split before or after base grind

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o.ahlgren
Posts: 38
Joined: Thu Feb 06, 2020 10:48 pm

split before or after base grind

Post by o.ahlgren »

my first (and only build so far) was a splitboard that turned out pretty decent.

on that one i did the split before the base grind. it turned out alright, but i'm wondering if doing the split prior to the
base grind would facilitate better odds of getting the two bases even?
JSquare
Posts: 119
Joined: Fri Sep 14, 2012 1:59 pm
Location: NH

Re: split before or after base grind

Post by JSquare »

Congrats an your first build!

It might be helpful if you shared a few more details regarding the design, process, and any issues you're trying to work with. How'd it go? Anything that makes you ask the question? maybe even a photo or two? I'm not sure i understand your question just yet.
o.ahlgren
Posts: 38
Joined: Thu Feb 06, 2020 10:48 pm

Re: split before or after base grind

Post by o.ahlgren »

oh yeah, apologies for being so vague.

My first build was a 163 splitboard, powder-oriented.
Set-back camber between the feet, long rockered nose, short rockered tail.
315 tip
260 waist
305 tail
Bamboo core
Ash veneer top sheet

It turned out a bit "dull" and too soft. My core thickness profile was 2.5 - 6.5 - 2.5. I used 25oz glass.

I made a cutout in the base for the inner edges and left space for the sawblade. So I pressed (vacuum) the whole board as a solid.

After pressing and having trimmed the flash, I basically immediately made the split (cut it in half).
I then handed it in for a base grind and a wax. Now, my fear was that they'd grind the two skis differently, leaving me with different thickness on each ski (which would be noticable in ride mode only.) HOwever it turned out pretty good, but for this next one I think I'll make the split post base grind just to eliminate the risk of them grinding them differently. Or maybe this risk is super small?

How do you guys do it?


Some pics of the first build.

Not so happy with the finish on the top sheet. I didn't wet the top side with expoxy so had a lot of dry spots. Tried sanding it down a lot but got very (a bit too) close to the glass. Also didnt expect the base material to be transparent.
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mammuth
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Location: somewhere in the alps

Re: split before or after base grind

Post by mammuth »

Well, the edges are the "fence" for grinding. If you base(s) are flat they halves will be the same, cutout before and grinded after.
Tom
o.ahlgren
Posts: 38
Joined: Thu Feb 06, 2020 10:48 pm

Re: split before or after base grind

Post by o.ahlgren »

thanks mamuth, good to know.
mammuth
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Location: somewhere in the alps

Re: split before or after base grind

Post by mammuth »

Just one thing. If the guy on the grinder is grinding one side like crazy and the other side not, well then there can be a difference. But then you need another skiman or your base is not flat ;) And we are still talking about 1/10th(s) of a mm.
Tom
JSquare
Posts: 119
Joined: Fri Sep 14, 2012 1:59 pm
Location: NH

Re: split before or after base grind

Post by JSquare »

Beautiful board. Nice work.
100% agree with Tom's comments so far.
One thing-- if you have any warp in your base side to side, cutting down the middle would help limit the amount of material you need to get it flat.
Generally-- if you like your result, i'd say roll with your process.
o.ahlgren
Posts: 38
Joined: Thu Feb 06, 2020 10:48 pm

Re: split before or after base grind

Post by o.ahlgren »

Thanks for the comments guys.

I’ll stick to my current process.
kFergie
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Joined: Mon Jan 25, 2021 7:02 pm

Re: split before or after base grind

Post by kFergie »

Looks awesome, nice work! I am in the process of building a splitty myself and have a question about how you did your core. Did you make a recessed cut-out in the core so that it lays down flush with both the inside and outside edges? Or just leave the core flat?
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chrismp
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Location: Vienna, Austria

Re: split before or after base grind

Post by chrismp »

It is best practice to cut a groove (often referred to as edge rabbet or rebate) into the core to make space for the edge tang thickness. For splitboards this should be done for the inside edges as well.

With some softer woods, you might get away with not cutting this groove. However, not doing this might run you into troubles with base flatness.
kFergie
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Joined: Mon Jan 25, 2021 7:02 pm

Re: split before or after base grind

Post by kFergie »

Thanks chismp, I thought that would probably be the best practice to avoid uneven pressure distribution during the press, but I don't exactly have the best tool to do the job, so I was double checking before committing to doing it
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chrismp
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Re: split before or after base grind

Post by chrismp »

Most people cut this groove with a router. Either a handheld one or on a router table.
o.ahlgren
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Joined: Thu Feb 06, 2020 10:48 pm

Re: split before or after base grind

Post by o.ahlgren »

just pulled my split out of the press. i only recessed the outer edges and not the inside ones. however i used very soft woods in my core (poplar and paulownia) so my base came out very flat. you can however tell on the top surface that the centerline of the based hast lifted slightly.

i will make a router jig to be able to use handheld router to make the inside edge rabbet for my next press and compare.
mammuth
Posts: 449
Joined: Tue Oct 28, 2014 3:48 am
Location: somewhere in the alps

Re: split before or after base grind

Post by mammuth »

inside edge is easy, you just need something straight were you can push your router along
Tom
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