MiKro

16 hours ago, henrim said:

I thought I’d test first with a sewing machine servo motor I have. It has a driver for speed control and can be operated with foot pedal. Although it may be too noisy, it’s an easy solution for testing. 

Also the 750w motor is an overkill as I’ll make the baffle out of EPS foam, which doesn’t weigh much.

Anyway foot controlled speed is something I really want to try. And it would be great if I could make the thing to return the baffle to the front position when spinning stops. I can’t do that with the controller I have but if I change to a closed loop motor I’ll use a controller I can program freely.

 

@henrim, I would think that if you have a sewing machine motor, say a Consew CSM 1000  or similar and have maybe the needle position set.  If you enable the needle stop up or may be down to coincide with the baffle pointing out that would suffice. I hope that makes sense? You may have to have the actual positioner for that as well? That would be an add-on to the motor as a clutch I think.

mk

@Stu., I do have a question for you. Did you use metal inserts in the wood to screw down the linear rails and bearing blocks?  I have a friend, whose son  is wanting to build a Plywood CNC after seeing yours. Something I told him about last year was an option and keep cost down for now. DUH!! LOL!!

MK

Good for you on this build, at least you used decent linear rails and ball screws to start with. The Ply frame will give good service for wood working and also will give you a chance to really evaluate the CNC need and usage.  The accuracy may suffer some  due to the ply but with wood should be of no real problem. Make sure the Ply is sealed well even though it is painted.  Kudos!!!

ps I would move the electronics though as wood dust will get to it where they are  now.

MK

I play them to make sure all is well, then sell them. Have yet to keep one for me. Also sold all of my factory guitars. There is one that I sold I wish I had kept though. That was my GOTM win in Nov 2008. I miss that one.

mk

9 hours ago, mistermikev said:

all good info mike.  I have wondered about that (one side open) - I see that grizzly makes one that is supported on both sides but uber expensive.  the cnc is def a great tool for it... I just find the planer to be pretty handy esp for anything bigger than my bed.  very much appreciate the insight!!

Mike,

I used to have the pleasure in having access to a friends wood working shop anytime I needed it , had my own key to the shop, about 20k sq ft. He had a drum sander to die for.  It would handle a 6ft wide piece and would go down to a thickness of 1/8".  It had roller in feed and out feed tables that were 12 ft long each.  LOL!!

A tornado took out the shop a few years back and he retired. Oh well.

MK

53 minutes ago, mistermikev said:

hmm.... have oft thought of a thickness sander... but not really interested in spending the kind of money they cost given the amount of application so have been holding out for a while on one.  so... when I hear you say it was torture I want to know more.  was it issues with tracking?  I'm told all of them have issues there.  further... if I take small bites on my planer on moderately figured wood I get a good finish which makes me wonder if I'd be happy at all with a drum sander.  I understand that with the dewalt (735?) you get a speed control and supposedly leaves a finish ready surface so... maybe that's a better buy?  

my planer is just a $100 craftsman with good brand new blades.  

Mike, the tracking on mine was never an issue. The tripping of the breaker on it when I took more than 1/32" was a problem. Also keeping it parallel was an issue as most have only one side closed and the other open so they can do twice the width. I found that my 735 could do most of what I wanted to do, The CNC was also invaluable as was just good hand sanding.

MK

I got rid of my thickness sander. A Jet and it was torture all of the time. I still have a thickness planer that is used maybe twice a year only on things for the house. I do have a CNC router and use that for surface planing guitar wood. The use of a router on a sled would give you almost the exact type of finish. The hold back on that is you cannot control the feed rate consistently like you can with a CNC. That being said, using a router sled is a good idea and least expensive. Maybe adding a lead screw to that mix similar to a lathe on the long axis with a handle and even a more consistent feed rate could be achieved. Use at maximum a 1" to 1-1/2" dia bit at say 10k-12K max RPM for that purpose and taking shallow cuts. 

Just my 0.02 cents on this matter.

mk 

15 hours ago, mattharris75 said:

Did you ever get this thing finished, Mike? Would love to see some finished pics if so!

No Life set in, and I have it partially done it is on the projects list  though.

mk

On 9/9/2022 at 8:20 AM, Wardo said:

Thanks mk for replying. I can't even find a schematic for the poweramp section. Preamp is the same. Did you ground the resistor to the back of the pot? I only see two wires in the little board you made.

Thanks again!

No it is floating just like the resistor it replaced. One of the resistor ends terminates to ground originally. The pot makes a variable resistor, the fixed resistor is in case the pot fails then it fails hot which is what you want.

mk.

You can always use a small soldering torch for the wiring.

mk

3 hours ago, Wardo said:

Hi, thanks for detailing this so well! I want to add a bias to mine X60B, but there is so much contradictory information out there and in my limited knowledge, the way you did it makes the most sense to me. But I was wondering, did the values you use work? And if you don't mind, could you please explain or show a photo of the back of the little bias board you made? I'm just not sure what lugs on the pot go where and did you ground the 47k resistor to the back of the pot? Thank you!!!

I would need to see the schematic for your Amp, as far as the bias board just look at the schematic that is posted along with it. I do not have a picture of the back side.

mk

Been using steel pins for years Mike. I have 1/4" mainly. you just have to make sure they are not in the way of any cuts as a router bit will suffer big time if it hits it. If an end mill hits it it may or may not do well depending on DOC, end mill type ,  etc. LOL.

It is good info to know though.

MK

So Mike, if this is a fretless Bass why the fret slots? I did not read the previous if it was stated there for whatever reason?

MK

Congrats on the GOTM Win Mike.

mk

2 hours ago, Djstatix said:

Your board looks like a 4C mine is a 4B.  Comparing to schematics.

any idea why r127 has two resistors in series?  C2 has a leg lift with a resistor in series too.

 

No clue unless someone has biased it before? Was it set up originally for EL34 power tubes and changed to 6L6? That may be the reason as well. Also not knowing off of the top of my head what the resistance should be on the schematic, maybe they put them in series to get the correct resistance as they did not have the right one?

I am only guessing now though.

mk

1 hour ago, Djstatix said:

Awesome!  Thanks for the help.  I have the 6L6’s installed.  I’ve seen where people installed the Pot on R127 but R126 makes more sense looking at schematic.

I had a long discussion about that very thing with Rob R as you said many put it at R127 and I was not positive. Rob R thought I was on the right track as well. LOL

mk

13 hours ago, Djstatix said:

I can see the board and resistor.  That potentiometer, where did you get it?  Looks like r126 is the insertion point.

It is a trimpot that I had. Yes the insertion point was where R126 would be. On the schematic for the 1986 version may be different? Also not sure what tubes you use? if 6l6 then my values may not work as I was using EL 34 as my power tubes. It is a Round Trimming Potentiometer 1/2watt most likely I got it from Jameco or digikey.

One more thing the Bias value shown on most of the schematics is wrong. Since this is a fixed biasing scheme on the cathode side, you are doing all 4 tubes at once not each individual tube. like many amps. Also most Carvin amps were biased towards the cold side .

mk

49 minutes ago, Djstatix said:

I’m interested in the bias board you made.  Any help with parts used and pics would be nice.

They are posted in the first page of this thread. Very easy to make. Post number 4 in the thread. BTW circuit was checked and verified by Rob Robinette

mk

Finally managed to get back in the shop today. Got the slots cut for the new stripes in the top as I am trying to salvage it. ugg!!

MK

8 hours ago, RVA said:

I was going  to make a jig for my bandsaw fot the scarf joint cut, but it seems like a miter saw is a better option.  Thoughts?

While a miter saw is accurate it does not accommodate the angle you need without making a jig for it.

mk

Here maybe this will help.

mk

Lapsteels are cool. Did this one a while back for a friend.

mk

Looking good John. 

mk

25 minutes ago, Bizman62 said:

My eyes like the proportions of the middle one best.

me too

The beauty of this forum is no matter how long one has been at this game, there is always someone to bounce ideas off of. Thanks!!

MK

11 minutes ago, Bizman62 said:

At least your imagination is working! That looks much better than the broad stripes. And it still is an "easy" fix to make.

Just to feed some more wood into the fire, how about this idea: put in the broad EIR stripes but inlay a strip of the curly maple within. Maybe even thin accent stripes around the curly stripe?

>snip image<

 

Yep that may work as well. Here is the idea using the center Larger maple and out stripes. I think  instead if EIR will use the mahogany instead as this will lend to the finish of the body better.

Image for stripe size comparision. left is 1" outers, right is 0.75" outers and mid is 0.875"

mk