Might I suggest an alternative which is not to cut a hole -- a circle -- in your benchwork or layout. Cut a square, rather larger than the hole will be. Work with a square the same size at your workbench and cut the hole -- the circle -- in that. Because of the angle you work from and the height of the benchwork I think it is easier to cut a perfect square in already existing layout benchwork than it is to cut a perfect circle. And this way you give yourself more bites at the apple if you make a mistake cutting the circle.
Once you get the turntable the way you want it in the square you more or less drop it into the layout. A bit of ground cover will hide the seams. An additional benefit is the greater ease of removing the turntable for maintenance or replacement.
I seem to recall this is the way Diamond Scale turntables come from the factory by the way -- on square mounts.
Dave Nelson
Bruce,
I just recieved the 90 ft. turntable kit. The pit is 1 & 11/16 deep, so you
can probably cut just the foam to hold the table. The motor kit mounting on the
underside is 5 & 5/8 across. So cut the plywood that size. The Bosch blade you
can use is #T318A. It will make a cut about 3 &1/2 deep. The instructions say
to make the pit hole 12 & 5/8. I haven't installed my table yet, but it looks
very easy.
Phil, CEO, Eastern Sierra Pacific Railroad. We know where you are going, before you do!
Here is the template from Walthers for the 90' TT (indexed version). Should be the same as the manual version. Walthers Instruction sheet states to allow for 2 1/4" depth.
http://www.walthers.com/instructions/extras/0933/09330000002840a.pdf
Blind Bruce wrote:Good ideas one and all. I will wait and see if the plywood' hole can be smaller and if not, I will try the doughnut method. If all those fail, I will get longer blades for my Bosch.Many thanks,BB
Good ideas one and all. I will wait and see if the plywood' hole can be smaller and if not, I will try the doughnut method. If all those fail, I will get longer blades for my Bosch.
Many thanks,
BB
If the router is the most appropriate tool, there are router bits that are over 2" in length. Often pricey, but very useful.
Crews
I believe so...I don't recall, but I have a foggy memory of them providing one in the case of the 90' built-up and for the kit. I can't even remember why I elected to measure it out the way I did, but apparently I forewent the template.
-Crandell
Doesn't Walthers include some type of template with their turntable so you can properly size the required hole? I'd definitely wait until I received the turntable to see exactly how much clearance I needed before trying to cut both the 2" foam and the plywood.
Bob
Use a Roto-Zip and one of these:
http://www.westerntool.com/product.htm?pid=455181
Dave
Just be glad you don't have to press "2" for English.
http://www.youtube.com/watch?v=zQ_ALEdDUB8
http://www.youtube.com/watch?v=6hqFS1GZL4s
http://s73.photobucket.com/user/steemtrayn/media/MovingcoalontheDCM.mp4.html?sort=3&o=27
Johhny_Reb gave you very sensible advice. I am not convinced you'll need the plywood holed as well, Bruce, but his idea is the way to go.
Wait until you get the TT, though because the lip is quite capable of supporting the whole shebang, even with a good-sized engine aboard. So, you will measure the outer diameter of the pit where it meets the lip, and the outer lip idiamter tself is easily measured, and you then have about 1/2" of grace to play with in drawing your circle. IOW, you could easily hand draw the circle and get away with as much as 1/2" in error at any one point without affecting the operation or looks of the TT appreciably. I wouldn't advise it, of course, but someone in a real hurry who could draw a reasonably precise circle by hand with a few reference tick marks meaured out for guidance (what I did the first time around) would have no issues later on. As long as there are five or six solid support points scattered evenly under the lip, you'll be just fine.
73
Bruce in the Peg
IRONROOSTER wrote: Long jigsaw blades are available, but you might have to mail order them. Bosch lists some on their web site that are long enough for this http://www.boschtools.com/Products/Accessories/Pages/BoschProductCategory.aspx?catid=98 but I am sure there are others.EnjoyPaul
Long jigsaw blades are available, but you might have to mail order them. Bosch lists some on their web site that are long enough for this http://www.boschtools.com/Products/Accessories/Pages/BoschProductCategory.aspx?catid=98 but I am sure there are others.
Enjoy
Paul
I've seen those at Loews and Home Depot too.
First mark the hole needed for the Turntable. then mark a bigger circle to be cut out. Cut the hole for the Turntable. Then cut the bigger hole in the foam and remove it in one piece. Use this area to cut the Turntable hole in the plywood if needed. Return the foam doughnut to it's place.
"Doughnut" = The larger hole with the smaller hole cut into it for the Turntable.
By cutting the foam bigger then needed it can be reinstalled in its place, but will let you access the plywood to cut the smaller hole needed for the Turntable. And once cut the lager hole can be reinstalled filling in the area around the Turntable and once the surrounding scenery is in place the cut will never be seen.
Johnnny_reb Once a word is spoken it can not be unspoken!
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Wait until you get the turntable, the cut at the surface probably needs to be pretty accurate, but if its anything like the 90' kit turntable only a small part of it protrudes more than 2" so you might not need to do much more than drill a few large holes in the plywood with a hole saw.
Additional thought- If you have a jig saw blade that at full stroke extends NO MORE than your foam thickness you can cut the circle in the foam, remove the foam and then use a sawz-all to cut the plywood.
Then again, perhaps the TT does not drop that far below grade level....may only need a smaller hole in the plywood?
Can you access the bottom with the jig saw or router? If you can you just need to "borrow" a steak knife to finish off the foam.
OR
If you have access to a saw-zall you can do it from the top. Word of warning on this method- the longer the blade the more the cut will deviate from your planned circle. Take it slow and don't force the blade.
My Walthers 90' turntable should be here soon and I will need to cut the hole in my table when it arrives. Once I figure out exactly where the center is, what is the best method to cut it out?
It is 2" foam caulked to 1/2" plywood. My jig saw might not reach through the foam to make the cut. My router bits aren't that long either.
How accurate does this hole need to be? I could use a drywall saw and do it by hand if I have enough tolerance.