Rega spindle too short

I have a Rega Planar II and I have recently upgraded the platter to an Iron Audio acrylic platter. The table sounds great, it seems to have a more refined and deeper soundstage. The only problem, if it is even a problem, the spindle from the subplatter only sticks out about 3/8" and after I put the mat on I only have about 3/16" above the record. I am wondering if anyone else has encountered this and if so is there an upgradable sub platter with a longer spindle? Thanks in advance.
It isn't a problem unless you want to use a clamp in which case there's not enough spindle to grab onto. The Regas are challenged that way anyway which probably suits Rega's Roy Gandy just fine. He enjoys scoffing at anything he can manage to write off as superfluous.
The Rega spindles were a little short to begin with. If the new platter is thicker than the original platter, then yes, you will be left with virtually no spindle sticking up. If the record can centered and you're not going to use a clamp, it should not be a problem.

Congrats on your new platter. Are you still using the felt mat on top? Try removing the felt mat and see if you like the sound. YMMV
with a vinyl platter you should not use the felt mat. That may help a little with spindle height, and in my experience more than a little in sound quality. As piedpiper says, shouldn't be an issue if you don't intend to use a clamp.
BDgregory would be correct, however the Iron Audio acrylic platter does not have a LABEL recess machined into the top surface so if you do not use a mat of any sort, the record will not sit flush with the playing surface. Iron Audio recommends the use of a mat.
I am still using the felt mat,it is rather thick, I have been looking for a new one, any ideas? I laid a record directly on the platter today, but as Frank said, since the platter does not have a recess for the lable the record does not lay flat.
however the Iron Audio acrylic platter does not have a LABEL recess machined into the top surface so if you do not use a mat of any sort, the record will not sit flush with the playing surface. Iron Audio recommends the use of a mat.
bummer. The problem with going to another thinner mat is it may not provide adequate label relief. Other mats like the Sorbogel. Acromat, or Ringmat are thicker (I think) so will compound the problem. I recall seeing somewhere a replacement spindle for Regas that are longer to accommodate a a thick acrylic platter. I'm not sure where to find one or what they cost, but I would imagine they're pricey.

The options I see for you are 1) buy the extended spindle, or 2) scrap the IA acrylic platter in favor of a Funk Acroplat, or 3) try a thinner felt mat, or 4) live with the mat you have.

Personally, I would buy the funk acroplat.
I might have to check into that extended spindle, I really don't want to scrap the IA, I got a really good deal on it, and I think it sounds great. I will however check into the funk acroplat, to see what it is all about, ie $$$. I am into great sound for low dollar. Thanks.
You could try making your own mat out of something you could cut out a relief for the label. I wonder how difficult it would be to take the platter to a machinist to turn a relief in it. Bad design choice on the part of the Iron Audio.
"Bad design choice on the part of the Iron Audio."
They would have to raise the price in order to include the label recess.
I played some records today without the felt mat, and it sounded great. Before with the mat my speakers sounded really bright, to the point where I could only listed for short periods. Without the mat the lows are alot more pronounced, and the highs are alot more mellow. I was wondering what would be the downfall of not having the recess, because I don't think that I will be puting the mat back on soon. Piedpiper has me thinking about getting the recess cut by my brother who is a machinist, how deep would the recess need to be? and do you think that would be a good idea?
.010 - .020" oughta do it. If forgoing the felt reveals enough of the spindle to use a clamp, you'll want to use a spacer of about 1 1/4" in diameter that fits over the spindle and protrudes above the level of the platter another .010" or so, depending on the record and how much spindle is available. If you can manage it, you'll like the result.
I was wondering what would be the downfall of not having the recess, because I don't think that I will be puting the mat back on soon.
I believe that the idea behind acrylic platters is that the impedance of acrylic is very close to that of vinyl, and with the LP placed directly on the platter surface and clamped, results in an effective LP thickness equal to the LP plus the platter (ie ~ 1 inch). Lacking solid contact you're not receiving this benefit.

That's the theory (and it's better explained in various artical on the web). My own experience is that placing the LP directly on the acrylic sounded profoundly better than with a mat. It also sounded better than my other table that had an alloy platter with felt mat.

I added a Funk Achromat to my table (which already has a 1" think acrylic platter). The Achromat impedance is supposedly perfectly equal to vinyl. While the spindle is too short to use the clamp now, the LP lays so perfectly flat on the Achromat that I think the clamp is superfluous. The sound is even better than with the LP clamped directly onto the acrylic platter. Further, I don't have to hassle with the clamp.

As for having the relief machined, if it were me I'd be tempted to do it - the only reservation I would have is whether the machining is done such that the platter remains balanced. And, not knowing how the IA platter is constructed, whether the machining could affect the structural integrity. And finally, if you ever get to the point you want to sell off your platter for an upgrade, the machining may diminish the resale value.

that's my 2 cents . . .
I also agree about diminishing the resale value of the platter. How thick is the Acromat, I know I could research it, but I don't see the harm in asking. Like I said the sound with album placed directly on the platter is at least 75% better. Without the mat and record I have exactly 3/8" sticking up, would that be enough for the acromat?
The benfeit of the recess is the same regardless of the platter material. Snug record/platter mating is a very basic no brainer. It is a major factor in just about every aspect of the sound. Consequently, IMHO, clamping is major. I was just at Musical Surroundings listening to the $100k Clearaudio Statement table that uses a ring clamp as well as a center clamp. Even with this MASSIVE assault and its center clamp, the difference was not subtle when the ring clamp was added. Even with the Rega and it's felt mat the improvement was noticable when using the clamp from my Maplenoll as a record weight lending more transparancy, solidity and body.
the Achromat comes in 3mm and 5mm thickness. the 3mm mat setting on your IA platter may be the ticket. It provides the label relief w/o touching your platter. The 5mm may also work, but that would only leave 1/8" of spindle to center your LP.
I did do a google search on the achromat and like what I am learning about it. I am going to purchase the 3mm just to be safe. The way I figure it, I already have 5/8" of acrylic. I figure that all I really need is a label recess, so the 3mm should be good.