Educate me on "brass barrel laps" please

[Brian Rupnow]

I am thinking of buying a "brass barrel lap" from Travers Tool to use for lapping the 1" bore on the cast iron cylinder of the engine I am building. I have never used one, and I don't know anyone who has. I have always made my own "one time use" laps by turning a piece of round aluminum to .002" to .003" less than the diameter of the cylinder bore, and using successive grades of carborundum paste to lap the bore. I would like to hear from anybody who has used these adjustable brass barrel laps. Does lapping wear them out?---are they a valuable item to purchase in terms of usage?---I am ready to move up a notch from my home made laps, but I would like to hear a bit about these brass barrel laps from knowledgeable users.----Brian
http://traverscanada.com/skulist.asp?RequestData=CA_Search&navPath=All+Products%2F%2F%2F%2FUserSearch1%3Dlap&q=block+id+112470+and+class+level3+id+29980&minPrice=$3.23

[GailinNM]

Brian,
I used to make my own laps but switched to Acro laps over 15 years ago.  Acro is the brand you are looking at. I have never used any as big as what you are looking at.  The ones I have used range from 0.140 to 0.625 inch diameter but they all work the same.
In operation there is very little wear on the lap.  You should get several barrels, on for each grit that you use.  The abrasive is embedded in the lap and no amount of cleaning will remove it.  When you remove a barrel tag it so you know what grade abrasive it is charged with.

I use diamond compounds by preference but carborundum will work the same way. It only takes a little bit of abrasive compound.  You don't use any heavy pressure.  Just let the lap do the work.  You can feel 0.0001 taper in the hole by the pressure on the lap. Use lots of light oil and never let it get dry when cutting or it will seize. 

Gail in NM

[sshire]

Brian
I've used Acrolaps with various grades of Timesaver.
Priced reasonably. Made in USA.
As wear goes, the adjustments take care of any.
http://www.acrolaps.com/

The nice thing about Timesaver is that it self- destructs and stops cutting.

[derekwarner]

.........light diametrical pressure between the hone/lap stones against the bore and a high flow rate    of flushing fluid will always assist   ...

[this is irrespective of the material being honed......steel, iron, bronze, brass are all OK...........Al or Cu are not really suitable materials to hone  ]

Let the stones  do the work.....not the pressure   ........ Derek

[Jasonb]

Derek, they don't have stones, excess flushing will wash away the charge of lapping compound and they will be doing nothing.

J

[Allen Smithee]

Different processes, different requirements Hones hone, laps lap. Each have their place. After all, you wouldn't expect a good lap dancer to be a good home-maker would you? It's much the same sort of thing really...

 

AS

[Allen Smithee]

Are barrel laps like this available in the UK?

AS

[Roger B]

I have not found a source in Europe yet. There is a Swiss/French company offering incredibly precise cylindrical laps at incredibly high prices 

As I said in another thread I ordered directly from Acrolaps in the US. 15 and 25mm sizes with two spare laps each cost 28 USD p&p.

[Bearcar1]

Different processes, different requirements Hones hone, laps lap. Each have their place. After all, you wouldn't expect a good lap dancer to be a good home-maker would you? It's much the same sort of thing really...

 

AS

Why yes. Yes I would expect that…It would all depend on how well she can dance. But then again, I am most easily distracted….

[tvoght]

I used an 11/16 Acro-lap on the cast iron cylinder of my recent Stirling engine build, and an 1/8" inch in the bronze displacer rod gland. I liked them.

No matter whether the lap is off-the-shelf or shop-made, one will profit greatly by reading (and reading again) the thread that Ramon started on the lapping process:

http://www.modelenginemaker.com/index.php?topic=1908.0

--Tim

[Brian Rupnow]

Thanks for all the answers guys. I forgot to click on the "notify" button and consequently didn't know anybody had answered me. After all of the answers I have received on this and other websites I decided to just go ahead and use a piece of round aluminum and carborundum paste like I have always done.---Brian