[How do I?] Seeking Assistance With Jig-machine Build

[John Hasler]

I have no direct knowledge with a large thin shell made out of segmented wood. But I would suspect that changes in ambient humidity would play a large roll in trying to mess with that 13.875 critical dimension, even if the wood was sealed. You have that dimension carried out to the 0.001”. That would be an interesting challenge if made out of any type of material! And using the most elaborate machinery. And metrology standards to trace your findings. I commend your efforts.

I suspect that 13.875" really means 13 7/8" +-1/16" .

 

[auto.pilot]

Follow-up question regarding the steel platforms... I went on a hunt for suitable material and quickly found many unfamiliar terms, numbers and alphabet soup. what should I be using?

Thank you in advance for all comments

 

[auto.pilot]

I suspect that 13.875" really means 13 7/8" +-1/16" .

No, it means 13.875. the shells are quite thin and and are also sealed, so humidity changes do not impact the overall diameter.

I very much appreciate all of the comments and suggestions about glue-up methods and ply versus stave construction. I have made and sold many many drum shells and have built custom drums for several years. My reason for posting was to develop quicker and more accurate cutting methods, not to debate the shell construction.

 

[chips&more]

No, it means 13.875. the shells are quite thin and and are also sealed, so humidity changes do not impact the overall diameter.

I very much appreciate all of the comments and suggestions about glue-up methods and ply versus stave construction. I have made and sold many many drum shells and have built custom drums for several years. My reason for posting was to develop quicker and more accurate cutting methods, not to debate the shell construction.

Maybe just me, but if you are making money on other people’s ideas from the HM. I find that awkward. Maybe you should be donating money to the HM.

 

[auto.pilot]

Maybe just me, but if you are making money on other people’s ideas from the HM. I find that awkward. Maybe you should be donating money to the HM.

Excellent advice as well. I donate to a handful of forums and I believe that I have donated to this one as well. I can't really recall when or if I did that. however I will make a donation to this forum within the next week or so.

 

[auto.pilot]

Maybe just me, but if you are making money on other people’s ideas from the HM. I find that awkward. Maybe you should be donating money to the HM.

Thank you again for the excellent suggestion. much to my surprise I was able to make a $50 donation using my cell phone and PayPal. Great forum!

 

[John Hasler]

Maybe just me, but if you are making money on other people’s ideas from the HM. I find that awkward.

Doesn't bother me in the slightest. It's not like it's money I would have made. Ideas are free. Work costs.

 

[Tony Wells]

General purpose steel for fabrication of plate items is most easily obtained as A36, which is a low carbon, fairly soft material available in a variety of thicknesses. Most common is plate, out of which virtually any shape can be fabricated, given the ability to cut and weld. It would be my choice for fabricating a foundation for a machine such as you want to built. Couple that with other common shapes such as square and rectangular tubing, angle, channel, I and H beam, etc, and you should be able to plan out a fairly stout machine without much actual machining.

 

[karim]

I'd stay away from any suggestions regarding modifying the stave assembly/glue-up. All you'd be doing is pushing the need for precision earlier in the process and increasing your production time (i.e.: if the staves are pre-contoured, then the glue-up step becomes a high-precision affair, where it wasn't before—you haven't gained anything in efficiency).

On the live-cutter front, have you considered using rotating drum sanders with very coarse grit? Sort of a surface-grinder approach for wood You could take the entire height of the shell down at once (here I mean the length of the drum shell measured along its axis—I don't know the right term). Then you wouldn't need the "cutter" to move in the Z-axis with any precision... that movement would only be for positioning. You'd slide the sanding head into the shell so that it extends passed the bottom and top, then lock the Z in place. Then with he shell turning and the sanding drum turning, you only need to apply enough force in the X-axis to engage the grit's cutting action, and you could do the whole thing with depth-stops instead of any kind of precision feed. You may find that you don't actually need the shell rotation to be powered at all, as long as the rotational axis is fixed.

Might take some trial and error to find the right balance of cutting speed and grit to avoid tearout, but once dialed in, your only consumables would be the sanding drums.

 

[auto.pilot]

I'd stay away from any suggestions regarding modifying the stave assembly/glue-up. All you'd be doing is pushing the need for precision earlier in the process and increasing your production time (i.e.: if the staves are pre-contoured, then the glue-up step becomes a high-precision affair, where it wasn't before—you haven't gained anything in efficiency).

On the live-cutter front, have you considered using rotating drum sanders with very coarse grit? Sort of a surface-grinder approach for wood You could take the entire height of the shell down at once (here I mean the length of the drum shell measured along its axis—I don't know the right term). Then you wouldn't need the "cutter" to move in the Z-axis with any precision... that movement would only be for positioning. You'd slide the sanding head into the shell so that it extends passed the bottom and top, then lock the Z in place. Then with he shell turning and the sanding drum turning, you only need to apply enough force in the X-axis to engage the grit's cutting action, and you could do the whole thing with depth-stops instead of any kind of precision feed. You may find that you don't actually need the shell rotation to be powered at all, as long as the rotational axis is fixed.

Might take some trial and error to find the right balance of cutting speed and grit to avoid tearout, but once dialed in, your only consumables would be the sanding drums.

What a great idea! the shell interior needs to be smooth as well, and parallel to the exterior. I can't envision an internal sanding method. my biggest concern would be achieving consistent results both interior and exterior while using two different methods. need to mull this around because your suggestion is excellent .

Thanks!