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View Full Version : FYI: Radius/Ball cutter castings



dp
01-11-2010, 12:49 AM
Over on PM Craig Donges is offering some Holdridge-like castings for radius/ball cutters. http://www.practicalmachinist.com/vb/showthread.php/radii-cutter-castings-fs-195666.html

They're not something I need and a bit big anyway, but look like a heck of a good deal for what you can get out of it. If you've seen what a real Holdridge goes for you'll appreciate the savings. YIKES!

I appreciate that guys are taking a risk on having these castings made up - I did buy an 18" straight edge casting that is turning out to be a fun scraping project. I wouldn't be surprised to see some of them show up at Forrest's scraping class next month in Seattle.

Edit: Just realized this might violate the no for-sale policy. If so, George, please delete. I'm not involved in any way with the project except that it looks like a good and fun project.

Black_Moons
01-11-2010, 08:31 AM
If anything id want this thread to stay, castings projects are awsome.. Could we have that for sale forum any time soon if this thread must be moved/deleted? Or maybe an OK on 'established community' casting sale projects since they are definately the kind thing we can REALLY benifit from, is made FOR us, and without multiple people willing to buy/show intrest, casting projects are not nearly as viable for single parts.

How exactly do you mount one of those to your toolpost anyway?

japcas
01-11-2010, 08:59 AM
How exactly do you mount one of those to your toolpost anyway?

You make a t slot for the compound that uses two bolts to secure it to the top of the compound. Toolpost gets removed while using it.

I agree about this being a useful project for someone with a lathe big enough to handle this set. I never could find an exact lathe size requirement on the net. All I could fiind is that a holdridge #4 can cut a ball up to 4 inches. So I'd say you would have to be able to swing at least 10 to 12 inches to use one that size.

japcas
01-11-2010, 09:22 AM
I just noticed the scale in the picture under the parts. The biggest casting looks to measure 9 inches tall so I'd say a 10 to 12 inch lathe would handle it.

wierdscience
01-11-2010, 09:28 AM
@ $79.00 a set that quality is a super deal,he should consider making Stuart model knock-offs;) :)

Ian B
01-11-2010, 09:36 AM
Nice, sharp looking castings - but on the inner swivelling piece, shouldn't there be a thicker section in the middle to allow a hole to be bored through for a cutting tool and a couple of screws to hold it in place?

Hard to see the thickness from the pic, maybe there's enough meat.

Ian

blackdog
01-11-2010, 10:15 AM
I just noticed the scale in the picture under the parts. The biggest casting looks to measure 9 inches tall so I'd say a 10 to 12 inch lathe would handle it.

According to Holdridge the No. 4 size fits a lathe with 12" to 15" swing. I've recently had some experience with this trying to fit a 4 on my Clausing 12". It didn't appear to me that it would center without modification so I've determined the No. 3 size is probably more correct for my lathe. BTW, they also make an 8 & a 12 size. Pricey but cool & an attaboy to Mr. Holdridge for being able to defend his patent all these years.

David Brown
So Cal

dp
01-11-2010, 11:05 AM
Nice, sharp looking castings - but on the inner swivelling piece, shouldn't there be a thicker section in the middle to allow a hole to be bored through for a cutting tool and a couple of screws to hold it in place?

Hard to see the thickness from the pic, maybe there's enough meat.

Ian

Eyeballing the ruler in the image it looks like the smaller harp is about 3/4" to 7/8", and the sides are parallel.

Edit: Here's a #4 Holdridge on Ebay. Makes me want to say YIKES again!
http://cgi.ebay.com/HOLDRIDGE-MODEL-8D-RADII-CUTTER-SET_W0QQitemZ140371671337QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item20aecdb929