LF thoughts on this finger design please

[sleepingdog]

I have reworked the model to make the following changes:

Axle changed to 5/16
5/16x1/2" bearing added to brass finger (not shown in images)
18 ga steel used for scissors
Raise plate bearing changed to 3/32 x 3/16 x 3/32

Going to the smaller bearing on the raise plate caused me to have to put a relief cut on the back side of the brass finger to make clearance for the scissor plate. I didn't feel there would be enough "meat" around the bearing rivet if I cut the plate back enough to clear the finger. Have you guys run into that problem? Ron, I noticed a similar interference in one of the drawings you posted.

I think now I'll prototype one and put together a single string mock-up to test it. I will have to wait for bearings and other stuff to come in, though.

Look reasonable?

Dave

[sleepingdog]

Trying to source rivets for to put this thing together with. Where are you guys buying rivets from?

Dave

[Storm Rosson]

Dave that looks on the money wish I would quit bein a lazy ass and learn alittle of this Auto Desk (Autocad) proggy I got my oldest son when he graduated. I just can't seem to work up the ambition to tackle monster software programs.(I don't use "apps" at least don't use that word instead of program cause it sounds to much like Apple fan boy/genius? bar crap. Anyhoo I think you nailed the finger mod if u don't mind I may use the design when(if) I get around to starting a new build.As for rivets, I used some brass binding screw/chicago screw/sex screw rivet-like do hickeys I found at Ace and also at True Value. Pretty sure they were labeled "binding screw" they're amongst the not so common connectors,and various springs, etc. every Ace and True Value has this same array of wierd crap by the same distributor some of the stores in larger markets have the big boy version of the display/kiosk/wtf u call it,it's my favorite part of the store. I think they come in Stainless too but not completely sure.They kinda cool and easy to work with albeit markedly more expensive than a steel peen type rivet but you only need 10 of'em, seems they were o.80 cents or so.Not gonna break the bank. When u finish the proto and nail it to a board could post a few photos of it in action. I really like actual methodology and measurement so u have actual facts with the numbers to verify them like how much travel the raise/lower fingers and associated parts are capable of so u can know how many half tones up or down the design can handle properly/comfortably without discovering some strange side effect.Gotta go dump....you may have guessed I'm full-o-shit especially today ,later homeboy..S tormy

[maxi19]

I use 'semi tubular rivets' I buy on e-bay.

[sleepingdog]

Wow. Those are some long rivets. Are you using those in the scissors? You must have to shorten them if so.

[maxi19]

Hi Dave that is the only photo I could find as an example the ones I get are 6mm long and are used with washers

[rtp_burnsville]

Nice job on the finger assembly..... This is a great thread.

Thanks,
Robert

[sleepingdog]

Hi Dave that is the only photo I could find as an example the ones I get are 6mm long and are used with washers

Great shots. You can even see the PTFE disk in between the finger plates. I hadn't thought of the washer idea. I like that idea 'cause it means you don't have to buy the perfect length rivet. Looks great.

[Storm Rosson]

That do look nice Ron, what's the diameter of the rivet? Stormy

[maxi19]

Hi Stormy,

The rivet size is approx 6mm x 4.5mm so the imperial size is likely 1/4" x 3/16"
here is a link stateside http://www.brettunsvillage.com/leather/parts/rivets.htm
Zinc-Plated Steel Tubular Rivets