The Sherline Miniature Machinist's Newsletter
Number 72, July 22, 2014
New Product Spotlight
ï Scrolling Chucks Improved
The new 3-jaw chuck on the right is slightly taller due to the additional material that now spans the bottom of the jaw slot, providing more strength and consistent slot width.
Keeping a perfectly consistent slot width during the manufacturing process has always been hard to do. As succeeding slots are machined, the upper half of the chuck body becomes more flexible, making it more difficult to maintain a perfectly consistent width. This means each chuck jaw has to be custom ground to fit the slot. By changing the height of the upper chuck body to allow a web of material to remain under the slot, Sherlineís shop foreman Karl Rohlin has made the machining process much more consistent. The lower body (scroll) is increased in height a corresponding amount to compensate. The new chucks turn much more smoothly and evenly as a result.
The new chuck design and added material will add $10.00 to the price of each scrolling chuck, but the result is a sturdier, more consistent product. We are just about out of the old chucks and the new design is being phased in as old stock runs out. 3.1" 3-jaw chucks are now in stock. Next up will be the 3.1" 4-jaw self-centering chucks. Later on down the line the 2.5" chucks will eventually be changed as well.
Sherline offers backlash adjustment on most axes, but older lathe crosslides did not feature backlash adjustment. Chris Reuby has come up with a way to remedy that. The following is his solution that can be applied to the lathe or mill.
a longtime Sherline owner (currently have a 4400 lathe and also a mill), one
I always had trouble with was keeping the backlash adjustment on the cross-slides in proper
adjustment. Sherline has done a good job with the adjustment star wheels on the threads, but where I had problems has always been where the ends attach to the hand wheels. The small set screw on the hand wheel is all that keeps the threaded shaft held tight at the outer plate - and it always seems to drift with usage, opening up a small gap with the plate, and letting the cross slide chatter, especially in milling operations (the long axis on the mill table is the one I've had the most trouble with). I noticed the way that the CNC fittings were designed with a set of bearings and a preload nut - looks like that should work great, but hard to replicate on my own for the hand wheel setup.
Recently had an idea to correct this flaw - I had obtained a spare end plate (did not want to risk messing up the one in use if the idea did not work!), and added on a second plate inside it to capture the fitting on the end of the shaft. Easier to show than describe, below are some pictures of it. I made the new plate out of brass to test the idea (it worked like a charm - holding really tight tolerance, easy to adjust). I may remake it out of steel. I am planning on making three more to do the other shafts on the lathe and mill.
Here it is assembled with the shaft - the cutout in the new brass piece is to allow it to sit under the cross slide.
Front view: As you can see, to adjust the new plate all I need do is remove the
handwheel and tighten/loosen the two new socket head screws. I put on some
removable LoctiteÆ to hold them in place.
Side view: showing the gap between the platesóthe counterbore in the new plate
is less than the thickness of the flange on the fitting, allowing for takeup if there is
wear over time.
Showing the pieces: the threaded rod and its fitting were not changed at all, just
the two new holes for the set screws in the existing plate.
Here is a measured drawing of what I made.
Did you know?
Model Engineering Shows
Sherline attended the 2014 North American Model Engineering Society Expo in Wyandotte (Detroit), Michigan April 26th and 27th. Both attendance and sales were up substantially this year. We would like to thank the NAMES staff for putting on such a professional show and also all our customers who stopped by the both to purchase or just say hi to Jerry Kieffer, Jim Clark and Craig Libuse. We will be back again next year and hope to see you there.
∑ Black Hills Model Engineering Show, Next show--September 20-21, 2014, Rapid City, SD. The show is held the 3rd weekend of September each year. See www.blackhillsmodelengineeringshow.net or contact Clif Roemmich at email@example.com
∑ Home Industrial Craftsman Show (Formerly GEARS --Gas Engine Antique Reproduction Show), Portland, OR area, late September. See http://gears.cbnetsolutions.net/. New management for 2013, new location (Oregon Rail Heritage Center) and new web site address. The 2013 show will be September 27-28, 2014.
∑ Estevan Model Engineering Show, Estevan, Saskatchewan, Canada, October (Next show: October 18-19, 2014 the weekend following Canadian Thanksgiving). For updates and info see http://estevanmodelengineeringshow.com/
∑ 15th Annual Model Engineering Show, Saturday October 25, 2014, American Precision Museum & Windsor Recreation Center, 29 Union Street, Windsor, VT. Model Exhibits and Miniatures, Special Demonstrations all Day. Vendor and exhibitor pre-registration is recommended. Call the museum (902.674.5781) or register online. E-mail: firstname.lastname@example.org. Web site: www.americanprecision.org
†(Send us your show information and we will post it here.)
Joe Martin Craftsmanship Foundation News
New ExhibitsóSeven CO2 engines by Stephan Gasparin, Hoosier and Brown Junior were contributed for display by Edward Swenton, Jr. Also included is a technically amazing, super light-weight, rubber powered, free-flight aircraft model by Russian champion Andre Badoux. Dennis Hodgkins donated a 4-1/2" diameter model of a shipís propeller made from aluminum salvaged from downed Japanese aircraft at the battle of Midway. Joe Bridi donated three aircraft models including a Douglas DC-3 and Sikorsky VS-44A flying boat with Catalina Airlines colors carved from wood by Ralph Sarosa and a diecast metal B-24 Liberator bomber. Model engineer Jack Randall brought in two very beautifully built engines for display. One is a Fairbanks Morse hit-n-miss engine with a screen cascade radiator, and the other is a 2-cyl reversible marine steam engine. All the above exhibits can be seen on the DISPLAYS page on the museum web site.
Club VisitsóThe Palomar Model A Ford Club stopped by with a nice group of original and restored Model Aís on Saturday, July 12th. On Monday, July 14th the museum hosted a larger group of Model T Fords that were part of a national event hosted by the San Diego Region of the American Model T Ford Club. Photos of the events can be seen on the Group Visits page.
Attendance RecordóOn Monday, July 14th we had 122 visitors sign in which is a record for a weekday. (The Saturday record is 177 visitors.) Several years ago Joe Martin set the then seemingly unattainable goal of entertaining 30 people per day. We now rarely fail to exceed that goal and often double or triple it.
Road ConstructionóAs of Tuesday, July 15th the intersection at Melrose Drive and Lionshead Avenue was reopened to traffic. We apologize for the inconvenience some of our customers faced getting to the museum during the past year and are glad things are finally back to normal.
Video SurveillanceóIn order to provide an enhanced level of security for our exhibits, the museum recently installed motion activated high definition video cameras inside and out.
New StaffóAs of July 1st, Bob Rabourne came on board as Museum Manager on Mondays and Tuesdays. He will also continue in his additional position as Community Outreach Director, letting local organizations know about what we have to offer the local community.