Shopsmith Forums

To say a couple of words about the Prazi Chest Mate dovetail jig - - It works as advertised and is a good jig!

Did I find any problems working with it? Yes!, but only because of my errors of not doing a complete job of labeling the parts. Another issue I thought may occur is - my 1/8" circle saw blade actually cuts a slightly wider kerf than 1/8". I knew this would allow the jig to do a little slopping back and forth when cutting both tails and pins. (What I did to overcome this later) Also even using a sled to saw the kerfs in the indexing boards, I found a kerf at opposite sides of a 12" board could be off by a 64th inch. Prazi recommends sawing kerfs in a 10" board and then sawing that board into 3 pieces and using one of the index bds. for the pins and the other for the tails.

To overcome this, as best I could, I cut a new 14" indexing board and sliced off 4 pieces rather than three. I used the same indexing board (only 3" wide) for both the tails and pins on the same joining corner. This Stopped any variance caused by the slope of the longer kerf in the indexing boards.

Both of these issues (the wide kerfs and the sloping) could cause the dovetails/pins to be off as much as a 1/64" or maybe 1/32". This would be disastrous in a multiple tailed joint.

As it worked out everything fit really well.

Another trick I used was to make the pins a slightly loose fit into the tails. Maybe 1/128th". Just enough so I could detect a slight wiggle after inserting the single test pin between tails.

Concerning cost - The only costs about $120 if you buy it at Sears. Compared with a Leigh jig this is a super bargain. I bought this jig last summer when contemplating making the chest. Tried it out by making a small pine box with 4 pins per side. That fit together with little effort and is still being used. I knew multiple pins would/might offer more challenge - just like a larger number of box joint fingers.

The Prazi chest jig also has attachments to do Box Joints, make mortises and dowels. As with the dovetails, these can be made at random spacing and cover any length.

You will need a 5/8" router bushing and it's best to have a centering cone. (I got by without one, but much fiddling) You will be somewhat limited to the router bits you use for dovetailing. - Either a 7º or 14º bit and a 5/16" straight bit.

This link will take you to a couple videos (the first reference) of using the jig and the complete manual for making dovetails (the second reference).
http://www.google.com/search?source=ig&hl=en&rlz=1G1GGLQ_ENUS294&=&q=prazi+chestmate+dovetail+jig&aq=0sx&aqi=g-sx2g-s1&oq=prazi+Chest+Mate

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Thanks Chuck.

This looks like a tool I could use in my shop. I'll add it to next years list and see how it goes. I still have things on my list from 3 years ago that have not made it to actually getting purchased. If I could come up with a project like yours that makes my project list for the year that would raise its chances.

I see several places now sell them but I guess wishing for a sale might be a long wait. I've had a $140 Kreg jig on my list the last 2 years hoping for a sale and free postage... going to have to bit the bullet this year one way or the other because I have a project coming due.

I guess I should measure the width of my 1/8" blades kerf, how far off are we talking that seem to be a problem for you?

Ed

for an accurate 1/8" kerf you could use one of the outside blades of a stack dado set if you own one.

Betty wrote:for an accurate 1/8" kerf you could use one of the outside blades of a stack dado set if you own one.

Thanks Bob! When I get one of those sets, I'll remember your suggestion. BTW, I thought of getting a new blade, but found even the new Amana blade from Shopsmith, advertises a 0.134" width on the 40 tooth blade and 0.135" on the 50 tooth blade.

This is about the same as my older blade. As we all know, 1/8" = 0.125". Hmmmm!

I agree with Chuck on the Prazi Chest Mate dovetail jig. I have one and have used it a couple of times. I like the look and angle of the dovetails compared to some others. Just remember to shut off your router before removing it from the cut or your's will resemble mine with grooves routed into the knobs.

reible wrote: I guess I should measure the width of my 1/8" blades kerf, how far off are we talking that seem to be a problem for you?Ed

I really don't have an exact measurement of the saw kerf. I noticed a sometimes loose fit, as I built my "trial" pine box. I knew these kerfs would be the same!

Before making the dovetails on the chest I tried to think of all things that could go wrong. My trial pine box came out well, although the same issues were present. Maybe I was just worrying too much! However, when making box joints, I know the spacings are way more critical when making many fingers rather than just a few. I figure the same is probably true of dovetails.

Well - in the final analysis (the chest itself) the kerf width proved to be no issue. The chest went together with no issues. (except I broke out the end of a lower rabbet on the third assembly - clumsy - not really related to the dovetails).

I haven't studied the specs on Freud, or other blades, but as noted above, The Amana is either .134" or .135". That's probably enough to give the wiggle that I was considering to be a possible variant.

Habor Freight clearanced them out about a year ago for $20. Guess I should have picked one up.