Author Topic: External lapping/honing. Cylindrical piece. Different type of laps?  (Read 3171 times)

Offline PekkaNF

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I would have needed to resort lapping sometimes, sometimes I have managed without, sometimes I have done some of it, but I really don't have deeper understanding of it.

If the aim is produce geometrically true cylindrical surface, what is the difference between diffeerent types of laps?

1) There are "ring type" laps, often pretty narrow. This type:
http://www.gadgetbuilder.com/Lapping.html
http://www.americanlap.com/Holder.gif

2) Clamp type, often V or two rods and a stone, known often Delapena
http://modelenginenews.org/baby/images/baby_2-4.jpg
http://modelenginenews.org/eze/images3/eze3_cp_lap.jpg

Pretty good instruction (Someone posted this few years back, I think)
http://thebloughs.net/series/external-hone-2/

BUT

Which one produces most round cylinder?

Which one produces most accurate/straight diameter?

Or it just "depends"?

Pekka

Pekka

Offline NeoTech

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Re: External lapping/honing. Cylindrical piece. Different type of laps?
« Reply #1 on: October 22, 2015, 02:58:07 AM »
The good thing with the clamp type is that you arent really limited to only 2 stones if you are little bit fiddly and make em your self.
Of course the ringtype would produce a better and more uniform cylinder.. but, they cant really produce different sizes for obvious reasons.

So it depends on what precision you are looking for.
Machinery: Optimum D320x920, Optimum BF20L, Aciera F3. -- I have not failed. I've just found 10,000 ways that won't work. http://www.roughedge.se/blogg/

Offline Alan Haisley

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Re: External lapping/honing. Cylindrical piece. Different type of laps?
« Reply #2 on: October 22, 2015, 10:16:28 AM »
Lapping is not meant to perfect geometry. Consider that the amount of material removed is on the order of a ten thousandth or less of an inch, your geometry had better be pretty darn near perfect before lapping. Lapping is a surface treatment. What it does is produce a smoother surface, not a more accurate shape. With usual lapping compounds you will be polishing rather than shaping.