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Cutting styrene strip
thehermit
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Manitoba, Canada
Joined: August 27, 2007
KitMaker: 274 posts
AeroScale: 63 posts
Posted: Thursday, December 29, 2011 - 02:35 PM UTC
Does anyone have one o those Chopper units from North West short Line...? I was wondering if someone did, they might be able to post a few close-up pics of same as I want to try and build my own. I'm not cheap, but I spent waaaaay too much for Christmas on "other" modeling goodies...my bad...!!

I'm looking for the first version of the "Chopper", built on what looks like a pce of MDF...?

Thanks
fitzgibbon505
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Colorado, United States
Joined: May 20, 2002
KitMaker: 99 posts
AeroScale: 0 posts
Posted: Thursday, December 29, 2011 - 11:29 PM UTC
While it is definitely possible to make your own, I would highly recommend the Chopper II. The rigidity and replacable cutting mats will make it worthwhile over the long run, and the size makes it very handy. I had originally purchased the Chopper III. I was extremely disatisfied with the threaded inserts for the clamps, which tended to pull out. I now have all the hardware mounted on a new base made from aluminum plate, and it works very well. If you do decide to build one from wood, I would suggest using blind nuts for the threaded holes so they will not pull out.
thehermit
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Manitoba, Canada
Joined: August 27, 2007
KitMaker: 274 posts
AeroScale: 63 posts
Posted: Friday, December 30, 2011 - 01:44 PM UTC
[quote] While it is definitely possible to make your own, I would highly recommend the Chopper II. The rigidity and replacable cutting mats will make it worthwhile over the long run, and the size makes it very handy.

Thanks for the note Jim. I put together a prototype, but damned if I can figure out the proper angle for the blade...!? When I drop the handle down the blade connects the plastic strip almost flat and you CANNOT cut through the darn thing...!!! After much consternation and "blue words", I decided I will take your advise and wait till Feb (birthday) and get a Chopper II...!

Regards, Laurie
casper
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Nelson, New Zealand
Joined: August 01, 2005
KitMaker: 395 posts
AeroScale: 0 posts
Posted: Saturday, December 31, 2011 - 12:56 PM UTC
,
I think you are admitting defeat too early, just sounds like your pivot angles/distances are a little off. Anywho heres a couple of shots of the original Chopper (rebuilt to original spec for the photo - normally mounted on cutting mat)



PM if you need more measurements.
I've built one myself - heavier duty with pivot point for angle/bevel cuts - and you'll get a lot of satisfaction using something you have made yourself.
thehermit
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Manitoba, Canada
Joined: August 27, 2007
KitMaker: 274 posts
AeroScale: 63 posts
Posted: Saturday, December 31, 2011 - 01:46 PM UTC
LOVELY Roger...just what the doctor ordered ...!! I think my problem is, after lookin at yer great pics, is that I don't have a deep enough groove to bury the blade in and also, I see the arm has a groove machined out to acommodate the razor blade stiffener which causes the blade on mine to sit at an angle...?!

It looks like the blade edge is parallel with the blade arm so that is not the issue. I can't quite tell from the photo but, does the blade start to contact the cutting surface(which also means the part being cut), at an angle so as to perform more of a guillitine type of cut rather than a "chopping" type cut...?

Sorry for getting lomg winded, but you are right, its much more pleasurable to build ones own...IF you can figure the darn thing out...

Regards, Laurie aka " thehermit"
casper
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Nelson, New Zealand
Joined: August 01, 2005
KitMaker: 395 posts
AeroScale: 0 posts
Posted: Saturday, December 31, 2011 - 02:47 PM UTC
Laurie,
you don't want the blade to sit in a groove - this will cause distortion when cutting. The only reason mine is like that is due to wear'n'tear over time (it's about 20 years old) hence the reason it's now mounted on a cutting mat (attached to a alloy base), in the 2nd and 3rd photo you can see the original mounting holes, i've just moved it forward a few times and if I was still using that base I would have moved it again by now.
You want the blade to use a guillotine action otherwise it won't cut cleanly, hope this next photo helps

thehermit
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Manitoba, Canada
Joined: August 27, 2007
KitMaker: 274 posts
AeroScale: 63 posts
Posted: Saturday, December 31, 2011 - 03:00 PM UTC
Aaaaahhhh...I see...! My angle and distance are off so my blade comes down at no angle at all...!!! Thats why it hits the part to be cut parallel causing you to try and "push" the blade throught the part...ain't gonna happen...!

THANKS a truckload mate, you have made the start to 2012 a hoot...!

I will be headin to the work bench on New Year's day and try some mods. I'm sure this trick will get me workin, and I have a small chunk o cutting mat I can use also.

VERY much appreciate all the work you did for me. You are a gentleman and a scholar sir, and I wish you and yours the happiest and most prosperous 2012,
a treat doin biz with ya...G'Day Mate...


Laurie
18Bravo
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Colorado, United States
Joined: January 20, 2005
KitMaker: 6,907 posts
AeroScale: 101 posts
Posted: Saturday, December 31, 2011 - 03:05 PM UTC
Wow, your version is an improvement over mine. Your arm has an are milled out for the thick (upper) portion or the razor blade. People used to complain that theirs didn't make a perpendicular cut. It was because the blade was actually canted. My solution was to add spacer washers betwee nthe blade and the arm. This new milled out area obviates the need to do that.
At any rate, my method may help anyone with the old model...
thehermit
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Manitoba, Canada
Joined: August 27, 2007
KitMaker: 274 posts
AeroScale: 63 posts
Posted: Saturday, December 31, 2011 - 04:03 PM UTC
Hey Robert, I hear ya man, I did the same thing with the washers but I think that aggravates a problem with blade stiffness as the washers cause the blade to "float" a little above the blade arm. With the groove routed out the blade sits flatter against the arm. I got some good pics from Roger and I can see the idea better and will be hittin the bench to work on it some more.

Happy New Year to you and yours.

Laurie
Winterpeg, CANADA