View Full Version : CNC machined Pacemaker lens boards... Worth the price?

3-Jul-2012, 15:46
Sorry in advance for asking such a specific question here (I also asked on Graflex.org), but you good people have been very tolerant of similar questions in the past, so I will try one more time.

I am waiting on a price quote from SK Grimes, but I am about to mount a 6.5" Petzval (thanks, Eddie) to a Pacemaker Crown and I am wondering whether the CNC machined boards (http://www.skgrimes.com/whats-new/2007-2/new-cnc-machined-pacemaker-lensboards) made by SK Grimes are worth the extra money they're bound to cost. It's not a super-heavy lens (I will weigh it when I get home), but it's heavy enough to give me pause in mounting it to a standard, stamped aluminum board. These are the Pacemaker boards with the lip around the edges. For all my other lenses, I use the stamped aluminum boards, but I am just wondering if anybody out there has any experience with these machined (out of a solid block of aluminum) boards or can attest to the strength they provide over the standard ones.

Otherwise, I guess I'll be using rubber bands just to be sure...


edit: On second thought, any advice about mounting heavier/longer lenses to a Pacemaker Crown or Speed Graphic would really be appreciated. So if you can give me any idea at all what sort of weight you can hang off the front standard of a Crown, feel free to chime in.

3-Jul-2012, 16:05
Now I'm just thinking out loud, but given that the outside diameter of the mounting flange is fairly close to the maximum size that one of these boards can accommodate, should my concern be less about the strength of the board and more about the strength of the locks that hold the lens board to the front standard?

Drew Wiley
3-Jul-2012, 16:29
CNC is actually the cheap way to do things nowadays. Compare that to die-casting like a
genuine Linhof or Sinar board, where the individuals dies could have cost tens of thousands apiece. Casting is a totally different ballgame and associated with import "pot
metal" crap. That being said, Grimes does nice work.

3-Jul-2012, 16:45
I've used heavy Aero-Ektar lenses on the stock Pacemaker boards with no problem. I doubt you'll hang anything heavier than that off of a Speed.

Frank Petronio
3-Jul-2012, 17:30
You'd be better making a wooden or foam support block to position under the lens between it and the focusing bed.

3-Jul-2012, 18:47
Thanks Frank, Corran, and Drew. I will buy the standard lens board and cut a foam support block. Assuming the flange focal length is between 175 and 200mm, there should be enough room on the rails for a sufficient support block. I feel a little stupid for not having thought about that myself, but this is my first barrel lens, so I'll cut myself a little slack...

Anybody else with tales of massive lenses attached are still welcome!

3-Jul-2012, 23:14
Generally speaking you'll have less problems with larger-diameter lenses.
This is because there's less metal between the hole and the edge of the board.
The smaller the amount of metal, the less deflection for a given weight/load.

Of critical importance for a small standard like a Graphic is lens balance.
If it's very front-heavy, you'll stress the front standard, possibly beyond its carrying capacity.
A lens that's well-balanced over the lensboard will put much less stress on the assembly.

You can get a good idea of the problem by holding a brick in your hand, tucked up next to your chin.
Then fully extend your arm, still holding the brick, and note how much more strength is required.

- Leigh

4-Jul-2012, 10:38
I will plan on using it with the lens' focusing mechanism racked as far back as it can go to help balance the weight, provided that doing so leaves enough room on the rails for a support.

Thanks all!

5-Jul-2012, 19:56
I recently had a Pentac mounted on a CNCed SK Grimes board and it was well worth it, they made the flange as well and now everything looks very clean.

Material wise it definitely looks more substantial than the normal graphic boards but I'm sure the normal boards will work well. Its just a matter of reducing the strain on the front standard like you described.