mini mill

[DaveH]

DA,

That's looks good

DaveH

[dallen]

heres a photo of the gib that goes in the slide that I have been working on, I didn't think to take a photo before I started working on the gib. The gib was only touching on the very ends when I started.

I still have a little bit of scrapping left to totally remove the big scratch that is/was down the middle of the gib.

One thing I will say is that any one attempting to do this is to get a piece of wood and cut a dovetail slot in it either in a mill or with a router. I would not of been able to of done the work on the gib that I did without the board that I fixed. I have to thank Kanal von MuellerNick while watching one of his videos on scrapping he showed the setup that he uses for gibs.

Enough rambling to the photos.

   

[DaveH]

DA,
That seems a favourite past time for gibs, they either touch at the ends or just in the middle

DaveH

[dallen]

(07-15-2012, 06:28 AM)DaveH Wrote: DA,
That seems a favourite past time for gibs, they either touch at the ends or just in the middle

DaveH

unless you make them flat this is the same gib just without most of the scratch, all that is left of it is within the blue circle.

The other piece that is in the photo is a prism that I cut out on my little 7 inch shaper yesterday and have been working on with the scraper and surface plate. Its starting to get pretty flat now but I still have a ways to go.

   

[Rickabilly]

Hello All,
When I did my trade (Fitter and Machinist) I did an advanced machine assembly course, eight or so weeks forty hours a week, specifically focused on machine assembly, flat surface scraping, bearing scraping, white metaling of bearings, alignment of shafts bearing blocks and roller tables, etc.

To answer the question raised earlier, when to scrape and when to machine, the answer is really simple when you think about it, Machime as much as possible get the part as near to perfect as you can with the machine tools at hand, and then scrape to perfection, It is just a matter of time usage and efficiency, machine tools are designed to work to very accurate tolerances and do it quickly, scraping is very slow so use it where required but save your time and fingers where you can by accurate setup and machining.

DA did almost exactly as I was trained to do, by machining the 0.003" off of the back of the slide block and then hand finishing, the only difference I was taught would have been to use a flycutter, trammed in as good as is possible and then take 0.001" cuts until the smallest witness mark of the original surface remains, then hand finish, as a flycutter would leave a more uniform finish there would be less hand finishing and by leaving a tiny witness you would guarantee that the smallest possible amount of material was removed.

But I have to say, my hat is off to you DA for getting stuck in and using your logic to come up with the right answers.

Probably the best lesson here is that machine tools are just big ole hunks of iron, and we shouldn't be too precious about the "black arts of the machine builder" if it needs squaring up just stick it on the mill and square it up, I have seen some folks go all "forum rage-y" about someone using a file to remove burrs on a vice, the simple facts are that no matter what, a piece that is 0.002" out of square needs fixing, so just fix it, if it has a burr knock it off either with a fine file, a scraper or a stone, but get rid of it.

Best Regards
Rick

[dallen]

thanks for the down to earth reply Rickabilly, to me its whatever works and is handy as I have no formal training as a machinist or fitter I just try to make the parts that I need to the best of my abilities, and learn something while doing it. Sharpening Scrapers looks about as simple as it can be, but I'll say this it isn't cause if the thing isn't sharpened just right it won't cut.


here is a photo of a couple scrapers that I throwed together out of some carbide pieces that I have and a piece of eighth by half flat bar just regular HR 1018. one I put a handle onto.

   

[Rickabilly]

If you are interested I can sketch up the supposedly "correct" way of sharpening a flat scraper, Most people just use what they are comfortable with, but there is a specific design and method that has been used for over a hundred years.
So if you want me to I will supply the sketch.
Best Regards
Rick

[Highpower]

Rick, please do that. I'm still using old files with the teeth ground off of them for scrapers, so anything I could do that might help their performance would be greatly appreciated.

[dallen]

I never turn down an offer for free information, I've seen pictures of the blades but no one seems to want to really let the secret out on how to grind a blade.

I watched one french video where they honed their tools straight across.

so yes please post the sketch.

[DaveH]

Rick,
Nice offer - Thanks

DaveH