I'm making a batch of keeper bars next weekend

[corduroyew]

Next weekend I'll be making a new batch of keeper bars. They will be milled from the British steel grade En3B which ranges from 1017 to 1022. This batch matches American grade 1018. It is cold rolled and surface ground.

This batch of steel will fall within these specs
Carbon 0.15
Manganese 0.60-1.0
Phosphorous 0.05 max
Sulphur 0.05 max

They were able to tell me the exact carbon content for this batch and the other specs listed are just their standard tolerances.

The steel supplier I’m using has a minimum order so I’m getting enough steel to make around 4,000 keepers. I thought that since I’ve got the materials I might as well make some extra and sell them off. The price will be $1.25 USD (60p if you pay in Pound Sterling). Shipping will be a flat rate of $2.00 USD or 1 quid for the Brits.

If you are interested let me know.

[corduroyew]

my standard dimensions are 2.228" long x 0.196" wide x 0.125" thick with 50mm hole spacing but if you need a different spacing or size let me know and I should be able to do it for you.

[JGundry]

Can you post a photo of one of your finished keeper bars?

[corduroyew]

The steel is scheduled for delivery on Friday so I'll get pics of the finished product on Saturday.

[J S Moore]

If they are milled rather than punched I am definitely interested.

[corduroyew]

They are cut with a bandsaw, ground, then holes are drilled with my drillpress that I modified to to be accurate to .02mm which is about the same accuracy you get from most micro mills.

[corduroyew]

I have some pics now. I'm not good with a camera so this is the best I can do. I put my keeper side by side with one of the Asian punched keepers you get in kits. I'm not going to say who the punched keeper came from but every punched keeper I've ever had my hands on was of a similar quality.

Mine is the one that has flat surfaces and round holes. The punched one has the oval holes and is shaped like a loaf of bread.

http://www.rockmonkeyguitars.com/images/keepers.jpg

http://www.rockmonkeyguitars.com/images/keepers2.jpg

http://www.rockmonkeyguitars.com/images/keepers3.jpg

[Electricdaveyboy]

Hello Chris,
looks nice.
Did you have the chance to hear the keeperbar?
best
david

[corduroyew]

Not yet. Hoping to do that tomorrow.

[Possum]

how are you doing the drill hole spacing? I'm drilling holes on a mill and made a drill hole guide which is kind of slow and clunky to use but works sort of.

[corduroyew]

I have an X Y table with a vice on it. I replaced one of the metal plates with a piece of wood so that it'll compress around the keepers when I close the jaws. This makes it so I can clamp multiple keepers at once without having any slip. If you leave 2 metal jaws in there then you are stuck only being able to clamp 1 keeper at a time. I clamp 2 keepers at once. 1 is already drilled and is used to keep the bit from wandering the other is the keep I actually want to drill. The table that I'm using is in mm increments and 1 full turn equals 1mm so I just have to turn the handle the correct number of turns to get the spacing right.

To speed things up a little I sometime shape a block of metal that is tall enough to cut 5 keepers from. I'll drill that, then slice the keepers off. It's a lot faster that way but I use up more bits too so I tend to stick with 1 at a time.

[Possum]

thanks for the tips, now I'll have to figure out spacing for gibson stuff, I think its 49.2mm but my mill is in inches decimal so will have to figure out this stuff on paper, this should speed this up for me if I can stumble through the math right :-)

[Possum]

Uh, I'm a little bit heavy right brainer here. the hole centers I need to drill are .19375" apart , that part I could figure out. What I'm confused about is my mill indicators on the table are .001" per small mark. There are 50 marks per turn. HOw many turns do I need to do and how many marks after that to hit this measurement? Same thing I need to know for the skip in the middle where the holes are .3875" apart. Any math whiz types here? Embarrassed thanks.....

[corduroyew]

.001” per mark
50 marks per turn
That means .05” per turn.
.19375/.05=3.875 turns

If 1 turn is 50marks and we need .875 turns I think that means we multiply 50 by .875 to find out the number of marks you need.

50x.875=43.75

So I think you need 3 turns and 43.75 marks but I could be completely off. I’m not one that’s good at working it out on paper. I just kinda set it up so that it looks right. Do it, and then check my measurements afterwards and see if it lines up.

[EtLa]

Here is what I figured out

0.19375 /.001 = 193.75 marks
193.75 / 50 marks = 3.875 turns
0.875 turns x 50 marks = 43.75 marks
3 turns + 43.75 marks

0.3875 / .001 = 387.5 marks
387.5 / 50 marks = 7.75 turns
0.75 tuns x 50 marks = 37.5marks
7 tunns + 37.5 marks

[Dave Kerr]

50 * .001 = .050" per turn
4 turns = .200", 6 marks back from 4 full turns is .194"

8 turns = .400", 12 marks back from that is .388"

[corduroyew]

I almost forgot. I got the detailed spec sheet for my steel.

C .15
Si .166
Mn .811
P .007
S .012

I've posted it before but here is your standard variance for 1018

C .15-.20
Si .15-.35
Mn .60-.90
p .04 max
S .05 max


I've tried a couple of the new keepers and they sounds exactly like my last batch did. They have a nice balance that is great for the neck or bridge. They’ve got that goldilocks thing going on. Not too bright, not too boomy… these are just right. That’s what I think of them. I think they are much better than the punched kit keepers as far as tone and because mine aren't deformed from punching, they are easier to fit into place. I’m sure that I'm a bit biased with my opinion but the price is low and so is the shipping cost so you can always get a few now and then get more later if you like them.

[Possum]

after I wrote that, I manged to figure out the same thing by myself, wow. Maybe I'm not so dumb after all :-) This will be cool, using a steel drill hole guide on a mill is a pain in the butt and really slow and not very accurate, not recommended....

[corduroyew]

Thought I'd give you guys one more pic. Here is a keeper mounted onto a bobbin. Notice the very snug fit around the poles.

Here is one of mine
http://www.rockmonkeyguitars.com/images/keepers6.jpg

[Joe Gwinn]

Uh, I'm a little bit heavy right brainer here. The hole centers I need to drill are 0.19375" apart , that part I could figure out. What I'm confused about is my mill indicators on the table are 0.001" per small mark. There are 50 marks per turn. How many turns do I need to do and how many marks after that to hit this measurement? Same thing I need to know for the skip in the middle where the holes are 0.3875" apart. Any math whiz types here? Embarrassed thanks.....First, some preliminaries:

49.2 mm over six poles is 49.2/5= 9.84 mm between poles.

9.84 mm is 9.84/25.4= 0.3874" between holes.


Second, it's 0.050" per turn, or 20 turns per inch. That seems plausible, being a standard thread (as in 1/4-20) so we will assume that it is correct in the following computation:

0.19375/0.050= 3.875 turns. So, go 3 turns plus (0.050)(0.875)= 0.04375= 0.044" on the dial.

For the 0.3874 dimension, it's 0.3874/0.050= 7.7480, or 7 turns plus (0.050)(0.748)= 0.0374= 0.037".


Beware error accumulation. Compute the exact location of each hole, and then convert to added turns and offsets in thousandths. A spreadsheet is very useful here, to avoid errors. Otherwise, the last hole will be way off.

[Possum]

I didn't use milimeters, I used 1 15/16" and my mill is in inches not milimeters. I haven't done one of these yet, what is the best way to avoid error accumulation, I was going to drill the first hole then space it .19375" (well as close as I can using the marks) and do the same for the next hole. BTW there are 10 holes so the spacing is based on there being 11 holes, the middle hole isn't drilled so there's a blank space where that hole would be. So there are 10 spaces between holes so I did the math for 10 spacings or 10 jumps. Make sense? I may look into getting a digital readout for this thing at some point to make things simpler if I keep using it in production stuff....

[Joe Gwinn]

I didn't use millimeters, I used 1-15/16" and my mill is in inches not millimeters. I haven't done one of these yet.If the spec is in millimeters, convert it to inches by dividing by 25.4, but keep lots of digits. Don't try to round it off to the nearest 16th of an inch.

What is the best way to avoid error accumulation? I was going to drill the first hole then space it 0.19375" (well as close as I can using the marks) and do the same for the next hole. Generate the locations mathematically with full precision, and round only after generating all the full-accuracy hole locations.

BTW there are 10 holes so the spacing is based on there being 11 holes, the middle hole isn't drilled so there's a blank space where that hole would be. So there are 10 spaces between holes so I did the math for 10 spacings or 10 jumps. Make sense? So, it's really 11 hole positions, but with one missing hole? If so, it's 10 spaces in 1-15/16 inches, so the spacing is 1.9375/10= 0.19375", and the hole locations are 0, 0.19375, 0.3875, 0.58125, and so on. Round these to the nearest thousandth of an inch: 0, 0.194, 0.388, 0.581, and so on.

I may look into getting a digital readout for this thing at some point to make things simpler if I keep using it in production stuff....DROs are very useful, and speed things up greatly.

[David King]

CNC is very useful and speeds things up even more..

[corduroyew]

There are still a handful of you still waiting for the keeper bars. The parts to my bandsaw are still on backorder so I'm still waiting for them to come in. If any of you feel it's taking too long (haven’t had any complaints yet but wanted to say something before any came up) then I will happily refund your money. Otherwise, I'll get them made as soon as my bandsaw parts get here.

Sorry for the delay

[Sam Lee Guy]

Hi,
would like to try a few of your keeper bars. Standard PAF spacing, against common belief is 49.4mm. Don't know why, it just is. Can you make them this spacing?

[corduroyew]

I can but it'll have to wait until I've got the parts for the bandsaw in. They were supposed to be here a week and a half ago. Every time I call them they say "they should be in tomorrow" and then it never happens. :mad: