# Something to help us "non" machinists



## davidyat (Sep 25, 2022)

*I purchased a set of plans for a Model Marine Engine. As I was starting the project, I noticed something that helped me immensely. Whenever there was a inside radius corner to be milled, the designer put in the plans where to begin and stop the "center" of the end mill so the edges would be right. I do put Dykem on projects and scribe the various edges so I don't do something stupid and ruin a part. I can see when I'm getting too close to an edge. I just thought this was a good idea for some of us who are not trained machinists. 
Grasshopper




*


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## Brian Rupnow (Sep 25, 2022)

I do that all the time on my engineering drawings.--Otherwise, the poor machinist has to set with a calculator and figure out where those points are. If you don't have these points clearly dimensioned on an engineering drawing, then it is just one more area where mistakes can be made.


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## Gordon (Sep 25, 2022)

I frequently make a CAD drawing on a separate detail sheet showing the readings required on my DRO so that I am not trying to calculate things while machining. I do this for things like cutting the cooling fins on a cylinder as well as showing the centers where holes or mill cutters should be in relation to a zero X & Y location. I usually just print out that one detail on a single sheet since I frequently end up with several of these details on the detail sheet. Frequently I will make a detail for separate operations like all of the locations which require a 1/4" end mill and a separate one for 3/8" etc.


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## davidyat (Sep 25, 2022)

*Thanks for suggestions I can use in the future.
Grasshopper*


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## SmithDoor (Sep 26, 2022)

davidyat said:


> *I purchased a set of plans for a Model Marine Engine. As I was starting the project, I noticed something that helped me immensely. Whenever there was a inside radius corner to be milled, the designer put in the plans where to begin and stop the "center" of the end mill so the edges would be right. I do put Dykem on projects and scribe the various edges so I don't do something stupid and ruin a part. I can see when I'm getting too close to an edge. I just thought this was a good idea for some of us who are not trained machinists.
> Grasshopper
> View attachment 140178
> *


If using a DRO or cnc you just set on corner to zero to do machine work. 

Dave


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## Ken I (Sep 26, 2022)

I sometimes do a 1:1 print from AutoCad onto a self adhesive sheet and stick that onto the job (carefully) - helps avoid making any really gross errors.

I also find my HP is more accurate than my marking out. Like the presentation base below :-




Regards, Ken


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## ChazzC (Sep 27, 2022)

Ken I said:


> I sometimes do a 1:1 print from AutoCad onto a self adhesive sheet and stick that onto the job (carefully) - helps avoid making any really gross errors.
> 
> I also find my HP is more accurate than my marking out. Like the presentation base below :-
> View attachment 140201
> ...


When mocking something up (like a mounting plate) that needs to conform with an existing machine I'll typically print 1:1, attach the print to a piece of cardstock using a glue stick (oversize junk mail postcards work great) and do a test fit.


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## costerjr (Oct 8, 2022)

Gordon said:


> I frequently make a CAD drawing on a separate detail sheet showing the readings required on my DRO so that I am not trying to calculate things while machining. I do this for things like cutting the cooling fins on a cylinder as well as showing the centers where holes or mill cutters should be in relation to a zero X & Y location. I usually just print out that one detail on a single sheet since I frequently end up with several of these details on the detail sheet. Frequently I will make a detail for separate operations like all of the locations which require a 1/4" end mill and a separate one for 3/8" etc.


As above. I make separate sheets with the DRO settings and end-mill, twistdrill, TPI and depth size. I designate the 0-0 point and everything possible is done in one layout from those coordinates.  With the piece in front of me, I recheck the coordinates and radius to make sure I am at the drawing measurement. When I'm done and everything is correct and verified, I go back to the CAD drawing and put a little circle with a big K in it some wheres on the bottom of the drawing.  Then if I want to reuse it in the future, I know it is good to go.  I make some work aids and fixtures for a couple of small Mom & Pop businesses.  They may call up and ask for a couple more of something I did two years ago. 

Looking at the supplied drawing in your case, there are so many dimensions my eyes would swim.  The possibility of an error is greatly increased. All the dimensions are needed and I have some drawings that look the same, including my own.  I would make a couple of copy's of what i was doing and white out almost all of the dimensions and layout lines not needed for that operation.  Then specify what drill size, notes  are needed for that operation only. If you put two different operations on a single sheet, I would use different colored highlighters on the points and notes.  Say green for 1/4" drill, red for 3/8" endmill, etc. I find it actually speeds up the machining this way.   Looking stupid with crayon drawings is better then being stupid with a missed machining operation. 

Just my two cents... Chewy


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