Williams scope mount fixture jig

[mookiie]

Has anyone used the Williams scope mount fixture jig as seen below for a drill and tap job?

http://www.brownells.com/.aspx/pid=16326/Product/SCOPE-MOUNT-DRILL-FIXTURE


Thanks

 

[rcmodel]

No.

Aren't you the guy doing the SKS one-time job?

If so, glue & clamp the mount on with epoxy while bore-sighting it to get it aligned.
Then use the screw holes in it for the jig to center-punch, align, & drill the holes in the receiver.

rc

 

[mookiie]

Rc - yes I am working on drilling and taping an sks. I was planning to do exactly what you recommended above. I have had lot of people telling me that you cannot do a proper tap job on a drill press and I have never done a tap job so I plan to practice on some metal stock first. I just wanted to see if this jig is any good since some have said a jig s nesacary to get the wholes lined up. Thanks for the info!

 

[rcmodel]

Well, it's apparent by now you are going to do this, despite good advice to farm it out for a one-time job.
So, I'll try to help you.

The way you break taps is:
1. Using low quality, cheap, or dull taps.
2. Getting them off-center with the hole and putting side force torque on them.
3. Letting chips build up between the flutes and bind up or gall in the hole.
4. Using no or poor quality thread cutting oil.

SO, some sort of guide or jig to keep the tap perfectly straight with the drilled hole is critical unless you have the skilled hands of an old machinist.
You don't yet, and tapping a few practice holes in mild steel won't give you some.

As for a jig and using the mount to align the holes?
A tap guide can be a complex as the $150 Williams jig.
Or as simple & cheap as a 1"x2" block of brass or steel bar stock with a clearance hole for the tap you can clamp to the mount to keep the tap straight with the hole while you crank on it.

Do-Drill is very good cutting oil. Get-sum.
http://www.brownells.com/.aspx/pid=1120/Product/UNIVERSAL-DO-DRILL

rc

 

[Fleet]

I've have one, it's great for some things, not so great for others. It's the cats pajamas for putting new shotgun beads on quickly after shortening the barrel if it's got a rib. Also works well for actions with a round or flat top and flat sides.

 

[mookiie]

Thanks Fleet. It sounds like it may be worth the money for any future jobs I come up with. Thanks!

 

[UlicniTrkac]

it is an old thread, but I didnt want to start a new one - I got this SunOptic Jig, but I have problem with it - these bushings wont go in the hole that they are meant to - did you encounter similar problem?
Thanks in advance

 

[Zeke/PA]

Rc - yes I am working on drilling and taping an sks. I was planning to do exactly what you recommended above. I have had lot of people telling me that you cannot do a proper tap job on a drill press and I have never done a tap job so I plan to practice on some metal stock first. I just wanted to see if this jig is any good since some have said a jig s nesacary to get the wholes lined up. Thanks for the info!

"can't do a proper tap job on a drill press"?
I did quite a few "tap jobs" using my drill press!
A developed "feel" is important when tapping to ensure that the tap is cutting freely guarding against tap breakage.
A 6x48 tap should be handled with some caution and expertise!

 

[BBBBill]

Old but not dead apparently. I'm not familiar with the SunOptic. It looks very much like the old B Square jig, which I have (as well as the Williams and Forster jigs). Mine works well with no such issues. Normally the bushings go all the way through the hole in the jig.... unless SunOptic designed it that way.... Can't imagine why they would.
Your options - Either return it to the manufacturer or fix the problem. If the bushing is a snug slip fit otherwise, you could probably just scrape the burr that is preventing the bushing from going all the way in. If you do so, make sure you only work the spot that is causing the problem. The accuracy of the jig depends (partially) on the fit of the bushing to the hole.

 

[UlicniTrkac]

It is the same as B Square from what I see. Unfortunately, return isnt an option for me (shipping would cost more than jig itself, I am not from US), so I will have to address this problem as advised. But from what I can see, there is no burr preventing the bushing go in.

 

[rcmodel]

Finish build-up then.

Chuck the bushing in your drill press, spin it up, and polish it down until it will fit with a strip of emery cloth.

rc

 

[morcey2]

What he said. ^^^

I've go the same jig and a couple of scrap Mauser actions on which to practice. The bushings are very tight in the holes in the jig, but they will go in. There appears to be a very small amount of galling in the holes of mine, but it works.

Matt

 

[Blue68f100]

Have you measured the parts to see what the interface is? If only a few 0.001" a thermal fit may work.

Put the bushings in the freezer and heat up the base.

 

[rcmodel]

They are supposed to be an easy slip fit so you can pull the bushing out with your fingers to clean the metal chips out of the holes, drills, and taps.

A Thermal tight fit requiring a freezer and a torch to get them in & out of the jig would be totally counter-productive to using them correctly to drill & tap holes.

rc

 

[UlicniTrkac]

emery cloth did the trick.

thanks fellas

just to add, SunOptics has a great support service - they responded promptly, and offered to replace the existing bushing with a new one.