50mm dremel type, diamond disc........

Hi David,

The block behind - wood?

Regards,
Wong

Just a disc of 12mm plywood.......

David D

No1_sonuk · « **Reply #47 on:** September 11, 2010, 05:06:09 PM »

Quote from: No1_sonuk on August 24, 2010, 09:24:40 AM

Quote from: wongster on August 23, 2010, 11:40:22 PM
This is my take on your question:
We're using left hand tool for this. When placed in the slot of the fly cutter, the top of the tool faces to the side. So the top is now the side in this orientation.
I believe that is the case.
Think of it as a lathe tool. If you used a lathe tool as a fly cutter, you'd need to turn it on its side.

I took this statement of mine, and a bit of

struck me. See the attached images.

That's a 5mm dia. profiling tool on an 8mm holder.

j45on · « **Reply #48 on:** September 11, 2010, 05:28:07 PM »

great idea is that the finish under the tool ?

No1_sonuk · « **Reply #49 on:** September 11, 2010, 05:38:37 PM »

Yup.
It looks rough, but it feels smooth - I'm assuming my lack of flycutting experience contributed to the look of it.

BTW, that block is aluminium.

News:

Author Topic: fly cutter (Read 91400 times)