Ski Builders Forum

Great progress man! Keep at it )

Saw your skis today at Sugarloaf. Looks very good.

MadRussian wrote:Saw your skis today at Sugarloaf. Looks very good.

Glad to see they are getting the fellow builder thumb of approval! Always a tough crowd to impress

If you come up this way often give a shout. Sugarloaf is my home turf. Would love to make some turns or a grab a beer with you!

That goes for anyone!

You mogul guys,

A 0.5" 4 flut carbide bit is where it's at. Currently using an upcut, but going to try a downcut. The only thing with an upcut is you need to MAKE SURE YOUR BOARD IS 100% SECURE.

As in, the entire core has to be held down. Not just certain points. Had a couple pieces of sidewall get sucked up becuase I didn't make sure they were held down well. This was also cutting finish passes at 100IPM so the machine is material hungry.

However I found rough passes at 180IPM on a 126-108-110 core was done in 8 minutes. (8:02 to be exact). Finish pass took about 15. I was playing with speeds on that.

Chris how are you bonding your sidewall?

vinman wrote:Chris how are you bonding your sidewall?

Super secret sauce!

But no, the same as everyone else.

It wasn't a matter of the sidewall to the core (it pulled the entire core off the table, sidewall still attached). It was just a function of simply being lazy and not running a dab of hot glue where I should have to secure it to the table. I need to rework my vacuum table. There is a couple things I'd like to change to get better hold down. A vacuum table with a series of patterns shaped like a core is next on my list

amidnightproject wrote: I need to rework my vacuum table. There is a couple things I'd like to change to get better hold down. A vacuum table with a series of patterns shaped like a core is next on my list

I have the same opinion. I did a 2" grid pattern and I'm not happy with it at all. my limiting factor is suction on my table. Your idea with patterns is the same route I was going to go. take the ski shape and inset it a few mm and cut it into the table then channel it to my central vac area.

4 flute? Are you using a end mill bit? square or rounded corners? You've spiked my interest on this, more flutes increase chip rate. http://www.mcmaster.com/#3066a21/=qnctr3

skimann20 wrote:

amidnightproject wrote: I need to rework my vacuum table. There is a couple things I'd like to change to get better hold down. A vacuum table with a series of patterns shaped like a core is next on my list

I have the same opinion. I did a 2" grid pattern and I'm not happy with it at all. my limiting factor is suction on my table. Your idea with patterns is the same route I was going to go. take the ski shape and inset it a few mm and cut it into the table then channel it to my central vac area.

4 flute? Are you using a end mill bit? square or rounded corners? You've spiked my interest on this, more flutes increase chip rate. http://www.mcmaster.com/#3066a21/=qnctr3

I was thinking exactly that only not cutting it into my table spoil board. I was going to cut another piece of MDF that will cover 2 of my 4 vac sections. Put another grid on the bottom of that smaller piece, with holes drilled slightly smaller then my core profile.

Hopefully I explained that alright. I just confused myself writing it!

I am using a 4 flute end mill. Square corners. Exactly like the one linked to on McMaster. It's the bees knees.

I like your idea. my only concern with it is will it lay "Nuts Flat" on the spoil board? I guess the vac will pull it down tight. The modular end of your idea is right on and I like it a lot. I wish I thought of it.

I like bee's knees. might have to try it. I was going to go with the rounded corners, because I was thinking it will reduce the chance of tear out.

It's strange that your core lifts from the vacuum table. My table has three vacuum cleaner motors and a hole spacing of about 3cm whith 5mm diameter holes. I just place the core on the table cover all the open holes with foil or packing tape and it works like a charm. My cnc chews away at the core with a 20mm two flute straight bit running at 250 ipm, 50% stepover and 1.5mm depth of cut per pass.

Hey chris for some reason my stepover doesnt work. I have it set to different percentages but it doesnt actually do it. Any idea what im missing in that cam?

Hey chris for some reason my stepover doesnt work. I have it set to different percentages but it doesnt actually do it. Any idea what im missing in that cam?

Did you enter a tool diameter in the tool manager? I never really paid much attention to whether the stepover actually changes when I enter a new value...will have to check on that.

skimann20 wrote:I like your idea. my only concern with it is will it lay "Nuts Flat" on the spoil board? I guess the vac will pull it down tight. The modular end of your idea is right on and I like it a lot. I wish I thought of it.

I like bee's knees. might have to try it. I was going to go with the rounded corners, because I was thinking it will reduce the chance of tear out.

Only one way to find out? haha

I need to re-surface my table anyway. I fudged it up when I had all that z axis drifting. sucks.

I think i'm going to give this method a shot. Might as well give it a try. All it'll do is waste $8 of MDF haha

As for the round bit vs square, I haven't had any issues with tear out. Just the bit pulling the material off the board. I thought of trying one as well. The machine shop only had square on hand so that's what I bought. It makes sense though that a rounded endmill would in theory help eliminate tear out.

chrismp wrote:It's strange that your core lifts from the vacuum table. My table has three vacuum cleaner motors and a hole spacing of about 3cm whith 5mm diameter holes. I just place the core on the table cover all the open holes with foil or packing tape and it works like a charm. My cnc chews away at the core with a 20mm two flute straight bit running at 250 ipm, 50% stepover and 1.5mm depth of cut per pass.

I don't have that much vacuum power yet!

I need to get a filter for my spare shop vac and hook it up. Been researching what to use to generate a better vacuum. Everything I've read comes back to using large fans in custom built enclosures. Any experience with that?

I'm cutting with a 12.7mm bit, 180ipm with 50% stepover and 4mm depth per pass on roughing. 2mm on finish pass.

The finish pass is where it got me. I need to increase my hold down power for sure!