Camel Back Casting Setup For Dovetail Machining

[sbx]

Hi all,

I've been struggling with the setup for holding my 18" camel back straight edge casting on my PM25MV.

I have only two small V Blocks to work with, and I think its time to get a larger set. But, how big, or are there some other ideas out there.

18" is right on the edge of my mills X capacity. I was able to pull off the flat bottom.

So, my thought right now is to get some larger import cast iron V Blocks.. Clamp those to the table, then strap clamp the casting down.

Any thoughts or alternative ideas before I hit up Enco's latest sale? Thinking of picking up the 5" V block pair.

Thanks in advance for ideas

 

[Bob Korves]

Are you milling the camelback before scraping it in? Did the work on the bottom leave you still with the angled edge to rough mill for doing dovetails? How rough is the angle portion of the casting?

 

[sbx]

Bob - It was a raw/rough casting, that I am machining in preparation to scrape in. I milled the bottom flat surface with a facemill, and did the 90 degree side already. This is the dovetail section. So, I am trying to fixture it, and having difficulty. I know it is because of my small v Blocks. So, just throwing ideas out there to see what others have done.

I've already ruled out welding up a fixture, as I would have no way to get the angles tight enough.

I think larger clampable (to the table) V Blocks will do it. But figured I'd post in case someone had a some other ideas. Even import cast iron V blocks would be close enough.. and I could scrape those in for fun/practice too.

 

[Bob Korves]

What angle do you plan to machine it to? Just hoping you realize that you do not use a 55 degree angle camelback to spot 55 degree dovetails...

 

[4GSR]

Why not? I've done this many times over the years with 60 degree straight edges I have. Just because Connley and Richard say not to do it, so doesn't make it right.
This has come up several times in the past here. I fully understand why you don't do it. And I respect everyone's view point on it too. Ken

 

[sbx]

I was thinking of cutting it just at or just under 45 degrees. Shimming the base up a little off the V-Blocks. All my dovetails that I plan to scrape in are currently 60 degree. A south bend 9A cross slide, and maybe touch up my PM25MV. Or Just machining it at 45, and scraping down a degree or so.

 

[Uglydog]

Why not? I've done this many times over the years with 60 degree straight edges I have. Just because Connley and Richard say not to do it, so doesn't make it right. This has come up several times in the past here. I fully understand why you don't do it. And I respect everyone's view point on it too. Ken

Ken, these word are filled with wisdom. Historians are the only real judge of best practice. My bias is clearly medicine, and the many changes that best practice sees everyday.
What I hear you saying is listen to the Subject Matter Experts and then do the right thing (which might be different from "best practice").
Results might be far better or much worse. Regardless that's how we evolve. Without risk there is no progress....

sbx, the great thing about HM is that while there is a lot of expertise. There are very few who suggest that their way is the only way. Korves & 4gsr once again speak wisdom.

Incidentally, I've found that the initial scraping of a milled surface is relatively more difficult that scraping a shaped or planed surface.

Daryl
MN

 

[4GSR]

......snip........

Incidentally, I've found that the initial scraping of a milled surface is relatively more difficult that scraping a shaped or planed surface.

Daryl
MN

You're learning and gaining experience Daryl!!! That's what this is all about.

There is definitely a difference between scraping a "planed" surface and one that has been "milled", especially if it's roughly milled surface. One of my early learning experiences in scraping.

Ken

 

[sbx]

Was that an offer for a Shaper or a planer? Haha. Just working with what I've got. The face mill leaves a pretty decent finish. Just maybe a little more work.

I ordered some larger V Blocks off enco, and will try again.

 

[chevydyl]

I machined my CB at 45 deg, or a hair under I spose, if you have a tilt table, use that, it's what I did, clamped it to the tslots, leaving the edge overhanging, worked great. Remember this is not a gage, it doesn't have to be perfect, your only using one surface at a time....

Bob, I think you missed the point of his question, he wanted to know how to setup or hold it, not ask him a bunch of questions on how to make his dovetail camelback....