| Author |
Message |
    
David Buchsbaum
Registered Member
Username: Beacon14
Post Number: 447
Registered: 10-2000
| | Posted on Wednesday, November 29, 2006 - 2:10 am: |    |
I have designed a cam-based holddown which I would like to try out on my T-tracks for some solid wood slabs I need to plane down. The key is an aluminum core which I know I could machine myself, but I have had very little experience with aluminum, and do not have the time to learn enough to do this right.
So what I am hoping is to find someone who can look at my drawing and whip out a few of these in aluminum, in exchange I'll work out the wood parts and, assuming the whole thing works as well as I think it will, provide each of us with the wood components for a nice set of holddowns. I'll need about 6 now for testing, and would like to end up with about 2 dozen if they work out.
Any takers? |
Shawn Fennell
Registered Member
Username: Conceptmachine
Post Number: 8
Registered: 9-2006
| | Posted on Wednesday, November 29, 2006 - 6:57 am: | |
David,
I would be glad to help you out,im a newbie botter,just bought a used prt 96 still in the process of tweaking it in.I'm a tool and die maker by trade and have cnc machine shop at my disposal send me your mailing add: and as soon as i get a few minutes of spare time ill make you some sample parts.I've been pondering on methods to hold down parts to the sb,its alot different than working with metal,im used to precision vises,magnetic chucks etc...i used all of my funds to buy the sb so a good vacuum table is out of the qustion for the time being.What are some good ways to hold down parts(other than screwing the material to the table)?
---shawn |
Shawn Fennell
Registered Member
Username: Conceptmachine
Post Number: 9
Registered: 9-2006
| | Posted on Wednesday, November 29, 2006 - 7:01 am: | |
Oh forgot to add that if anyone else has any ideas for modification and/or accessories for the shopbot let me know if could be of any help.
----shawn |
David Buchsbaum
Registered Member
Username: Beacon14
Post Number: 448
Registered: 10-2000
| | Posted on Thursday, November 30, 2006 - 9:42 am: | |
This sounds like a match made in heaven... |
David McNutt
Registered Member
Username: Djmcnutt
Post Number: 19
Registered: 3-2005
| | Posted on Thursday, November 30, 2006 - 2:09 pm: | |
David,
When you get these hold downs finished I would sure like to see them. |
Shawn Fennell
Registered Member
Username: Conceptmachine
Post Number: 25
Registered: 9-2006
| | Posted on Friday, December 29, 2006 - 8:12 am: | |
David,
Had a chance to test the clamps yet?
Shawn |
David Buchsbaum
Registered Member
Username: Beacon14
Post Number: 458
Registered: 10-2000
| | Posted on Friday, December 29, 2006 - 9:46 am: | |
the first test pieces are ready to be cut at this moment...stay tuned.. |
David Buchsbaum
Registered Member
Username: Beacon14
Post Number: 459
Registered: 10-2000
| | Posted on Friday, December 29, 2006 - 12:32 pm: | |
First let me say a big Thank You to Shawn as he has come through for me in a big way. The aluminum parts are beautiful and extremely accurate - way better than I could have done without pulling out what's left of my hair. I'm guessing they were machined on a CNC lathe - my digital caliper reads that they are within .001 in roundness and size accuracy. Thanks again Shawn.
The technique definitely works. I'll be playing a little more this afternoon with tweaking the amount of cam action and various materials. Here are a few pics from the first test setup
 |
Gene Buckle
Registered Member
Username: Geneb
Post Number: 37
Registered: 7-2006
| | Posted on Friday, December 29, 2006 - 12:42 pm: | |
That is insanely cool.
Are you going to offer the clamps for sale?
g. |
David Buchsbaum
Registered Member
Username: Beacon14
Post Number: 461
Registered: 10-2000
| | Posted on Wednesday, January 03, 2007 - 2:32 am: | |
OK, here's the working prototype. It takes surprisingly little cam action to generate crushing force at the point of contact.
Since Shawn does not have T-track it makes it hard for me to fulfill my original offer, so I made a version that can screw down to the table or to a jig. I'll probably use these for shorter boards like the one in the picture that don't reach between 2 T-tracks.
The cam generates so much force it wants to move the fence, so I came up with this little "table dog" to secure the other side of the board. You could use these by themselves I suppose - I cut the notch into the backside to make it easier to drive it into the wood with a block and hammer.
Not sure if it will be worth trying to sell. Shawn is supposed to be looking into the cost of the aluminum hub. Drop me an e-mail if interested. |
Shawn Fennell
Registered Member
Username: Conceptmachine
Post Number: 47
Registered: 9-2006
| | Posted on Wednesday, February 21, 2007 - 1:25 pm: | |
David,
Have you had a chance to try the new hubs?
shawn |
David Buchsbaum
Registered Member
Username: Beacon14
Post Number: 479
Registered: 10-2000
| | Posted on Friday, February 23, 2007 - 8:09 pm: | |
Nothing like a little public pressure there Shawn! But you'll have to take a number - it may be another couple of weeks before I can work it in. |
Timothy Newman
Registered Member
Username: Menewfy
Post Number: 21
Registered: 4-2007
| | Posted on Wednesday, May 16, 2007 - 8:04 pm: | |
it has been more than a few weeks now sorry vacation is over.
this is a really nice idea and I am interested in how well it works can you please update us?
tim |
David Buchsbaum
Registered Member
Username: Beacon14
Post Number: 522
Registered: 10-2000
| | Posted on Friday, June 01, 2007 - 12:24 pm: | |
OK thanks for being so patient - I've written a full description as part of my online series here.
I've included files with the specs on the parts so you can hopefully make your own. I'm sure there will be some interest in purchasing the aluminum hubs if so please send me an e-mail. Questions or comments about the functional aspects can be addressed here. |
jack jarvis
Registered Member
Username: Myxpykalix
Post Number: 723
Registered: 3-2006
| | Posted on Friday, June 01, 2007 - 5:31 pm: | |
This looks very cool, but since i can still be considered a newbie, let me ask a dumb question. On some of the top pics on the page it shows what looks like a plenum board with the T tracks embedded minus any spoilboard. It this setup used exclusively for setups where you are not cutting thru the material? If not, how do you keep from hitting the T track? |
David Buchsbaum
Registered Member
Username: Beacon14
Post Number: 524
Registered: 10-2000
| | Posted on Saturday, June 02, 2007 - 12:27 am: | |
Jack, good observation. The T-Tracks are embedded into my plenum and get covered by the spoilboard when the vaccuum system is in use. I tend to use the T-Tracks for jobs that do not require through cutting.
You'd have to be careful using the cams when through cutting close to the edge of the material as you can rout away the structure of the material leaving nothing solid for the cam to push on. |
David Buchsbaum
Registered Member
Username: Beacon14
Post Number: 571
Registered: 10-2000
| | Posted on Wednesday, September 12, 2007 - 10:53 pm: | |
OK, I've finally caught up to where I can spend a few minutes on this, and have received a quote from a local fabricator for milling the aluminum hubs. I'd have to order 100 of each size to get my price below $10 each, which would make a somewhat sizable investment. Frankly it's not worth my time to get into this and pass these along at or near cost, and I'd really rather not buy hundreds of these if only a few people are interested. So I'm trying to figure out how much I'd have to charge and how many I'm likely to sell.
I'm thinking of offering the cams as sets, including the aluminum hubs and Baltic Birch plywood levers, for $25 each, with a minimum order of 4 sets, including shipping within the USA.
Please let me know here or by e-mail if you would want to order a set at that price level, and whether you would want the T-track (bolt down) version or the screw-down version, or both, or whether you'd rather just buy the hubs and make your own levers. I'd probably have to get orders for at least 50 sets before it would be worthwhile. All constructive feedback is welcome. |
Peter J. Meacham
Registered Member
Username: Pete
Post Number: 100
Registered: 1-2001
| | Posted on Thursday, September 13, 2007 - 9:42 am: | |
David - are you going to offer the table dogs as well? Seems like a good addition to the product line and a package deal could include the dogs. Thanks, Pete. |
Gary G. Campbell
Registered Member
Username: Islaww
Post Number: 88
Registered: 4-2007
| | Posted on Thursday, September 13, 2007 - 4:43 pm: | |
David..
I was thinking I was going to be one of few that took advantage of your cams. Nice to see this thread reopened. In case any one has any questions, I purchased a dozen of the hubs and they work just great. I used PVC for the handles for a little softer edge. Shawns machinery is very high quality. Thanks again to David and Shawn.
Gary |
