January 2008 Edition
LATHES
Rifle Maker Guarantees Accuracy
A Virginia rifle maker stays on target thanks to a lathe
Clay Spencer depends on his Romi M17 combination lathe to help guarantee the accuracy of his rifles
Rifle maker Clay Spencer isn't interested in high production, big chip-producing lathes. He wants repeatable accuracy one barrel at a time.
Spencer builds custom target and sporting rifles, benchrest rifles, 1,000-yard rifles, high-grade hunting rifles, tactical rifles, silhouette pistols, chambers, and muzzle brakes in Scottsville, VA. His firearms are for serious match shooters, hunters, law enforcement, and the military.
Since 1983, none of Spencer's Virginia "Hog" rifles have been returned for poor accuracy. Rifle accuracy is measured in minutes of angle – MOA. It is typically expressed as 1" in 100 yards. He guarantees 1/4 MOA for the Hog rifle, using recommended cartridge loads and bullets. That's five holes within 1/4" area at 100 yards. Spencer can make that guarantee because his machines and machining techniques are that good.
He has sent every other CNC lathe back to the builder, except the M17 combination lathe from Romi USA, Erlanger, KY, currently in his shop.
"The reason it didn't go back is because Romi actually did what it said it was going to do," Spencer said.
The first thing the Romi service engineer did, once the machine was in place, was to align the tailstock and headstock to the bed to Spencer's satisfaction. Then, with special tooling developed over the years, Spencer reamed the spindle bore for perfect concentricity. He then turned a test barrel and took measurements at 10" from the chuck, and right at the chuck, to test run-out.
The M17 passed his test and has made good parts ever since.
Clay Spencer checks the bore of one of his Virginia "Hog" rifles, known for their extreme accuracy
The Barrel is the Greatest Challenge
Of the machining processes that go into making a rifle, it's the barrel that holds the greatest challenge for Spencer.
The barrels are made from 416 stainless steel. After drilling with gun drills, reaming and honing, and button rifling – pulling a carbide form tool through the barrel to form the rifle grooves, Spencer next turns the barrel's outer profile, either straight or tapered, as the customer or rifle stock dictates. He has a series of bushing sets that fit in the M17s reamed spindle, which are machined to match the taper of the barrel.
The barrels are held in a six-jaw chuck with ground jaws that are dial-indicated until chuck and jaw run-out are eliminated. The barrel, threads, and chamber must all fit together within 50-millionths to guarantee the accuracy Spencer is famous for.
"Customers don't believe this little shop can hold 50-millionths on a lathe until they see it for themselves. By the time I'm finished with them, they're sold," he said.
In fact, Spencer boasts he has sold 11 Romi lathes showing customers how he maintains rifle accuracy.
Spencer said he likes the machine's CNC – GE Fanuc 21i-T controls, which are standard on M17s – because they also operate as G-code controls and feature software developed by Romi and GE Fanuc.
"If you can make a part on a manual machine, you can make it simpler and faster on the M17," Spencer said. "You just tell the control what to do and it records every move, so you can do it the same way on the next part." Romi USA
Visit www.rsleads.com/801mn-204
for more information
What do you think?
Will the information in this article increase efficiency or save time, money, or effort? Let us know by e-mail from our website at
www.ModernApplicationsNews.com or e-mail the editor at
pnofel@nelsonpub.com.