Capabilities: Is a 1 hp PM mill enough for 18-8 stainless steel? Or 2 hp?

You can also do the reverse - mount a smaller fixture plate in a vise to be able to clamp unusually shaped parts. This particular mini-fixture plate is from Saunders:

31951958988_3f86de6fd6_k.jpg
31951958948_a882ee7405_k.jpg
 
@Aukai , @ErichKeane

I made a poor man's fixture plate, but I wanted it to be a consumable backer board for small parts and did not need the precision of your nice fixture plate. So I made it from a piece of scrap 1" thick Nylon that I had laying around. One can tap the holes, but don't really need to do so as machines screws can be driven right into the drilled holes. CNC drilled all of the holes as well as the counter sunk holes for its clamping to the table. When it gets cut up, if it does, it can easily be resurfaced. At the attached posting are some pictures.
B2 said:
Attached are a some pictures of the backer board being made. I will post some photos of the first project I used the backer board for in the next posting.
Click to expand...
Dave L.
 
B2 said:
@Aukai , @ErichKeane

I made a poor man's fixture plate, but I wanted it to be a consumable backer board for small parts and did not need the precision of your nice fixture plate. So I made it from a piece of scrap 1" thick Nylon that I had laying around. One can tap the holes, but don't really need to do so as machines screws can be driven right into the drilled holes. CNC drilled all of the holes as well as the counter sunk holes for its clamping to the table. When it gets cut up, if it does, it can easily be resurfaced. At the attached posting are some pictures.

Dave L.
Click to expand...
Thats a neat idea! I found a cheap-ish plate of 9x12x1 or so aluminum and used that. I actually 'oopsie' marked it not long ago, so I probably have another facing op coming on it soon.
 
davidpbest said:
You can also do the reverse - mount a smaller fixture plate in a vise to be able to clamp unusually shaped parts. This particular mini-fixture plate is from Saunders:

View attachment 433025 View attachment 433026
Click to expand...
Cool. Yea, I can see the benefit and the benefit is how you use it with a small or large fixture plate. Whether you have 1/4, 3/8, 1/2" holes and pin locating holes or how intricate your hole pattern is I guess it really doesn't matter that much.

I'll head @ErichKeane advice and buy or farm it out to someone with a CNC if I try this out. Seems most are in aluminum, or softer material, any reason why not to have one made out of thick steel?
 
skcncx said:
Cool. Yea, I can see the benefit and the benefit is how you use it with a small or large fixture plate. Whether you have 1/4, 3/8, 1/2" holes and pin locating holes or how intricate your hole pattern is I guess it really doesn't matter that much.

I'll head @ErichKeane advice and buy or farm it out to someone with a CNC if I try this out. Seems most are in aluminum, or softer material, any reason why not to have one made out of thick steel?
Click to expand...
Aluminum is nice since you can re-finish it easily enough by running the mill over it. Otherwise I suspect is the weight of the thing. Smaller mills already have a hard time moving around a 50+lb vise, adding a huge steel plate would probably make the table tough to move.

Also, aluminum is cheaper by volume typically for plate :)
 
skcncx said:
Cool. Yea, I can see the benefit and the benefit is how you use it with a small or large fixture plate. Whether you have 1/4, 3/8, 1/2" holes and pin locating holes or how intricate your hole pattern is I guess it really doesn't matter that much.

I'll head @ErichKeane advice and buy or farm it out to someone with a CNC if I try this out. Seems most are in aluminum, or softer material, any reason why not to have one made out of thick steel?
Click to expand...
Have a look at this fixture plate from Saunders. The Tormach 1100 has a table about the size of the mills we've been discussing here. That plate in 6061 aluminum is $800 and for all the work involved, that's a bargain IMO. The same plate in 7075 is $1200, and in 4041 is $1600. I would not want a plate this size in 4041 if I were thinking of moving it on/off the table frequently because of weight.
 
One of the advantages of the Nylon was that I drilled all of those small through holes (sized for # 6 or #8 screws) with a single drill bit and of course without any cooling. It was dulling by the time I was done, but it would never have lasted in Al, and certainly not if the plate had been of steel. I stopped drilling holes as I figured it would be easy to add them as needed and they really did not need to be through holes. If you did not notice the picture of the bolts used to clamp to the table you might do so. I turned the back sides of the heads of these counter sunk head bolts down so that they had minimal thickness..... then by using flat bottomed counter sunk holes the final thickness is about 0.1" of Nylon. So the clamping bolts are deep or about .85-.9" below the surface of the 1" thick Nylon. Lots of depth for resurfacing before I reach those bolts! By the way, some of the holes are for alignment. I insert drill rod through these plate holes and then let them fined the table.... and then these locate the plate to the table features. Hence the nylon and the holes are always parallel to the table travel. The nylon is soft, but the alignment is probably good to a few thousands over the 22" length of the board.

I am not for sure what the original purpose of this nylon was. I found it at local surplus store years ago and could not pass up the unused 4'x4'x1" sheet. I keep cutting pieces of it off and using it for small projects, as you can see, including the RPM hall sensor magnet(s) mount for the spindle on my lathe.

However, after seeing the recent postings and great photos here, I may have to have one of those real fixture plates!!! I especially like the look of the solid "gold" clamps against the bright Al in David's posting of the Saunders plate!

Dave L.
 
I've had a chunk of cast aluminum around for quite a while that I've intended to make into a fixture plate. It has lugs on the back that I'll make it easy to vice mount. I just want it for smallish castings that I make. They are always difficult to hold. Yes, I expect it to be tedious to tap all the holes, DRO & a spiral tap to power tap. Some day?
 
I snapped a pic of mine, 7*11*1 with 77 tapped holes :)

I'm into it for just the metal (roughly $40 IIRC), but like 15 hours of drilling/tapping.
 

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