So the Kwik Way FN boring bar has only two spindle RPMs: 263 and 490. That is not a lot of adjustment for a machine that goes from 2.65" to 5.33" bores. Does anyone know what the correct cutting speed (fpm) is supposed to be for a cast iron block when using a carbide Kwik Way factory roughing bit? For what it is worth, I am currently doing 4" bores so 263 RPMs is 275 fpm and 490 RPMs is 513 fpm.
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Kwik Way FN Boring Bar Speeds and Feeds
- Thread starter graham34
- Start date
- Replies 6
- Views 4,500
Limy Sami
Diamond
- Joined
- Jan 7, 2007
- Location
- Norfolk, UK
Thanks for the link to the manual. I have spent hours on the internet trying to find an answer and I have looked through many manuals; however, all of the Kwik Way manuals say how to set the machine but fail to say what to set it to so I was hoping I could find someone here with more experience with the FN then me.
slowmotion
Cast Iron
- Joined
- Mar 31, 2013
- Location
- Danville Virginia
I used an FN for about 20 years before upgrading my boring equipment. And I still have it. I never bored on the fast feed/speed unless I was sleeving and needed lots of material gone. But you generate lots of heat so you have to let the block cool down before a final cut on slow/slow. If you bore on anything other than slow, you'll get almost .001" taper in the bottom from the heat generated at the tip. The narrower the cutter face angle, the better the finish but it requires frequent sharpening.
There are aftermarket holders available that use a triangle shaped insert. It's what I used for a long time. Finish is not as good as the oe carbides but if honing after it matters not. HOWEVER, you need to re-calibrate your mic as this tooling will read differently from the original, as it puts the cutter tip off center as compared to the oe cutter.
There are aftermarket holders available that use a triangle shaped insert. It's what I used for a long time. Finish is not as good as the oe carbides but if honing after it matters not. HOWEVER, you need to re-calibrate your mic as this tooling will read differently from the original, as it puts the cutter tip off center as compared to the oe cutter.
I used an FN for about 20 years before upgrading my boring equipment. And I still have it. I never bored on the fast feed/speed unless I was sleeving and needed lots of material gone. But you generate lots of heat so you have to let the block cool down before a final cut on slow/slow. If you bore on anything other than slow, you'll get almost .001" taper in the bottom from the heat generated at the tip. The narrower the cutter face angle, the better the finish but it requires frequent sharpening.
There are aftermarket holders available that use a triangle shaped insert. It's what I used for a long time. Finish is not as good as the oe carbides but if honing after it matters not. HOWEVER, you need to re-calibrate your mic as this tooling will read differently from the original, as it puts the cutter tip off center as compared to the oe cutter.
Thanks slowmotion! That is what I was thinking but I wanted someone with more experience to agree. What do you think the "comfortable" (don't want to press it) limits are on depth of cut? Is it necessary to make a pass with the oe finishing bit after the oe roughing bit when I am going to hone it anyway? I leave 0.003" for honing.
slowmotion
Cast Iron
- Joined
- Mar 31, 2013
- Location
- Danville Virginia
I never took more than .025" depth of cut (.050" on dia). Are you doing just normal oversize boring, like .030" and .040"? You can easily bore to within .003" on up to .040". At .060" I'd take 2 cuts.
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